National Dental Centre Singapore Research Articles

Dental surgery assistant trainees’ perceptions of mental well-being and working in the dental clinic

Introduction: An online survey was conducted on 16 National Institute of Technical Education Certificate (NITEC) Dental Surgery Assistant (DSA) trainees in National Dental Centre Singapore to find out their perceptions and understanding of mental well-being. Methods: The 43-item survey included (i) Psychological General Well-being Index (PGWB) with 22 items based on 6 domains (anxiety, depression, positive well-being, self-control, general health, and vitality); (ii) 5 items on mental health knowledge; (iii) 4 items on lifestyle; and (iv) 12 items on perceptions of mental well-being and working in the dental clinic. Responses were collated for descriptive analysis and Cronbach’s alpha analysis was done for internal consistency for Likert scale items. Results: The average PGWB score was 61.5 (range 18-89). Fourteen trainees (75%) indicated they were feeling depressed and 31.2% of trainees felt under stress in the past month. The majority (81.3%) of trainees recognised the role of exercise in maintaining mental health and 75% of trainees were able to differentiate between sadness and depression. However, 56.3% and 87.5% of the trainees incorrectly answered that mental and psychological disorders are not preventable conditions and mental disorders are caused by a wrong way of thinking respectively. The Cronbach’s alpha on PGWB ( = 0.87) and trainees’ perception of working in the clinic ( = 0.76) revealed good internal consistency. Conclusion: The PGWB scores and survey analysis indicate there is a knowledge gap about mental health and the need to improve mental well-being in this cohort of NITEC DSA trainees. Keywords: Mental Well-being, Dental Surgery Assistant Trainee, Psychological General Well-being Index

Orthodontic traction of impacted teeth involving gold chain bonding: A retrospective study on success rate and associated factors

Objectives: This study aims to investigate the success rate of orthodontic traction of impacted teeth using the gold chain bonding (GCB) procedure. Material and Methods: Orthodontic patients underwent the GCB procedure at the National Dental Centre Singapore (NDCS) between 2014 and 2021. The sample comprised 495 teeth from 421 patients (238 male, 257 female; median age 14; range 7 -38 years). The historical records of these patients’ orthopantomograms and electronic medical records were reviewed to collect data on age, gender, ethnicity, tooth type, and surgical re-intervention. The success rate was calculated and compared using chi-square test and logistic regression analysis. The level of significance was set at P < 0.05. Results: The overall success rate of the GCB procedure was 93.3%. There was no significant difference in the success rates between male (92.9%) and female (93.8%) patients (P = 0.779) or between Chinese (93.2%), Malay (94.4%), and Indian (91.7%) patients (P = 0.664). Younger patients have significantly higher odds of success than older patients (P = 0.0099, odds ratio = 0.897). The success rate was highest for the upper lateral incisors (97.4%) followed by upper central incisors (94.7%). The success rate of surgical re-intervention of the GCB procedure was 69%. Conclusion: Gold chain bonding is a highly predictable procedure for orthodontic treatment of impacted teeth with a high success rate especially in younger patients. Gender and ethnicity do not significantly affect the success rate.

Orofacial Infections seen at A Specialist Dental Centre - A retrospective analysis of causative microbes and their antibiotic sensitivities over 6 years

ObjectiveWith increasing incidence of resistant microorganisms, it is beneficial to consider whether there has been a shift in spectrum and resistance profiles of microbes implicated in orofacial infections. This will help guide empirical antimicrobial choice in the treatment of such infections. The main objectives of this study were to investigate any change in trends of causative microbes associated with orofacial infections and their antibiotic sensitivity over the past 6 years and trends in prescription of empirical antibiotics in a specialist dental centre in Singapore. MethodsThis retrospective study was performed on outpatients at the National Dental Centre Singapore (NDCS) with orofacial infections from 1st Jan 2012 to 31st Oct 2017, requiring biological samples to be taken for culture and sensitivity (C&S) testing. ResultsThere was a statistically significant increasing trend in the proportion of Streptococcus spp. cultured from orofacial infections (p = 0.04). Over 6 years, 100 % of aerobes tested against Co-amoxiclav were deemed sensitive. ConclusionBeta lactams appear to have good coverage against most microbes implicated in orofacial infections, especially Co-Amoxiclav, and would be a good first-line empiric antibiotic for orofacial infections in the absence of beta-lactam allergy.

