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Activités s'adressant aux étudiants

Étudiants des cycles Supérieurs
L’ACDP/CAPD reconnaît que la voix de l’avenir de la dentisterie pédiatrique au Canada se trouve parmi sa population d’étudiants diplômés. Que les étudiants suivent leur programme au Canada ou aux États-Unis, il y a un lien commun qui les unit – ils sont reliés entre eux et à leurs collègues membres actifs de l’ACDP/CAPD par le biais du site Web de l’ACDP/CAPD.Les étudiants sont invités à transmettre les annonces et(ou) les nouvelles qu’ils souhaitent afficher sur le site Web à propos d’activités liées aux affaires étudiantes, aux réunions ou aux recherches scientifiques en s’adressant au webmestre.

Étudiants de premier cycle

L’ACPD/CAPD reconnaît également l’importance des étudiants de premier cycle en médecine dentaire qui s’intéressent activement à la dentisterie pédiatrique. Par le biais du Prix du Dr Norm Levine décerné aux étudiants de premier cycle, l’ACPD/CAPD continue d’encourager et d’appuyer le perfectionnement de ces jeunes en formation. Ce prix est offert à toutes les écoles de médecine dentaire du Canada.



Dépôt d'abrégés

Il y a des directives précises que les étudiants diplômés doivent respecter s’ils veulent déposer des abrégés en vue des Présentations de travaux de recherche 3M ESPE et(ou) y assister. Voici les fichiers PDF qui comportent l’information nécessaire pour la participation des étudiants :

     

 

 

Directives 2017 pour le dépôt des abrégés scientifiques 

 

Veuillez noter que la date limite de dépôt des abrégés est fixée au 10 juillet, 2017.

 


Présentations de travaux de recherche


L’édition annuelle des Présentations de travaux de recherche d’étudiants diplômés 3M ESPE est le fruit du partenariat entre 3M ESPE et l’ACDP/CAPD. L’argent que donne généreusement 3M ESPE est remis aux étudiants diplômés canadiens en dentisterie pédiatrique qui présentent leur sujet de recherche lors de l’assemblée annuelle de l’ACDP/CAPD.

 

Chaque année, dix étudiants diplômés sont invités à l’assemblée annuelle afin de présenter leur travail de recherche. Les étudiants invités sont admissibles au prix 3M ESPE décerné à l’étudiant ou à l’étudiante qu’un jury aura choisi(e) à titre de meilleur(e) présentateur ou présentatrice. 3M ESPE remettra en outre un échantillon de sa gamme de produits à tous les présentateurs. 

 

En plus d’être admissibles au prix 3M ESPE, les présentateurs se verront offrir ceci par l’ACDP :

  • le transport aérien aller-retour vers la ville hôte de l’assemblée annuelle;
  • deux nuits d’hébergement à l’hôtel où se tient le congrès; et·       
  • l’inscription gratuite à toutes les séances du congrès, y compris les activités sociales.


                                   Le Dr Edwin Chan reçoit un chèque de 1 000 $ des mains de Gigie McGlynn, de l’entreprise 3M,                                                                        lors de l’assemblée annuelle 2016 de l’ACDP/CAPD.



Bourse du Dr. Keith Titley

Bourse d’études supérieures en dentisterie pédiatrique du Dr Keith Titley




 


 

Le Dr Keith Titley a été professeur titulaire au département de dentisterie pédiatrique de l’Université de Toronto de 1970 à 2008. Keith a travaillé sans relâche à enseigner la dentisterie pédiatrique tant au premier qu’au cycle supérieur.


Il a été un mentor et un ami pour de nombreux étudiants diplômés se spécialisant en dentisterie pédiatrique, et les fruits de son travail rejaillissent aux quatre coins du Canada sous forme de soins buccodentaires avancés prodigués aux enfants, de formation et de recherche en dentisterie pédiatrique. Il a été directeur d’innombrables thèses de diplôme en dentisterie pédiatrique et d’aussi nombreuses thèses de maîtrise en dentisterie pédiatrique.


Keith a aussi travaillé d’arrache-pied tout d’abord comme examinateur en chef, puis comme registraire du Collège royal des chirurgiens dentistes du Canada. Ce faisant, il a mis en relief l’importance d’une formation avancée dans le cadre des programmes de spécialisation reconnus au Canada et a ainsi veillé à ce que la démarche d’examen soit juste et équitable pour toutes les spécialités dentaires.


Keith a aussi été un grand adepte de la cause de l’Académie canadienne de dentisterie pédiatrique, dont il est membre.

Reconnaissant le travail à la fois discret et inlassable du Dr Titley dans le domaine de la dentisterie pédiatrique, cette bourse de l’Académie canadienne de dentisterie pédiatrique a été nommée en son honneur.



ADMISSIBILITÉ ET DÉMARCHE DE DEMANDE :



Lire le détail des paramètres et directives de demande pour cette bourse (en anglais seulement). 


Le 31 octobre 2016 st la date limite pour recevoir les applications.



Télécharger le formulaire de demande de la bourse d’études supérieures en dentisterie pédiatrique du Dr Keith Titley (en anglais seulement).

(Après avoir rempli le formulaire en format Microsoft Word, suivre les directives figurant dans le document intitulé paramètres et directives ci-dessus.)


Télécharger le formulaire de déclaration du conseiller de la bourse d’études supérieures en dentisterie pédiatrique du Dr Keith Titley (en anglais seulement).

(Une fois le formulaire de déclaration de votre conseiller dûment rempli en format Microsoft Word, suivre les directives figurant dans le document intitulé paramètres et directives ci-dessus.)

 


Prix du Dr. Norman Levine décerné aux étudiants de premier cycle



LAURÉATE DU PRIX 2017



La Dre Julia Rukavina remet le prix du Dr Norman Levine à la Dre Bridget Yeung. 

Elles se tiennent debout devant le portrait du Dr Levine.

La Dre Rukavina fait remarquer que les portraits exposés à la Clinique pédiatrique de l’U. de T. ont été peints par Mlle Amanda Arlotta, étudiante à l’Université de l'École d'art et de design de l'Ontario (OCADU) et fille de notre secrétaire au département de dentisterie pédiatrique.





LAURÉATES DU PRIX 2017


FÉLICITATIONS À LAURA ROSE MACDONALD, DE L’UNIVERSITÉ DALHOUSIE,  

ET À GUILLAUME GOULET, DE L’UNIVERSITÉ LAVAL.

