PURPOSE: The purpose of this finite element analysis study was to evaluate stress and strain distribution patterns in 2-implant mandibular overdentures with different positions and angulations of implants under unilateral and bilateral loading.
MATERIAL AND METHODS: A cone beam computed tomography (CBCT)-based, 3-dimensional (3D) model of the mandible and an intraoral scanning-based 3D model of the denture were developed in the Mimics software program. A 3D model of a standard-sized implant with a low-profile overdenture attachment (LOCATOR) was developed in the Solidworks software program. Two implants were inserted in the 3D model of the mandible, with implants placed at different positions, 5, 10, 15, and 20 mm from the midline, and different distal angulations, 0-5, 0-10, 0-15, 5-5, 10-10, and 15-15 degrees (at 10-mm distance), in the 3Matics software program. Unilateral and bilateral vertical loads of 100 N were applied on the first molars in the ANSYS software program to record maximum von Mises stresses and strain values.
RESULTS: The stresses in the implants were maximum when placed at a 20-mm distance (4.18 MPa under unilateral and 4.2 MPa under bilateral loading), while for the implants placed at 5 mm, 10 mm, and 15 mm, the indicated stresses were less than 2.46 MPa following an increasing trend with an increase in the distance. The stresses in the implants were maximum when placed at 15-15-degree angulations (0.93 under unilateral and 0.92 MPa under bilateral loading). For lower angulations, the stresses on the implants ranged from 0.05 to 0.87 MPa. No specific trend was observed in stresses and strains with 0-5-, 0-10-, and 0-15-degree angulations, but an increasing trend was observed with 5-5-, 10-10-, and 15-15-degree angulations under unilateral loading. Under bilateral loading, the stresses and strains on the implants and the mandible showed negligible variations across all 6 angulations.
CONCLUSIONS: The most posterior position of implants (20 mm) exhibited the highest stresses and strains on the implants and the mandible under both loading conditions. Implants placed with 15-15-degree angulations exhibited the highest stresses. Stresses and strains were similar in implants with lower angulations.
PURPOSE: The purpose of this in vitro study was to evaluate the crestal strain around 2 implants to support mandibular overdentures when placed at different positions.
MATERIAL AND METHODS: Edentulous mandibles were 3-dimensionally (3D) designed separately with 2 holes for implant placement at similar distances of 5, 10, 15, and 20 mm from the midline, resulting in 4 study conditions. The complete denture models were 3D designed and printed from digital imaging and communications in medicine (DICOM) images after scanning the patient's denture. Two 4.3×12-mm dummy implants were placed in the preplanned holes. Two linear strain gauges were attached on the crest of the mesial and distal side of each implant (CH1, CH2, CH3, and CH4) and connected to a computer to record the electrical signals. Male LOCATOR attachments were attached, the mucosal layer simulated, and the denture picked up with pink female nylon caps. A unilateral and bilateral force of 100 N was maintained for 10 seconds for each model in a universal testing machine while recording the maximum strains in the DCS-100A KYOWA computer software program. Data were analyzed by using 1-way analysis of variance, the Tukey post hoc test, and the paired t test (α=.05).
RESULTS: Under bilateral loading, the strain values indicated a trend with increasing distance between the implants with both right and left distal strain gauges (CH4 and CH1). The negative (-ve) values indicated the compressive force, and the positive (+ve) values indicated the tensile force being applied on the strain gauges. The strain values for CH4 ranged between -166.08 for the 5-mm and -251.58 for the 20-mm position; and for CH1 between -168.08 for the 5-mm and -297.83 for the 20-mm position. The remaining 2 mesial strain gauges for all 4 implant positions remained lower than for CH4 and CH1. Under unilateral-right loading, only the right-side distal strain gauge CH4 indicated the increasing trend in the strain values with -147.5 for the 5-mm, -157.17 for the 10-mm, -209.33 for the 15-mm, and -234.75 for the 20 mm position. The remaining 3 strain gauges CH3, CH2, and CH1 ranged between -28.33 and -107.17. For each position for both implants, significantly higher (P
PURPOSE: The purpose of this 3D finite element analysis study was to evaluate the biomechanical behavior of 2-implant mandibular overdentures (2IMO) and their individual components by using implants of different diameters.