Dental education continuity during the COVID-19 pandemic – Experience at National Dental Centre Singapore

Introduction: The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused the COVID-19 pandemic which started in 2020. This resulted in a disruption to educational activities across the globe. Dental education, in particular, was affected because of its vocational nature where learners come into close contact with patients when performing dental procedures. Methods: This is a narrative review with no research data analysis involved. Results: Social distancing measures introduced to curb the spread of the infection revolutionised the advancement of online education as the virtual environment is a safer place to conduct teaching compared to face-to-face teaching. In this article, we share our experience at the National Dental Centre Singapore (NDCS) in ensuring the safety of our faculty and learners when conducting didactic and clinical education during the pandemic. Didactic lectures were conducted in the virtual environment via synchronous and non-synchronous teaching. Essential clinical education was conducted in small groups with safe management measures in place. In addition, we provide guidelines to highlight the importance of meticulous planning, thorough preparation, and seamless delivery in conducting effective synchronous teaching. Conclusion: Safe management measures put in place to ensure the well-being of our faculty and learners can ensure dental education continuity during the pandemic.

Prevalence of Class I, II and III skeletal relationships and its association with dental anomalies in an ethnic Chinese orthodontic population

Objectives: To investigate the prevalence of skeletal Classes I, II and III in a Chinese orthodontic population, and determine its association with the prevalence of dental anomalies. Methods: This retrospective cross-sectional study was conducted on 2508 ethnic Chinese orthodontic patients aged 14 to 25 years who attended the Department of Orthodontics at the National Dental Centre Singapore. Radiographs, photographs and clinical records of the study sample were examined for the prevalence of dental anomalies in the permanent dentition, excluding third molars. The anteroposterior skeletal relationship was determined based on the A point–Nasion–B point angle measured from the lateral cephalogram, whereby Class I: A point–Nasion–B point = 3.6° ± 2.5° (1 standard deviation) that is 1.1° to 6.1°; Class II: A point–Nasion–B point greater than 6.1°; Class III: A point–Nasion–B point less than 1.1°. Logistic regression was used to determine the association between the anteroposterior skeletal relationship and the occurrence of various dental anomalies. Results: The prevalence of the anteroposterior skeletal relationship was: 49.5% Class I; 23.1% Class II; and 27.4% Class III. Class III patients had significantly lower odds of impacted teeth compared to Class I patients (odds ratio 0.608, 95% confidence interval 0.463–0.798; P=0.00009). There was no significant difference in the occurrence of the anomalies among the various anteroposterior skeletal types. Conclusions: The occurrence of impacted teeth was lower in Class III than Class I, while no significant differences were noted for hyperdontia, hypodontia, peg-shaped upper lateral incisors, transposition and double teeth. The occurrence of all investigated dental anomalies had no significant difference between Class II and Class I.

A Risk-Based Approach to the COVID-19 Pandemic: The Experience in National Dental Centre Singapore.