 


   
On aperçoit ici Laura Rose MacDonald, de l’Université Dalhousie, en compagnie du Dr Ross Anderson (à l’occasion de la remise du prix du Dr D.E. Williams). Guillaume Goulet est photographié aux côtés de sa professeure, la Dre Suzanne Hébert, et de la doyenne, la Dre Cathia Bergeron.                    © Université Laval / Pascal Duchesne

Comme le stipulent nos Statuts et Règlements (article 4.2.5)…


Les étudiants de premier cycle présentant une preuve d’inscription active à un programme d’études en dentisterie agréé par la Commission de l’agrément dentaire du Canada ou un organisme d’agrément avec lequel la Commission de l’agrément dentaire du Canada a conclu une entente réciproque d’agrément peuvent faire une demande d’adhésion à titre de membres étudiants de premier cycle.

Tous les membres étudiants sont dispensés du versement des cotisations de membre et reçoivent sans frais des copies de toutes les communications et publications d’intérêt général destinées aux membres.


En outre… Les membres étudiants de premier cycle peuvent assister aux assemblées de l’Académie une fois inscrits et après avoir payé tous les frais afférents. Tous les détails se trouvent à l’article 4.2.5 des Statuts et Règlements.




Le Dr Norm Levine fut, en 1960, le premier stagiaire de cycle supérieur dans un programme de dentisterie pédiatrique à la faculté de chirurgie dentaire de l’Université de Toronto. De 1976 à 1993, Norm fut professeur et chef du département de dentisterie pédiatrique à la faculté de chirurgie dentaire de l’Université de Toronto.

 

Ce fut un chef de file respecté et reconnu mondialement dans le domaine des soins dentaires aux personnes handicapées.

 

Vouant une passion inébranlable à la dentisterie pédiatrique, Norm a su rehausser le profil et la réputation de sa spécialité.

 

The Bear (l’Ours), comme on le surnommait, était un géant doux, humain et généreux. On lui a remis l’Ordre du Canada pour souligner son engagement à l’égard de la dentisterie pédiatrique et des soins buccodentaires destinés aux personnes ayant des besoins spéciaux. Il a insufflé cette passion à de nombreux stagiaires de premier cycle et de cycles supérieurs en dentisterie pédiatrique, dont plusieurs sont issus du programme dans lequel il a enseigné et dont il devint directeur. Ses anciens étudiants pratiquent maintenant aux quatre coins du Canada et du monde – dans des cabinets privés, des services hospitaliers et le monde universitaire – en faisant la promotion de cette même quête d’excellence en dentisterie pédiatrique.

 

C’est avec grand honneur et respect que les membres de l’Académie canadienne de dentisterie pédiatrique ont créé le Prix du Dr Norman Levine décerné par l’Académie canadienne de dentisterie pédiatrique aux étudiants de premier cycle en dentisterie. On remettra à chaque faculté canadienne de dentisterie accréditée un prix par année afin de récompenser un étudiant ou une étudiante de troisième ou quatrième année en DDS/DMD, qui démontre une aptitude particulière et une passion pour le domaine de la dentisterie pédiatrique et(ou) les soins buccodentaires destinés aux personnes ayant des besoins spéciaux.

 

Le lauréat ou la lauréate sera nommée par le directeur du programme de premier cycle en dentisterie pédiatrique en consultation avec le comité d’attribution des prix de sa faculté. Le lauréat ou la lauréate recevra 200 $.

 

Les facultés canadiennes de dentisterie accréditées peuvent transmettre, une fois par année, les noms des étudiants mis en nomination, en précisant pour quelle année leur candidature est soumise, ainsi que leur facture, à l’Académie canadienne de dentisterie pédiatrique à info@capd-acdp.org.

 

.  

2016 Abstracts and Archives



2016 Abstracts, Annual Meeting in Toronto, Canada



2016 Abstracts, Toronto, Ontario  

  • Edwin Chan, Regenerative endodontic treatment of immature necrotic permanent teeth: 30-month follow-up.
  • Kunal Chander, Effects of Aging on Dentin Bonding and Mechanical Properties of Restorative Glass Ionomer Cements.
  • Anne-Sophie Fortin Pagé, Breastfeeding improvement in young infants diagnosed with ankyloglossia after a lingual frenotomy.
  • Shuang Liu, Canadian pediatric residents’ perceptions, training and knowledge of infant oral health.
  • Simrit Nijjar, Comparison of Manitoban general and pediatric dentists behaviour guidance technique usage and preference.
  • Becky Olacke, The Effect of Biophysical Characteristics and Dosing on Pediatric Oral Sedation Outcome.

Regenerative endodontic treatment of immature necrotic permanent teeth: 30-month follow-up


Dr. Edwin Chan, University of Toronto, Toronto, Ontario


Introduction: The treatment of immature necrotic permanent teeth presents several clinical challenges in endodontics. Regenerative endodontic procedures (REPs) permit root development, increase in canal wall thickness and apical closure. 


Objective: The purpose of this study was to evaluate the long-term clinical and radiographical outcomes of REPs over a 30-month period. 


Methods: This longitudinal cohort study was carried out at the Division of Dentistry of the Montreal Children’s Hospital. Twenty-eight immature necrotic permanent teeth from 22 patients were included in this study. All teeth were treated with a standardized REP protocol. Patients had follow-up appointments at 1, 2, 3, 6, 12, 18, 24 and 30 months. At each appointment, clinical examination was performed to monitor signs and symptoms. Radiographic evaluation was also performed by a calibrated endodontist in order to analyze different parameters. 


Results: Our results demonstrate a high survival rate (96.4%), clinical success (92.8%) and resolution of apical pathology (100%). Significant increases in the average root length (8.1%; p<0.0001) and radiographic root area (11.6%; p=0.03) were observed after an average of 30 months follow-up. In the study period, a considerable decrease in apical diameter was also noted (p<0.0001), with 30.8% of the cases showing a complete apical closure. Teeth with more immature stages of root development had a higher percentage of change in root thickness, length and apical diameter; however, these results were not statistically significant. 


Conclusion: REPs showed high resolution of apical pathology and clinical success without significant complications in treating immature necrotic permanent teeth over a 30-month period. An increased root thickness, root length and apical closure was observed, although a clinically significant change was not achieved in all cases.



Effects of Aging on Dentin Bonding and Mechanical Properties of Restorative Glass Ionomer Cements.


Dr. Kunal Chander, University of British Columbia, Vancouver, British Columbia


Objectives: To examine the effects of artificial aging on shear bond strength to dentin (SBS), flexural strength (FS) and diametral tensile strength (DTS) of four restorative glass ionomer cements.


Methods: Sound extracted human permanent molars were ground to flat occlusal dentin surface and fixed in a circular mold with an auto-cured acrylic resin for the shear bond strength test. The teeth were randomly divided into four groups: (1) Fuji II LC (FLC), (2) Equia (EQ), (3) Ketac Nano (KN), and (4) Ketac Molar (KM). For each dentin surface, two glass-ionomer cylinders were bonded. Specimens were stored in artificial saliva (37°C) and tested at 24-hour and 6-month period. Flexural strength bars (25mm x 2mm x 2mm) and diametral tensile strength discs (4mm x 2mm) for each material were fabricated, stored in artificial saliva (37°C), and tested after 24-hour and 6-month period. An additional flexural strength study was conducted with glass ionomer specimens stored either in distilled water or artificial saliva (37°C), and tested at 24-hour and 2-month periods. Data were analyzed in a two-way ANOVA (p<0.05) with post-hoc Tukey’s tests to compare interactions.