MATERIAL AND METHODS: A 3D mandibular model was obtained from the cone beam computed tomography (CBCT) images of a 59-year-old edentulous man, and a 3D denture model was developed from intraoral scanning files in the Mimics software program. A 3D model of different diameters of implants (2.5 mm, 3.0 mm, 3.5 mm, and 4.0 mm) with a LOCATOR attachment was developed in the Solidworks software program. Two same-sized implants were inserted in the mandibular model at 10 mm from the midline in the 3Matics software program. A vertical load of 100 N was applied on the first molar region on the right side or both sides in the ANSYS software program. The maximum von Mises stresses and strains were recorded and analyzed.
RESULTS: Stresses within the implants decreased with an increase in diameter (from 2.5 mm to 3 mm, 3.5 mm, and 4.0 mm) of the implants. The highest stresses were observed with 2.5-mm-diameter implants (0.949 MPa under unilateral and 0.915 MPa under bilateral loading) and the lowest with Ø4-mm implants (0.710 MPa under unilateral and 0.703 MPa under bilateral loading). The strains on the implants ranged between 0.0000056 and 0.0000097, and those on the mandible ranged between 0.0000513 and 0.0000566 across all diameters of the implants without following a specific trend.
CONCLUSIONS: In 2IMO, the stresses in the implants and mandible decreased with an increase in the diameter of the implants. The implants of lesser diameter (2.5 mm) exhibited the highest stresses and strains, and the implants of the largest diameter (4 mm) exhibited the lowest stresses and strains under unilateral and bilateral loading conditions.
MATERIALS AND METHODS: Dental academics in Malaysian dental schools were invited to complete a questionnaire by email and post. The survey comprised questions on research activities in the past 12 months, socio-demographic and professional characteristics, and the R&D Culture Index. Principal components factor analysis was carried out to confirm the factor structure of the R&D Culture Index. Chi-square test was used to identify association of research activities with R&D culture, and socio-demographic and professional characteristics. Binary logistic regression was carried to identify predicators of research activities.
RESULTS: Of 256 potential participants contacted, 128 (50%) useable responses were returned. Three R&D Culture factors accounting for 57.4% of variance were extracted. More positive perception of R&D Support was associated with Malaysians (0.025) and those employed in Government schools (0.017). R&D Skills and Aptitude were associated with older respondents (0.050), PhD qualification (0.014) and more years in academia (0.014). R&D Intention was associated with any of the socio-demographic characteristics. Thirty (23.4%) respondents reported a peer-review research publication in the past 12 months, which was associated with having a PhD (OR 12.79, CI 1.28-127.96), after adjustment in regression analyses.
DISCUSSION: Postgraduate research training should be encouraged to promote participation in research activities. R&D culture did not appear to impact on research productivity. Other factors such as individual attitudinal interests should be studied.
HIGHLIGHT: There were conflicting results regarding sexual dimorphism and population characterization of the palatal rugae patterns. All rugae showed positional changes, increased lengths, and lower numbers, but no significant shape changes with growth. The lengths, numbers, and positions of the rugae were affected by orthodontic treatment, especially their lateral points, but their individual characteristics did not change.
CONCLUSION: The diversity in rugae patterns and their potential for sex discrimination among different populations showed differing results due to individual variations and the complex influence of genetic, growth, and environmental factors on their morphology.
OBJECTIVE: The objective of this study is to evaluate the cost-effectiveness of dental home visits and oral health information, in the form of educational leaflets, in preventing new caries development in young children, compared to those receiving only educational leaflets over a period of two years. Cost-effectiveness analysis will be used to evaluate the cost-effectiveness of dental home visits.
METHODS: This is a collaborative project with the Oral Health Division of the Ministry of Health Malaysia. The Oral Health Division will provide access to a subsample from the National Oral Health of Preschoolers Survey which was carried out in 2015. The population of interest is children aged 5 and 6 years from kindergartens in the Selangor state of Malaysia. The study adopted a societal perspective for cost-effectiveness analysis and all types of resources that are of value to society will be included in analyzing the costs; such as cost to the patient, cost to the provider or institution, and indirect costs because of loss of productivity.