The emergence of a highly infectious coronavirus strain, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has led to a major global public health emergency. The increasing number of infected cases and fatalities worldwide forced several countries into lockdown in a bid to control virus transmission. The practice of dentistry is considered high-risk due to the generation of aerosols associated with most dental procedures, and healthcare professionals must take appropriate precautions whilst working in this challenging environment. This review aims to provide an overview on transmission routes and shares a risk-based approach to coronavirus disease 2019 (COVID-19) in a specialty tertiary center. Risk assessment and mitigation focussed on staff and patient safety, adopting a wide safety margin, and responding dynamically to the level of risk at the workplace. As the severity of the pandemic depends on many still-unknown factors and shows little sign of abating, the routine practice of dentistry will continue to be disrupted in the near future. We describe a color-coded framework to maximize safety and to minimize disease spread. Areas covered include healthcare team management, personal protective equipment, clinical work, and dental education. Guidelines in each category change with the corresponding severity of the situation, and we believe it will be useful for the safer practice of dentistry in this current climate and can be modified for future similar disease outbreaks.

The Role of Dentists in COVID-19 Is Beyond Dentistry: Voluntary Medical Engagements and Future Preparedness.

The emergence of the highly infectious novel coronavirus SARS-CoV-2 has led to a global COVID-19 pandemic. Since the outbreak of COVID-19, worldwide healthcare systems have been severely challenged. The rapid and explosive surge of positive cases has significantly increased the demand for medical care. Herein we provide a perspective on the role dentists can play in voluntary medical assistance and future preparedness for a similar pandemic. Though dentists and physicians have different scopes of practice, their trainings share many similarities. Hence, dental professionals, with their knowledge of basic human science and sterile surgical techniques, are an invaluable resource in the COVID-19 pandemic response. Overall, it is commendable that many dentists have risen to the challenge in the fight against COVID-19. For example, in Singapore, National Dental Centre Singapore (NDCS) deployed dental clinicians as well as volunteers from research laboratories to screen for suspected cases, provide consultations as well as conduct swabbing operations. Dental practice will be considerably changed in the post-COVID-19 era. There is a greater need to have refresher courses for practicing dentists on new infection control strategies. Moreover, the curriculum in dental schools should be expanded to include competencies in pandemic and disaster relief. In addition, voluntary medical work should be made a part of the community dentistry curriculum. This volunteerism will leave a positive impact on developing the careers of young dentists. Hence, the contribution of dentists beyond dental practice in this pandemic situation will be appreciated by future generations.

Influence of periodontal maintenance and periodontitis susceptibility on implant success: A 5-year retrospective cohort on moderately rough surfaced implants.

To investigate the effect of defined versus undefined periodontal maintenance after implant therapy on the prevalence of peri-implant complications. Two hundred patients who underwent dental implant therapy in the National Dental Centre Singapore (NDCS) from 2005 to 2012 were recruited. One hundred patients had regular periodontal maintenance (defined maintenance programme group, DMP), and the other 100 patients had no documentation of periodontal maintenance (undefined maintenance programme group, UMP). Full-mouth bleeding scores (FMBS), periodontal probing depths (PPD) and peri-implant probing depths (PiPD) were evaluated within 6months of prostheses delivery (T0 ) and at re-examination (T1 ). Peri-implant bone level changes were analysed radiographically. The mean follow-up time was 6.8years. Five out of 289 implants were lost (cumulative survival rate=98.3%). 6.0% of DMP patients and 20.0% of UMP patients had peri-implantitis (p=.003). Peri-implantitis was defined as bleeding on probing, increase in PiPD and peri-implant bone loss≥0.5mm. At the implant level, 4.0% of the DMP group implants and 17.2% of the UMP group implants were diagnosed with peri-implantitis (p=.0003). One implant in the DMP group and 13 implants in the UMP group had bone loss≥2mm (p<.0001). Multivariate regression showed that absence of regular maintenance (OR=0.24, p=.003) was significantly associated with peri-implantitis. Regular periodontal maintenance was associated with a lower prevalence of peri-implantitis and peri-implant bone loss. Patients with treated periodontitis without regular maintenance after implant placement were at higher risk for developing peri-implantitis.