Results: Dentin-glass ionomer bond strengths (SBS) were stable after 6-month storage, however a significant decrease was observed for KN (Table 1). There were no significant differences in SBS among the four glass ionomers. The DTS did not change significantly after aging except for FLC group (Table 1). The FS increased significantly after aging in all groups (Tables 1 & 2) regardless of the storage media (water or saliva). Storage media did not affect flexural strength of materials (Table 2). FLC group presented significantly higher diametral and flexural strength compared to other groups (Tables 1 & 2).


Conclusions: Restorative glass ionomer cements presented stable dentin bonds, except for KN. Flexural strength improved over time for all glass ionomers, regardless of the storage media. DTS did not change over time, except for FLC. Overall, FLC demonstrated superior mechanical properties compared to the other materials studied.


Acknowledgements: UBC Faculty of Dentistry (Start Up Funds and Graduate Program Research Funds), GC America and 3M/ESPE.



Breastfeeding improvement in young infants diagnosed with ankyloglossia after a lingual frenotomy.



Dr. Anne-Sophie Fortin Pagé,  CHU Sainte-Justine, Department of Pediatric Dentistry, Montreal, Quebec


Objectives: To assess the outcomes of lingual frenotomy on breastfeeding efficacy and mother's pain among infants diagnosed with ankyloglossia. The secondary objective is to assess whether the timing of the frenotomy has an impact on the outcome.


Methods:. Infants referred to the Montreal Children’s Hospital by a health professional or a certified lactation consultant for a frenotomy were evaluated for enrollment in this cohort study. Healthy infants under 3 months of age, who had difficulty breastfeeding, a poor score on the Hazelbacker Assessment Tool for Lingual Frenulum Function (HATLFF) and whose parents accepted the frenotomy were included. Ankyloglossia was classified into four types according to Coryllos classification. Mothers’ complaints, weight gain since birth and feeding methods were noted. Infant Breastfeeding Assessment Tool (IBAT) and Numerical Pain Rating Scale (NRS) were completed by the mothers at baseline evaluation, 7 days and 31 days after the frenotomy. A 6-month telephone follow-up was done to assess continuation of breastfeeding.

Descriptive statistics and Related-Samples Wilcoxon Signed Rank Test were performed to evaluate differences in IBAT scores and NRS scores before and after frenotomy. Additionally, Independent-Samples Mann-Whitney U Test was used to compare the timing of frenotomy (<14 days old vs. ≥ 15 days old).


Results: Sixty-nine infants diagnosed with ankyloglossia were included in the study. Frenotomy were more performed on males (61%) than females (39%) and the average age was 17 days. The majority of infants presented with ankyloglossia type 2 (41%), followed by type 3 (38%), type 1 (17%) and type 4 (4%). In all types, IBAT and NRS scores improved significantly between the baseline and 7 days (p<.001) and between 7 days and 1 month (p<.001). Fifty-five percent of infants were 14 days or less and forty-five percent were 15 days and more at the time of the procedure. Infant age at the time of frenotomy was not significantly correlated to breastfeeding scores or pain rating.


Conclusions: Frenotomy procedure may significantly improve IBAT and mothers's NRS in infants presenting with ankyloglossia and breastfeeding difficulties, regardless of the timing of the procedure. Ankyloglossia should always be examined in infants presenting with breastfeeding difficulties, and if detected, frenotomy may be considered by healthcare providers.




Canadian pediatric residents’ perceptions, training and knowledge of infant oral health.


Dr. Shuang Liu, Interfaith Medical Center, Brooklyn, New York


Objectives:  The purpose of this survey was to assess the current perceptions of Canadian medical

pediatric residents regarding their education in infant oral health.


Methods: Data was collected in collaboration with the Canadian Pediatric Program Directors’ (CPPD)

research group. The CPPD relayed the survey electronically to all 625 Canadian medical pediatric

residents in June of 2015.The questionnaire was an anonymous self-administered 17 question survey asking

respondents the number of hours they received in oral health training, perceptions on their training,

and comfort levels in assessing infant oral health. Five knowledge questions were included.

Responses were analyzed using descriptive statistics in addition to statistical testing.

Analysis was performed to determine whether demographic variables had an effect on whether

knowledge questions were answered correctly.


Results: 187 surveys were completed out of a total 625, achieving a response rate of 29.9%. 70.6%

residents indicated receiving less than 1 hour of training on the oral health exam, 22.5% received

between 1 to 2 hours of training, 5.3% received 2 to 4 hours of training and 1.1% residents received

more than 4 hours of training.

In response to the question of respondent’s perception of adequate training on the infant oral

health examination, 4.8% agreed that they received adequate training. No respondents strongly

agreed with the statement, 11.2% strongly disagreed with the statement, 57.2% disagreed and

26.7% were neutral.

Residents comfort levels in performing an infant oral health exam were as follows: 10.1%

very uncomfortable; 57.8% uncomfortable, 4.3% neutral; 5.9% comfortable; and 0.5% very

comfortable.

In response to the question of residents’ perception that oral health is an important

component of overall health, 66.8% strongly agreed, 31.6% agreed, 1.1% were neutral, and 0.5%

disagreed.

Responses to whether the pediatrician plays an important role in ensuring adequate oral

health were: 22.5% strongly agreed, 64.2% agreed, 11.8% neutral and 1.6% disagreed.

Of those surveyed, 6.4% respondents correctly answered all five knowledge questions. The results

to the knowledge questions are listed in Table 2. To allow for a better summary and analysis of data,

demographic variables were placed into 2 groups and the mean of the coded scores in response to

the 5 questions were compared.


Conclusion: There is a disconnect between the training currently received by pediatric residents and the

knowledge base required to adequately aid in insurance of satisfactory oral health amongst the

Canadian pediatric population.



Comparison of Manitoban general and pediatric dentists behaviour guidance technique usage and preference.



Dr. Simrit Nijjar, University of Manitoba, Winnipeg, Manitoba


Objective: To examine differences in the usages and otherwise preferences of behaviour guidance techniques between Manitoban general and pediatric dentists when considering year of graduation, training locations, and source of training.