Interceptive orthodontic treatment in Singapore: A descriptive study

Background: The benefits of interceptive orthodontic treatment have always been a subject of much debate, and it is understandable that clinicians are confused about how to advise parents of potential interceptive orthodontic patients. Objective: The aim is to study the treatment outcomes of interceptive orthodontics associated with different appliances. Demographic information on patients presenting for interceptive treatment, prevalence and types of dental conditions treated, types and frequency of appliances used, treatment duration and the number of visits taken were also investigated. Methods: This study involved analyzing records of interceptive orthodontic patients seen at the National Dental Centre Singapore from January 2011 to December 2017. Treatment outcomes were divided into success, improvement and failure according to pre-determined treatment objective parameters. Results: A total of 1324 patient records (654 females, 670 males) were studied, with an average age of 10.6±1.9 years. The most common dental condition seen was the anterior crossbite while the most common interceptive orthodontic appliance used was the bite plate. Average treatment duration was 10.8±6.8 months (9.8±9.2 visits) for fixed appliances, 7.5±6.5 months (6.9±3.4 visits) for removable appliances and 10.8±3.2 months (12.6±3.3 visits) for a combination. Interceptive orthodontic treatment had an overall success rate of 75.5%, improvement rate of 9.5% and failure rate of 15.0%. The most common reason for failure was attributed to non-compliance. Conclusion: The data above shed light on interceptive orthodontic treatment in an Asian population and gives useful information for primary care clinicians to provide for concerned parents.

Impact of pain-related temporomandibular disorders on jaw functional limitation, psychological distress and quality of life in postoperative class III East Asian patients.

This cross-sectional study determined the prevalence of painful TMD and its impact on jaw function, psychological status and oral health-related quality of life (OHRQoL) in postoperative Chinese patients. It also assessed factors influencing OHRQoL of these patients. Subjects were recruited from the National Dental Centre Singapore dentofacial deformity registry. Invitations to participate in the study were sent to patients who sought treatment from March 2011 to November 2017. Patients who consented were directed to an online link to complete a series of questionnaires based on the Diagnostic Criteria for TMD (DC-TMD) and the orthognathic quality of life questionnaire (OQLQ). The subjects (n = 99) had a mean age of 25.2 ± 6.0years and postoperative time of 29.4 ± 22.7months. 18.2% were found to suffer from pain-related TMD postorthognathic surgery and these patients (n = 18) had significantly higher median JFLS-8 score than those without TMD pain (p = 0.008). Time since surgery was significantly associated with OHRQoL (p = 0.00000026). Prevalence of painful TMD and psychological distress was low while prevalence of jaw functional limitation was moderately high in postoperative class III Chinese patients. Painful TMD impacted jaw function especially when subjects open wide enough to drink, yawn, talk and smile but had no significant consequence on psychological status and OHRQoL.

Orthodontic treatment in National Dental Centre of Singapore: Trends toward higher proportion of adult patients

Background Adult patients used to be daunted with the prospect of having fixed appliances to correct malocclusions. However, this has gradually changed and recent literature reported an increasing trend in adults receiving orthodontic treatment. To date, there has been no information regarding the trend of adult orthodontic patients in Singapore. Objective The objective of this study was to determine the changes in the proportion of adult patients seeking orthodontic treatment at the National Dental Centre Singapore (NDCS) from 2011 to 2017. Materials and Methods The study sample consists of all patients who commenced active orthodontic treatment from 2011 to 2017 at the NDCS. The data collected were analyzed for the number, gender, and proportion of adult orthodontic patients treated annually from 2011 to 2017. Linear-by-linear association test was used to test for any significant linear trend in proportion of adult orthodontic patients over the 7 years. Pearson’s Chi-squared test was used to test for any significant gender differences. Results There was a significant increasing linear trend (p = 0.001) in the proportion of adult orthodontic patients from 2011 to 2017. No significant difference (p = 0.770) between the proportions of male and female adults undergoing orthodontic treatment was found. The ages of adults undergoing orthodontic treatment ranged from 21 to 73 years old and majority (48.61%) of them was in the 21–25 years old age range. Conclusion There is a rising trend in adults seeking orthodontic treatment at the NDCS from 2011 to 2017. No statistically significant gender difference was observed in this rising trend.

Secondary dentition characteristics in an ethnic Chinese orthodontic population: A retrospective cross-sectional study.

To determine the prevalence of dental anomalies and its association with gender. This retrospective cross-sectional study was conducted using radiographs, photographs and clinical records of patients who attended the Department of Orthodontics at the National Dental Centre Singapore. Records of 2508 ethnic Chinese orthodontic patients aged 14-25years were examined for the prevalence of dental anomalies in the permanent dentition, excluding third molars. Statistical analyses were performed using SAS version 9.4 (SAS Institute Inc.). Logistic regression was used to determine the association between gender and the occurrence of various dental anomalies. Kappa coefficients were calculated to test for intra-examiner reproducibility. Statistical significance was set at P<0.05. Prevalence of dental anomalies was 5.7% hyperdontia, 11.1% hypodontia, 5.5% peg-shaped upper lateral incisors, 21.9% impacted teeth, 1.3% transposition and 0.4% double teeth. There was no significant gender difference in the occurrence of the anomalies except hyperdontia, with males having significantly higher odds of hyperdontia compared with females (odds ratio, 1.488; 95% confidence interval, 1.062-2.085; P=0.021). Occurrence of hyperdontia is greater in males than females, while no significant gender differences were noted for hypodontia, peg-shaped upper lateral incisors, impacted teeth, transposition and double teeth.

Residents’ expectations and perceptions of clinical teaching activities in National Dental Centre Singapore

Residents’ expectations and perceptions of clinical teaching activities in National Dental Centre Singapore

Nerve Injury After Surgical Excision of Mandibular Third Molars Under Local Anesthesia: An Audit.

Injury of the inferior alveolar nerve (IAN) sustained during surgical removal of an impacted lower third molar may cause paresthesia of the lower lip, chin, lower gingivae and anterior teeth. Lingual nerve (LN) injuries may result in ipsilateral paresthesia of the anterior two thirds of the tongue, mucosa of floor of mouth and lingual gingivae. A close anatomic relationship between the roots of the third molar and mandibular canal places the IAN at risk of damage. The primary aim of this retrospective audit was to ascertain the incidence of IAN and LN damage after mandibular third molar surgery in National Dental Centre Singapore. A secondary aim was to identify the contributory factors for the risk of IAN and LN nerve injury on the basis of the data collected. This retrospective audit included 1276 mandibular third molar surgical removals performed in the local anesthesia operating theatre (LAOT) at the National Dental Centre Singapore (NDCS) from April to December 2013. Data included patient details, clinical characteristics, and 1 week postoperative presence/absence of sensory alteration as reported by the patient. Summary of results- Out of 1276 third molar sites audited, 8 (0.62%) sites had altered sensation of the IAN and 1 (0.078%) had altered sensation of the LN at 1 week postoperative review. The incidence of IAN injury (0.62%) and lingual Nerve injury (0.08%) after one week from surgery in our audit was low compared to similar studies. This retrospective audit did not show any correlation of nerve injury to age, gender, race, site, angulation of tooth, grade of operator, removal of bone or tooth division. There was no single radiological sign associated with paresthesia, although the most common radiological signs were interruption of the canal line and darkening of the roots.