Methods: Surveys using SurveyMonkey were emailed via the Manitoba Dental Association to a random 25% sample of general dentists and all pediatric dentists (145 general dentists, 19 pediatric dentists) in Manitoba. Questions regarding type of dentist, year of graduation, place of undergraduate/graduate training, ranking of pharmacological and non-pharmacological behaviour guidance techniques, and sources of training of the techniques were created. Statistical analysis was performed using the statistical software in SAS 9.3 (SAS Institute Inc., Cary, NC, USA). The nonparametric test Wilcoxon Mann-Whitney test was performed on all data by considering all behaviour guidance techniques as continuous variables. Significance levels were considered at alpha <0.05 and at 95% confidence interval (CI).


Results: A total of 87 completed responses were collected (72 general dentists, 15 pediatric dentists). Statistically significant differences were found in voice control and oral sedation overall. In those that graduated before 1998, tell-show-do and oral sedation had statistically significant differences. For those that graduated after 1998, oral sedation and general anesthesia had statistically significant differences. The usage of voice control and the otherwise preference of oral sedation for those trained within Manitoba were found to be statistically significant between the general dentists and pediatric dentists. These findings although statistically significant were judged not to be of clinical significance as the rankings were usually within one number. For the source of training, pediatric dentists mainly chose undergraduate and graduate training as their main source for most behaviour guidance techniques while general dentists mainly chose undergraduate only as theirs. For both the general and pediatric dentists, the most favoured non-pharmacological technique was tell-show-do and the least favoured was protective stabilization. In the pharmacological groups, nitrous oxide sedation was most favoured and IV sedation was least favoured.


Conclusions: In general, there were few statistically significant differences in the usage and otherwise preference of behaviour guidance techniques between both general and pediatric dentists when considering the year, source, and location of training; however, there were some clinically significant findings. Overall, tell-show-do and nitrous oxide sedation were found to be the most favoured in their respective categories while protective stabilization and IV sedation were the least favoured in their respective categories for both general and pediatric dentists of Manitoba.



The Effect of Biophysical Characteristics and Dosing on Pediatric Oral Sedation Outcome.


Dr. Becky Olacke, University of Washington Center for Pediatric Dentistry, Seattle, Washington


Objectives: Overweight and obese patients require special consideration because of physiologic differences. For such patients dosing sedation medications at actual weight may result in a relative overdose. Currently, there is no recognized dosing scalar for pediatric procedural sedation. This study examined the biophysical characteristics of pediatric dental sedation patients to determine the effect of child weight and the impact of medication dose on sedation success.


Methods: Records of pediatric dental sedations performed at a university-based dental clinic from Feb 2 2011 through Feb 1 2016 were reviewed. Healthy children aged 24 -144 months, who received an oral preparation of meperidine (1.5mg/kg), midazolam (0.3mg/kg), and hydroxyzine (1.0mg/kg) and whose treatment was supervised by the same attending pediatric dentist were included. Sedation dose was calculated using a simplified IBW dosing scalar, the lesser of actual weight or the Centers for Disease Control and Prevention (CDC) 50th weight for age percentile. Patient demographics and biophysical characteristics were recorded and used to calculate body mass index (BMI) percentiles. The sedation dose was compared with the child’s actual weight to determine if the dose delivered was therapeutic or sub-therapeutic. Sedation success was analyzed to determine association with dose received.


Results: The sample population consisted of 427 children (mean age = 76.8 months, SD = 21.6 months). The overall success rate, measured by the Houpt scale, was 74% (N=315). There was not a significant difference in success rate by gender, ASA status, insurance status, CDC BMI percentile for age, CDC weight for age percentile, or dose delivered. Older age category and simple treatment type were significantly associated with sedation success (P = 0.036 and P = 0.045 respectively). Chi-squared tests were used to evaluate the association between categorical variables and sedation outcome. The calculated ideal and lean body weights of the study participants were significantly greater than the dosing weight used (P < 0.001 and P < 0.001 respectively) and several patients in the upper quartile received sedation during the study period.


Conclusions: Patients in this study were on average heavier than the CDC 50th weight for age percentile. The results suggest that to avoid inadvertent sedation of overweight and obese patients BMI percentile should be considered in sedation case selection and dosing.




 

Abstracts from 2015, 2014, 2013, 2011 and 2009 may be found here



2015 Abstracts, Halifax, Nova Scotia


Investigation of Accessory Canals in Primary Molars, A Micro-Computed Tomography Study


Dr. Mark Berscheid, University of Manitoba


Objectives: This study was designed to examine accessory canals in the furcation area of extracted primary molar teeth using micro-computed tomography.

Material and Methods: Extracted primary maxillary and mandibular molars (n=65) were scanned at a resolution of 9.0 µm in a micro-CT scanner (Skyscan 1176). The patient age, as well as type of tooth (maxillary versus mandibular, first versus second molar) were recorded for each tooth and DataViewer v. 1.5.1 was used to interpret scanned images. Presence or absence of canals, canal patency, number of canals, and size of canals was recorded for each tooth. Collected data was analyzed using SPSS 20.0 for Windows. Fisher’s Exact and Kruskal-Wallis tests were used to identify association between variables.


Results: Canals were observed in the furcation area of 83% of molars scanned, and patent canals were found in the furcation area of 8% of molars. The mean number of canals per tooth was found to be 2.6. Second molars were observed to have a significantly higher number of canals than first molars (p<0.05). No significant association was found between patient age and the number of canals present. Also, no significant relation was found between tooth type or patient age and diameter of canals.


Conclusions: The following conclusions can be made based on the results of this study:

1.   While the majority of primary molar teeth have accessory canals in the furcation area, only a minority of primary molar teeth have accessory canals that are patent.

2.   Micro-computed tomography is an effective tool for analyzing accessory canals in the furcation region of extracted primary molars.

3.   Other factors besides accessory canals may be responsible for the interradicular pathological bone resorption observed following pulpal necrosis in primary molars.

 



Survey of Professional Burnout and Depression among Pediatric Dentists in the United States

Dr. Leena Chohan, MSc Candidate, Faculty of Dentistry, University of Toronto

Committee Members: Dr. H Nainar, Dr. C Dewa, Dr. W El-Badrawy


Objectives: 1) To assess the prevalence of occupational burnout and depression among pediatric dentists in the United States and 2) To explore for differences in the prevalence of burnout and/or depression by gender, age, marital status, practice type, geographical location, number of years in practice, and number of hours worked per week.

 

Methods: A self-administered online anonymous survey was sent to all active members of the American Academy of Pediatric Dentistry residing in the United States. Survey Monkey® was used to administer the 37-item online survey. Questionnaire items consisted of three domains: demographic information (7 items); the Maslach Burnout Inventory (MBI) (22 items), including the three dimensions of Emotional Exhaustion, Depersonalization and Personal Accomplishment; and lastly the Patient Health Questionnaire 8 (PHQ-8) (8 items).