Perceived effectiveness of one-minute preceptor in microskills by residents in dental residency training at National Dental Centre Singapore

Background: The National Dental Centre Singapore (NDCS) has collaborated with the National University of Singapore’s Division of Graduate Dental Studies to provide supervised clinical training in the five dental specialties for residents since the early 1990s. Faculty were first introduced to the one-minute preceptor (OMP) in microskills through in-house workshops held from May to August 2014. Purpose: The aim of this study was to assess if a OMP faculty workshop impacts residents’ perceptions of clinical teaching in NDCS. Methods: First- and second-year residents were asked to rate their perceptions of the quantity and quality of clinical teaching, and the adequacy of the five OMP microskills performed by faculty before and one month after the OMP workshops. Data were analysed using descriptive statistics and non-parametric statistical tests. Results: A total of 37 NDCS clinical faculty participated in the OMP workshops and 34 residents participated in the pre- and post-workshop survey. The short-term impact of the OMP faculty workshop revealed minimal effect on residents’ perceptions of the clinical teaching in both quantity and quality. Conclusion: A one-time OMP workshop for faculty members does not substantially improve residents’ perceptions of the quality or quantity of clinical teaching. The results of this study indicate that the effort to improve clinical teaching by faculty must be a sustained effort. Future studies should investigate the barriers to faculty members’ performance of the OMP microskills.

A general survey on learners and faculty perspectives on educational activities held in the National Dental Centre, Singapore

Background: The National Dental Centre Singapore (NDCS) has been educating learners since the late 1980s. However, in this time, no formal feedback about these educational activities has been garnered from education stakeholders (comprising learners and faculty). Furthermore, no formal faculty development efforts to improve the educational activities have been done. Purpose: The aim of the study was to collect data from learners about the NDCS’s educational activities and the faculty’s attitude towards teaching. Methods: A survey was administered to 239 education stakeholders from May to July 2015. The survey on learners focused on learners’ perceptions on the importance and frequency of the One-Minute Preceptor (OMP) five-step microskills model of clinical teaching, and the quality and quantity of teaching overall. For faculty, the survey focused on their attitudes around teaching. Results: A total of 92 responses were received from learners. Learners perceived the OMP elements to be important (mean Likert scores ranged from 4.13–4.44 out of 5). However, they reported infrequent use of this teaching model by the faculty (range 3.06–3.50 out of 5). While learners reported quality and content of teaching to be adequate, they felt the number of clinical hours for teaching could be increased. The faculty reported positive attitudes towards teaching. Conclusion: This study provided educators with valuable feedback on the NDCS’s educational activities, identifying strengths and weaknesses of the programmes that they can work towards improving.

Influence of maintenance care in periodontally susceptible and non-susceptible subjects following implant therapy.

To compare the periodontal and peri-implant conditions of periodontally susceptible and periodontally healthy subjects under maintenance care for a period of at least 3years. Sixty periodontally susceptible patients (PSP) and 56 periodontally non-susceptible subjects (PHS) were treated with dental implants in the National Dental Centre Singapore (NDCS) and were maintained in a regular supportive periodontal care program for a mean of 6years. Full mouth bleeding on probing (BoP), full mouth probing pocket depths (PPD), implant loss, and absence of crestal bone loss were recorded at the time of prosthesis delivery and following a mean follow-up of 6years 2months. Although there were significant differences in the BoP and the percentage of subjects with tooth probing pocket depth ≥5mm between PSP and PHS at the time of implant prosthesis installation (T0 ), there were no significant differences between the two subject groups in the various parameters assessed at the follow-up visit (T1 ) (total number of teeth, percentage of subjects with implant probing pocket depth ≥5mm, percentage of subjects with implant probing pocket depth ≥ 6mm, absence of crestal bone loss, implant loss). Owing to a rigid regular SPT program, implants placed in PSP perform equally well when compared to implants installed in PHS over a mean period of 6-year follow-up.

Quality of Life Treatment Outcomes of Class III Skeletal Patients after Bimaxillary Osteotomies

Introduction: Bimaxillary osteotomies are commonly done to correct dentofacial deformities. Osteotomy at the LeFort I level and bilateral sagittal split osteotomy (BSSO) are commonly used in combination to treat patients with Class III skeletal dentofacial deformities. However, few studies are available which assess the treatment outcome measured in terms of quality of life (QoL) of Class III skeletal patients after bimaxillary osteotomies. This study aims to evaluate the long-term benefits of bimaxillary osteotomies, measured in terms of QoL outcomes of Class III skeletal patients at two (2) years post-surgery. Methods: This study was conducted at the National Dental Centre Singapore and selected patients were given 2 questionnaires each based on Oral Health Impact Profile (OHIP-14) and Orthognathic Quality of Life Questionnaire (OQLQ). The patients were told to report each question using a Likert-type scale and their perception for each question before and after surgery. Results: A total of 41 patients were recruited in this study, of which 23 were males and 18 were females. Their age ranged from 17 to 32 years old at the time of surgery and the median age was 20 years 2 months. All the patients in this study were Chinese. All the patients underwent LeFort I maxillary procedure in addition to BSSO setback surgery. The Wilcoxon Signed Rank test was used for evaluation of the statistics. There were significant changes to both OHIP-14 and OQLQ scores (p&lt;0.001) two-years post-operatively. All the OHIP-14 domains, functional limitation (p&lt;0.001), physical pain (p&lt;0.001), psychological discomfort (p&lt;0.001), physical disability (p=0.001), social disability (p&lt;0.001) and handicap (p&lt;0.001), were significantly decreased when compared to pre-surgical scores. The OQLQ domain scores, social aspects of deformity (p&lt;0.001), facial aesthetics (p&lt;0.001), oral function (p&lt;0.001), and awareness of facial deformity (p=0.013), were also significantly lower two-years post-operatively. Conclusion: Treatment outcomes measured in terms of QoL were significantly improved in Class III skeletal patients after bimaxillary osteotomies. The function, psychosocial and facial aesthetics improved significantly after surgery and these aspects continued well into two-years post-surgery. The inclusion of QoL as a routine treatment outcome measure in orthognathic surgery would be beneficial in clinical profiling of patients, decision making and evaluating the efficacy of the procedure. It could potentially be used to evaluate surgical complications, arising from orthognathic surgery, and its impact on QoL in patients. More studies would be required to establish its correlation in the future.

Case Series of Single Stage Immediate Implant Placements into Fresh Extraction Sockets of Mandibular Molars

Immediate implant placement into fresh extraction sockets of mandibular molars requires good case selection, detailed clinical and radiographic examination as well as adequate clinical experience and judgement. This paper describes a standard protocol adopted by a single Oral and Maxillofacial Surgeon from the Department of Oral and Maxillofacial Surgery, National Dental Centre Singapore, as applied to a series of four cases.

Modular Endoprosthesis for Mandibular Reconstruction — A Thematic Research Study at the National Dental Centre Singapore

Introduction: A thematic research project was undertaken by the National Dental Centre Singapore to study the feasibility of using a novel modular endoprosthesis for reconstruction of the mandible. Successful application of this technique potentially eliminates the need for a donor site. Methods: Three sub-projects done in a monkey model are presented. In the first two sub-projects, a titanium modular endoprosthesis was inserted in surgically created defects for reconstruction of the ascending ramus and condyle; and body of the mandible respectively. In the third sub-project, a polycaprolactone scaffold with calcium phosphate (CaP) surface coating modular endoprosthesis was used for reconstruction of the body of the mandible. The animals were sacrificed at three to six months. Microcomputed tomographic and histologic analyses were done. Results: At the time of sacrifice, signs of infection were present in a few animals treated either with the titanium or the polycaprolactone endoprosthesis for replacement of the body of the mandible. None of the animals who received the ascending ramus and condyle titanium endoprosthesis had an infection. New bone formation was noted around the stems of the titanium devices and inflammatory reaction was much reduced from three to six months. For the polycaprolactone device, more de novo bone formation was seen in the group using Human-BMP-2. Conclusion: The use of a modular endoprosthesis for mandibular reconstruction seemed to result in a physiologic replacement of the lost part of the mandible, although the biomechanics of the system need further evaluation so as to improve its long term stability.