 

Results:  A total of 4739 surveys were sent and resulted in 785 responses (response rate = 17%). Nine percent of respondents had occupational burnout based on high scores in 2 dimensions of the MBI, Emotional Exhaustion and Depersonalization. Seven percent of the sample had PHQ-8 scores indicative of depression. Preliminary analyses indicated that those practicing in a group practice were less likely to have Emotional Exhaustion. Those who practiced for 40 or more hours per week were more likely to have Emotional Exhaustion (p<0.05). Prevalence of burnout and depression were correlated.

 

Conclusions: A small but notable number of U.S. pediatric dentists had occupational burnout and depression.



Trends in Caries-Related Emergency Visits to a Paediatric Hospital

M.Sc. candidate: Dr. Molly Ehrlich, DMD

Committee Members: Drs. Edward Barrett, Michael Casas and Carlos Quiñonez


Objectives: The aim of this study was to determine the annual frequency of children who presented to a tertiary care pediatric hospital with a caries-related emergency complaint over a ten-year period. The secondary aims of this study were to determine the demographic characteristics of the families that presented, the types of caries-related emergency complaints, treatment provided and costs associated with treatment.

 

Methods: A retrospective review of the health records of all children who presented to SickKids with caries-related emergency complaints and were seen by a dental resident from January 1, 2003 to December 31, 2012 was completed. A visit for an emergency dental complaint seen within the ED was identified as a registration where the principal diagnosis at discharge was coded using the International Classification of Disease block code equal to K00-K14 (diseases of oral cavity, salivary glands and jaws). Eligibility was determined by reviewing the corresponding health. Records were reviewed and data abstracted on: patient demographics, presenting complaints, co-morbidity, dental treatments, final diagnosis and patient disposition. A cost analysis was provided by SickKids Decision Support Services.

 

Results: During the ten-year period, 2,020 children with caries-related complaints presented to the ED. Visit rates for caries-related complaints increased by 48% (P= 0.0049) over the study period. 68% of the patients were younger than 6 years. Of the 2,020 patients, 1,217 were seen by the dental resident. There were 276 admissions and 85 were treated under general anaesthetic. The mean cost of care within the ED was $248 (CND).  

 

Conclusions: Over the study period there was an increasing trend in caries-related ED visits to a pediatric hospital. EDs have become an important site for people with caries-related sequelae to seek urgent care, particularly for pre-elementary school age group. These visits utilize hospital resources with an average per visit cost of $248.

 


The “W5” of pediatric hospital dental emergencies: A quantitative and qualitative analysis


Dr. Jennifer Park 1*, Campbell, K2

 

1MSc. Candidate, Faculty of Dentistry, University of British Columbia, Vancouver, Canada; 2Faculty of Dentistry, University of British Columbia; Dept. of Dentistry, BC Children’s Hospital, Vancouver, Canada

 

 

Objective:  To explore factors contributing to a reported increase in emergencies presenting to the Department of Dentistry at BC Children’s Hospital over recent years by investigating the “who, what, when, where and why” of their hospital management.

 

Methods: A two-phase study incorporated quantitative (retrospective chart review) and qualitative (personal interview) elements. Phase 1 - Records of 300 emergencies from 2009 to 2013 were systematically selected and reviewed. Patient demographics; source of referral; time/day of visit; nature, scope and management of emergency; and follow-up care were analyzed (Pearson’s Chi-squared Tests and Odds Ratios). Phase 2 - Twenty-five interviews with parents of children who recently experienced dental emergencies were recorded and analyzed for common themes in reported factors/circumstances.

 

Results: Emergencies included dentoalveolar trauma (56.7%), dental pain (20%), swelling from advanced dental disease (13.3%), and ‘other’, unrelated to trauma or caries (10%). Common patients characteristics were: healthy, male, young age (<7 years old), proximity of residence to the hospital and low socioeconomic status. Primary source of referral was the emergency department; emergencies presented equally throughout the week. No immediate intervention was necessary for the majority of cases and follow-up with a community dentist was advised. Factors contributing to a parent’s decision to seek emergent dental care in a hospital included: perception of urgency; concern for their child’s well being; desire for reliable care by a reputable institution; limited understanding of dental disease and consequences of poor oral care; and financial and access to care barriers.

 

Conclusion: Dentoalveolar trauma and untreated advanced dental caries compel families to seek hospital-based dental emergency services. More aggressive efforts to improve awareness of the importance of early dental visits; development of curricula emphasizing management of anxious children and exposure to pediatric emergencies; and reinforcing the ethical responsibility of dentists to provide after-hours emergency care may help to reduce burden on hospital resources.

 

Acknowledgements: Project funding provided by British Columbia’s Children’s Hospital 2012 Telethon Projects Award.



A Retrospective Study of Stainless Steel Crowns as a Posterior Permanent Tooth Restoration Option


Dr. Alison Sigal

Year of Convocation: 2016

Degree: Master of Science, Department of Paediatric Dentistry, University of Toronto


Objectives: This retrospective cohort study was performed to assess the long-term clinical and radiographic outcomes of the stainless steel crown (SSC) as a posterior permanent tooth restoration option.


Methods: Study included 271 patients with at least one SSC restoration of their permanent posterior dentitions registered at the Mount Sinai Hospital’s Dentistry Clinic for Persons with Special Needs. All posterior permanent tooth restorations were documented accounting for 2623 restorations: 766 SSC, 1651 Amalgam, 204 Composite Resin, and 2 Glass Ionomer.


Radiographic analysis of SSC restorations included 61 patients, 127 bitewing (BW) and 118 periapical (PA) radiographs (59 pre and post SSC placement). BW films permitted electronic measurement of interproximal bone levels. Pre/Post-SSC PA films permitted assessment of periapical status utilizing the Periapical Index (PAI) Scoring Scale.


Results: The 10-year survival rate (95% CI) for SSC restorations was 82.6% (78.8%, 86.0%). The median follow-up was 5.1 years with a range of 0-33.1 years. 675 recorded as intact at final chart assessment with 91-recorded true failures (Recementation: 2, Replacement: 33, Extraction: 56). Breakdown of diagnoses at time of failure included: Caries: 8, Loose/Lost SSC: 2, Pulpal Necrosis/pathology: 21 and Other: 25.


The average alveolar bone height recorded from distal and mesial sites of SSC restorations respectively were 1.40mm (0.53 – 3.78mm) and 1.36mm (0.53 – 2.84mm). 92.1% (117/127) of distal and 93.7% (119/127) of mesial sites recorded as healthy, non-resorbed. All 59 Pre-SSC PA had healthy periapical scores (fifty: 1, nine: 2). Post-SSC PA; 13 SSC restorations had PAI score changes recorded over an average duration of 8.4 years (1 – 29.1 years);seven changed from 1 to 2, six from 2 to 1, all consistently representing healthy periapical structure.


Conclusion: A stainless steel crown restoration is an effective long-term treatment option for the permanent posterior dentition with negligible effects on the surrounding periodontal alveolar bone heights and periapical status.



Professional Uncertainty in Providing Dental Care for Special Needs Children

 

Dr. Shan Sun S1*, Bush HM2, Harrison R1, Poon B3, Mathu-Muju KR1

 

1Department of Oral Health Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, Canada; 2
Department of Biostatistics, College of Public Health, University of Kentucky, Lexington, U.S.A.; 3School of Population and Public Health, Faculty of Medicine, University of British Columbia, Vancouver, Canada

 

Objective:  The aim of this study was to determine whether scientific (knowledge base), practical (clinical infra-structure) or personal (sense of social justice) sources of uncertainty among British Columbia general dentists posed the greatest barriers to their ability to treat children with special health care needs (CSHCN).

 

Methods: A 74-item self-administered electronic questionnaire was distributed to a random sample of 1200 general dentists registered with the British Columbia Dental Association. Variability in clinical practice (examine, examine and refer, refer) was assessed using three case scenarios featuring CSHCN with a 1) behavioral difficulty (autism spectrum disorder), 2) physical disability (bleeding disorder) or 3) combination (cerebral palsy). Respondents were asked to use a five-point Likert-type scale to rate uncertainty levels from scientific, practical and personal sources in each case scenario. One-sample t-tests were used to compare differences between examination/refer for examination and treat/refer for treatment group pairs. All items in the scientific, practical and personal domains were tested using multivariate analyses (logistic regression) for all three cases. Data was analyzed and classified based on a novel taxonomical approach.

 

Results: The response rate was 20.2% (n=226). A higher percentage of dentists were willing to examine and treat a child with a bleeding disorder (59.7%) or cerebral palsy (63.0%) compared to a child with autism (54.5%). Among those who would refer, the most significant reported sources of uncertainty in general are scientific (knowledge of management, ability to diagnose disease) and practical sources (staff training, inadequate facilities, busy practice).

 

Conclusions: While the majority of general dentists showed interest and desire to provide care for CSHCN, scientific and practical uncertainties are significant factors affecting their ability to provide care.  Recognizing the presence of uncertainty in dental care can inform policy changes to help dentists either decrease reducible uncertainties or cope with those that are irreducible. Implementation of increased undergraduate curriculum hours and hands on experience with CSHCN as well as expanded coverage of public and private dental benefits may help reduce barriers to care for CSHCN, in particular for those with conditions such as autism spectrum disorder.

 

Acknowledgements: Children with Special Health Care Needs Grant #F13-00854, British Columbia Dental Association.


 






 

2014 Abstracts, Montreal, Quebec 



 

Evaluating Parents' and Pediatricians' Awareness of the Cariogenicity of Pediasure                                                                       Emily Lin Jun Chen, D.M.D., Janna Danbe, D.M.D., Nuntiya Kakanantadilok, D.M.D.
Montefiore Medical Center, Bronx, New York, U.S.A.       

Objectives:
1) Determine reasons why parents give Pediasure (nutritional supplement) to their children,
2) Investigate how parents use this product, 
3) Determine what information pediatricians provide to their patients for use of the nutritional supplement,
4) Evaluate pediatricians' knowledge of the cariogenicity of the nutritional supplement.

Methods:     
A survey was administered to the parents of patients at the Montefiore Medical Center Pediatric Dental Clinics, who reported their child’s usage of the nutritional supplement. The goal of the survey was to evaluate the parents’ knowledge of the nutritional supplement as a potential caries risk factor, similar to other sugary beverages. The questionnaire helped determine why patients were using the nutritional supplement and what type of professional anticipatory guidance they had received regarding its use, if any. Similarly, a survey was administered to pediatric medicine residents and pediatricians at Montefiore Medical Center (who treat the same patient population) to determine what information and or instructions were given regarding the consumption of the nutritional supplement.

Results and Conclusions:
This study demonstrated the need to discuss nutritional supplement usage at dental visits as part of routine anticipatory guidance, in an effort to reduce patient’s dental caries risk.  Neither parents nor pediatricians were aware of the relative sugar content of the nutritional supplement compared to other beverages known for their high sugar contents. Parents were unaware that this nutritional supplement is cariogenic, and they were giving the nutritional supplement because they were concerned about their child not eating enough. They did not routinely discuss the usage of the nutritional supplement and caries prevention with their child’s pediatrician. Pediatricians did not routinely provide oral hygiene counseling for patients using the nutritional supplement. Pediatricians should include oral hygiene counseling and discuss the cariogenicity of the nutritional supplement, as part of their routine anticipatory guidance. 73% of parents who purchased the nutritional supplement without the pediatrician’s recommendation, were willing to discontinue product usage, when informed of the cariogenicity.

Changes in parental behavior depend on the pediatric dentist providing anticipatory guidance that includes nutritional counseling.  Dentists must ask about the use of these products.


       
Trends in Caries-Related Emergency Visits to a Paediatric Hospital

Molly Ehrlich, DMD
Committee Members: Drs. Edward Barrett, Kathy Boutis, Michael Casas and Carlos Quiñonez

Objectives:
The aim of this study was to determine the annual frequency of children who presented to a tertiary care pediatric hospital with a caries-related emergency complaint over a ten-year period. The secondary aims of this study were to determine the demographic characteristics of the families that presented to the hospital, the types of caries-related emergency complaints, the treatment provided and the costs associated with providing this care.

Methods:
A retrospective review of the health records of all children who presented to SickKids with caries-related emergency complaints from January 1, 2003 to December 31, 2012 was completed. Records were reviewed and data abstracted on: patient demographics, presenting complaints, co-morbidity, dental imaging, dental treatments, final diagnosis and patient disposition.  Patients seen in 2007- 2012 had additional information collected including wait times (total time spent in the emergency department), Comprehensive Ambulatory Classification System (CACS) grouping, Resource Intensity Weight (RIW), catchment area and direct and indirect costs associated with care. Time series analysis will be used to explore trends and patterns within the data. Descriptive statistics will be calculated, including the mean and standard deviation for quantitative measures such as age, neighborhood income quintile and deprivation index quintile. Frequencies of chief complaints, diagnoses and treatments rendered will be calculated and compared by year of presentation. Mean cost of treatment, cumulative total costs and total time spent in the emergency department will be calculated and compared by year of presentation.

Results:
The results are pending.  Data collection is currently underway and planned to be completed by August, 2014.

Conclusions:
Conclusions are pending.
      
      

Oral Inflammatory Load as a Risk Factor for Spontaneous Preterm Birth in Women at Risk of Preterm Delivery


Marie-Lyne Gosselin, DMD
Supervisor: Dr. Michael Sigal, Dr. Howard Tenenbaum, Dr Michael Glogauer
Committee Members: Dr Wendy Whittle, Dr Amir Azarpazhooh, Dr Michael Goldberg
       
Objectives:
The primary aim of this study was to explore the possible association between oral inflammatory load  (OIL) and spontaneous preterm birth (PTB) in pregnant women who are at risk of preterm delivery by evaluating their exposure to indicators of OIL. This study also aimed to compare oral neutrophils counts in pregnant women at risk of spontaneous preterm delivery with oral neutrophil counts in pregnant women with no foreseeable risk of spontaneous preterm delivery.
       
Methods:
Following specific inclusion and exclusion criteria, pregnant women at risk for PTB were recruited to participate in this prospective cohort study. The cells from oral rinse samples provided by the participants were stained with acridine orange, and neutrophil counts (primary exposure variable), were carried out visually by using a fluorescence microscope and a hemocytometer and via spectroscopy. Traditional and non-invasive assessment measures of periodontal health were also recorded and a blood sample was collected to assess the MMP-9 and the fetuin (Ahsg) serum level (secondary exposure variables). Pregnancy outcome along with demographic, dental and medical data were collected using a questionnaire, the antenatal dental chart, the delivery records and a post-delivery phone call questionnaire.

Results:
The results are pending. Statistical measures of risk will be calculated to measure the risk of PTB following the exposure to the observed variables. To control for confounders, a multiple logistic regression analysis will be executed.

Conclusion:
This study will bring about a deeper understanding of the possible relation between OIL, related to periodontal inflammation that could include either or both periodontitis and gingivitis, in pregnant women at high risk for PTB and overall birth outcomes.  By relying principally on non-invasive, fast and straightforward tools for assessment of OIL, this approach could be used, even by those without dental training, to identify women at  risk for PTB.

 

 

COMPOSITE BOND STRENGTH OF ONE AND TWO - STEP ADHESIVE SYSTEMS USED FOR RESTORATIONS ON PRIMARY TEETH USING VARYING ACID ETCH APPLICATION TIMES.


Brad Klus, University of Manitoba
The objective of this study was to determine whether the composite bond strength acquired using a single step self-etching bonding system is as or more effective when compared to the two step etch-rinse-bond system at clinically relevant in-vitro standards.


A total of 80 extracted human deciduous with at least one intact smooth surface were collected with parental consent. Collected teeth were randomly assigned to one of four treatment protocols (n=20): single step self-etch (Adper Prompt L-Pop, 3M ESPE), two step etch (15s)-rinse-bond (Optibond Solo Plus, Kerr), single step self etch (Adper Prompt L Pop, 3M ESPE) with 30s pre-etch, and two step etch (30s)-rinse-bond (Optibond Solo Plus, Kerr). A composite cylinder of uniform shape was bonded to each tooth using the designated adhesive system and specimens were tested with a universal testing machine. Descriptive statistics and statistical analysis was performed.


Median shear bond strengths for all specimens, regardless of treatment group, ranged from 3.25 MPa to 43.13 MPa. These values are above suggested minimum clinical required values of 3MPa. A Kruskal-Wallis analysis between treatment groups found statistical significance (p<0.05) for shear bond strength between the groups and both one step system protocols, had higher mean and median shear bond strength values than the two step systems.


An adhesive remnant index (ARI) was analyzed to confirm uniform adhesive fracture between all four treatment groups. Both a Fisher’s exact test, and a Hantel-Haenszel statistic found no significant difference (p<0.05) between the samples.


Based on these findings we concluded that:
1. The ARI score for all treatment groups was not statistically significant, suggesting that the type of bond breakage was consistent regardless of adhesive system used.
2. Both Optibond Solo Plus and Adper Prompt L-Pop systems achieve adequate shear bond strengths as described by current literature.
3. The use of a one-step system to save chair time and aid in patient behavior management may be clinically useful


 

Effect of anticipatory guidance on the presence of cariogenic bacteria in preschool children
       

Nick Lekic, University of Manitoba

Objectives: This study was designed to address whether or not the level (high or low) of Streptococcus mutans in the saliva of preschool children can be used as an indicator of caries risk. 


Material and Methods: Levels of Streptococcus mutans was assessed in saliva of 100 preschool children, before and approximately 6-months after receiving a health promotion intervention known as anticipatory guidance. The S. mutans bacterial level was assessed using an immunoassay system (Saliva-Check MUTANS) based on monoclonal antibody technology. Bacterial counts were determined at baseline as well as at a six month recall examination. Obtained data was analyzed using SPSS 20.0 for Windows to report frequencies and to look for trends and associations between the dependent and independent variables. Bivariate analysis (ANOVA, Chi Square/Fishers/McNemar exact test) was used to identify associations between variables. 


Results: The main finding of this study was that higher levels of Streptococcus mutans were associated with higher caries prevalence at baseline, and caries incidence at follow-up. Furthermore following anticipatory guidance, the levels of Streptococcus mutans were reduced at the subsequent follow-up examination, approaching but not reaching statistical significance, and caries incidence was significantly lower in subjects demonstrating low Streptococcus mutans levels.


Conclusions: Results from this study have shown that anticipatory guidance, offered to caregivers and children at an initial examination, led to a reduction in the proportion of children with high Streptococcus mutans levels upon recall six months later. Children with low Streptococcus mutans levels were also less likely to develop new dental caries. These findings suggest that Streptococcus Mutans counts could be used to assess caries risk and encourages clinicians to provide anticipatory guidance to their patients to help avoid the development of new caries.

 


        “But they stole her teeth.”  Developmentally disabled adults seek dental care

 

Salmasi A*, Harrison R, Brondani M, Rush J

Department of Oral Health Sciences, Faculty of Dentistry, The University of British Columbia, Vancouver


Objectives: Dental services for children and adolescents with special health care needs, such as developmental disabilities, are reasonably accessible in tertiary care hospital dental departments and in the private offices of pediatric dentists.  However, once these young people become  adults, accessing dental care is often problematic.  This qualitative study explored the experiences of adults with developmental disabilities (AWDD) accessing dental services in metro Vancouver. 


Methods: This research used a qualitative, deductive approach.  Recruitment of participants was facilitated by AWDD service organizations and family support groups. Time was devoted to engaging and building relationships with participants before beginning the research.  Consent was obtained from each participant. The focus groups were guided by open-ended questions, audiotaped and then transcribed.  Each focus group lasted, on average, forty minutes. Participants were either “self-advocates” (AWDD who speak or act on behalf of themselves or others on issues that affect people with disabilities) or caregivers (usually parents). Each transcript was read, re-read and coded.  These codes were organized into categories and finally into domains.


Results: Five focus groups with twenty participants were conducted. Seven main domains relating to the experiences of AWDD self-advocate and their family members with dental care providers were identified. These domains were communication, trust, respect, financial issues, transitional services, waiting times and, finally, what makes for a “positive dental experience”.


Conclusions:  The cost of dental care and the need for enhancing government dental benefits for AWDD were concerns expressed primarily by family members. However, problems with communication between dental professionals and AWDDs and respect for the personal autonomy of AWDD  were identified by self-advocates and their carers as issues of concern in the quest for dental care. Ideas for a more positive dental experience were suggested with the hope that these ideas will eventually be communicated to dental providers.


Acknowledgements:  Project funded by BC Dental Association and Canadian Fund for Dental Education.

       

Esthetic Crown Options for the Primary Dentition within Post-Doctoral Residency Programs


Bradford Scheideman, DMD, Jacobi Medical Center

Purpose: To compare the attitude, usage and training of esthetic, full-coverage restorative treatment options in the primary dentition among pediatric dentistry residents and program directors.


Methods: Utilizing an email list from the AAPD, two questionnaires were sent to 907 pediatric dentistry residents and 108 pediatric dentistry program directors. Both surveys investigated the utilization, the learning opportunities provided to the residents, the perceived limitations, and the personal experience of different esthetic, full coverage restorative treatment options. Results were analyzed using standard accepted statistical analysis.


Results: Most pediatric dentistry residencies offer a variety of esthetic, full coverage primary restorative options for anterior teeth, while the majority of programs do not offer any esthetic restorative treatment options for posterior teeth. Residents and dentists both agree that esthetics in the primary dentition are important to parents and pediatric dental residents. There are many barriers to new esthetic primary restorative treatment options. Barriers to zirconia crowns (ZC) include cost, retention, lack of research, lack of personal knowledge/experience, fracture, removal of excess tooth structure, and excess time to place. The major barriers of preveneered SSCs (PVSSC) include patient dissatisfaction and risk of fracture.


Conclusion: Pediatric Dentistry Residencies are adapting to a more esthetic approach for full coverage primary dental restorations. There is a discrepancy between what the director’s state the residents are able to offer in terms of esthetic restorations and what the residents provide to the patients. There is also a discrepancy between the residents’ clinical training and the reported clinical experience in esthetic restorations. The majority of residents are able to learn about PVSSC from faculty members but rely on manufacturer prepared material to educate the residents on ZC. There are several barriers to ZC that need to be addressed before they are universally incorporated into routine restorative procedures by pediatric dentists and residencies.
               

Life-long tooth replacement in the leopard gecko (Eublepharis macularius)
      
Wong, Andrew C.1 Grieco, Theresa M. 1 Richman, Joy M.1

Life Sciences Institute, Faculty of Dentistry, University of British Columbia, Vancouver, Canada

Background: The tooth replacement pattern of the human dentition is characteristic in terms of timing however the understanding of what controls the transition from primary to permanent dentition is lacking. Moreover it is not clear why humans can only replace their teeth once while other animals such as reptiles can replace their teeth throughout life. One potential pathway involved in tooth replacement is the Wingless signalling pathway (Wnt), which leads to uncontrolled budding of supernumerary teeth Gardner’s syndrome in humans.


Objectives: 1) To develop a reptile model, the leopard gecko, in order to study tooth replacement in real-time in vivo. 2) To measure the effect of LiCl, an activator of Wnt signaling, on tooth replacement in longitudinal studies.


Methods: Upper dental arch wax bites of 3 adult leopard geckos were taken weekly. The present/missing teeth were recorded over an 8 month period. The palate was injected bilaterally with LiCl or the control, Sodium Chloride (NaCl), at certain intervals. Post-euthanization, the upper and lower arches were evaluated using Micro CT imaging and with histology.

 

Results: The average replacement frequency per tooth was 7 weeks and there were 42 teeth per quadrant. Slower cycling teeth were interspersed between faster cycling teeth. A posterior-to-anterior wave of replacement emerged but was inconsistent. Additionally, there was limited replacement symmetry between right and left sides. LiCl disrupted the replacement pattern at varying times as the posterior-to-anterior waves became irregular.


Conclusions: Posterior-to-anterior waves of replacement present at certain intervals but repeating coordination of replacement is not readily apparent. LiCl caused irregularity in the replacement wave suggesting Wnt signaling may regulated the natural process of  tooth replacement.


Acknowledgements: Supported by Faculty of Dentistry Research funds and an NSERC Discovery grant to JMR (RGPIN 326908)                             
    
       
Quantifying facial morphogenesis in 3D using Optical Projection Tomography

       

Woo, JM2*, Richman, JM1,2
1Life Sciences Institute, 2Faculty of Dentistry, Division of Pediatric Dentistry. University
of British Columbia


Objectives: In order to study abnormal facial development, reference standards of normal development are required. It is challenging to obtain 3D data on early embryos, since they are comprised of non-differentiated tissue. We used optical projection tomography (OPT) (Bioptonics, UK), which images transparent specimens with UV light. Here we used carefully staged chicken embryos to measure facial morphogenesis over time.

 

Methods: Chicken eggs (n=32) were incubated for 3.5-6 days (stage 20, 24, 28, 29). Embryo heads were fixed in 10% formaldehyde, embedded in agarose blocks, dehydrated in methanol, and then cleared in Benzyl Alcohol Benzyl Benzoate 2:1. Embryos were scanned with the OPT, images were reconstructed, and then the head was digitally resliced in the frontal plane using NRecon and CTan. Resliced files were imported into Amira software, and facial prominences were outlined, and isosurfaces were created. Volumetric measurements were assessed using Amira. Landmarks were applied to the outer surface of each prominence using Landmark. The landmarks were then superimposed from different embryos using MorphoJ, whereby they underwent Procrustes Superimposition (PS), Principal Component Analysis (PCA), Canonical Variate Analysis (CVA), and Discriminant Function Analaysis (DFA).


Results: Traditional morphometrics revealed that the greatest amount of growth was a 24-fold difference in volume of the lateral nasal prominence between stages 20 and 29, followed by the maxillary, mandibular, and frontonasal mass. The ratio length/width shows that there was a 3-fold difference in the frontonasal mass between stages 20 and 29. Geometric morphometrics revealed that embryonic facial prominences grow isometrically until stage 24 except the maxillary prominence which grows till stage 28. Afterwards, facial prominences grew allometrically. Shape changes were observed in all three axes. The frontonasal mass narrowed mediolaterally, and lengthened superioinferiorly and proximodistally. The lateral nasal and maxillary prominences both grew more proximodistally and mediolaterally, and had minimal growth superioinferiorly. The mandibular prominence grew mainly superioinferiorly, and had minimal growth mediolaterally and proximodistally.


Conclusion: Embryonic chicken facial prominences undergo allometric growth. Each prominence varies in dimensional changes with respective stage, with the frontonasal mass and mandibular prominence having the greatest dimensional change.


Acknowledgements: This work was funded by Faculty of Dentistry research funds and CIHR operating grants to JMR.




T


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