RESULTS: The trial has been approved by the International Medical University Malaysia's Joint Research and Ethics Committee (Project ID: IMU R157-2014 [File III - 2016]). This trial is currently recruiting participants.
CONCLUSIONS: The number of young children in Malaysia who have been referred to the hospital children's dentistry service for severe caries is disturbing. The cost of dental treatment in young children is high due to the severity of the caries which require an aggressive treatment, and the need for general anesthesia or sedation. This study will provide information on the cost and effectiveness of DHVs in caries prevention of young children in Malaysia.
REGISTERED REPORT IDENTIFIER: RR1-10.2196/10053.
Methods: A 33-item EI questionnaire was completed by 46 dental undergraduates in a cross-sectional study. Responses, measured on a five-point Likert scale, were summed to yield EI scores. Patients treated by the same undergraduates were invited to complete a patient satisfaction (PS) questionnaire. EI and PS scores were calculated and compared by undergraduates' gender and the patients' age and education status. The four EI factors (optimism/mood regulation, appraisal of emotions, utilization of emotions, and social skills of students) were correlated with PS using Spearman's correlation test with a significance level set at p < 0.05.
Results: EI scores did not differ significantly between male (N = 23) and female (N = 23) undergraduates (p=0.218). PS was not associated with patients' gender, but those educated to the secondary school level were more likely to be satisfied compared to those educated to the college/university level (p=0.022). Of the four EI factors, optimism/mood regulation was positively correlated with PS (p=0.049).
Conclusion: The results of the study suggest that the EI of the students can influence PS. Practical Implications. Interventions to enhance EI can be developed to improve the patient experience.
METHODOLOGY: This study was approved by the institutional Joint Research and Ethics Committee, International Medical University, Malaysia (number 373/2016); consisted of 180 eligible pre-school children from a private school. Study tools included demographic, clinical oral health data form, the Early Childhood Oral Health Impact Scale (ECOHIS) and family functioning-12-item general functioning subscale. Written consent was sought prior to data collection. Data were analysed by SPSS v.22.0; descriptive statistics for socio-demographic details, clinical information, HRQoL and FAD scores. The parametric tests included independent sample t test and ANOVA to evaluate the associations between the dependent variable. Binary logistic regression models were applied to assess the impacts on OHRQoL (P value
MATERIALS AND METHODS: An audit checklist with 13 criteria for good documentation was adapted from guidelines proposed by the American Association of Orthodontists and British Orthodontic Society. Orthodontic chart documentation in 103 removable appliance therapy patients under 4th and 5th year dental undergraduates' care was retrieved from the electronic record of the University dental clinic and audited. The audit exercise explored in detail the thirteen criteria for good documentation and eight assessment attributes of the first criterion, namely, basic orthodontic examination. The level of compliance was measured as the percentage records meeting the criteria. The data were statistically analysed using SPSS 26.0 (SPSS, Inc., Chicago, IL, USA).
RESULTS: There was no complete compliance for any of the criteria. Thirty-five (33.9%) patient charts reported basic orthodontic examination documentation adequately. Compliance was the highest for documentation of treatment modality (77.6%), appliance delivery encounters (77.6%), and appliance adjustment appointments (83.5%). About 51.4% of the 68 patient charts (treatment of 35 patients of the total 103 were in the progress stage) stated adequately the outcome of treatment. Only 22% of the 68 patient charts had the details for retention protocol. There was statistically significant difference in chart documentation between male and female students for basic orthodontic assessment and appliance delivery and patient instructions attributes.
CONCLUSION: The clinical audit demonstrated poor compliance with the criteria for orthodontic chart documentation. The audit should be repeated after the provision of learning opportunities and self-critical analysis.
METHODS: Clinical audit learning was introduced in Year 3 of a 5-year curriculum for dental undergraduates. During classroom activities, students were briefed on clinical audit, selected their audit topics in groups of 5 or 6 students, and prepared and presented their audit protocols. One chosen topic was RCT, in which 3 different cohorts of Year 3 students conducted retrospective audits of patients' records in 2012, 2014 and 2015 for their compliance with recommended record keeping criteria and their performance in RCT. Students were trained by and calibrated against an endodontist (κ ≥ 0.8). After each audit, the findings were reported in class, and recommendations were made for improvement in performance of RCT and record keeping. Students' compliance with published guidelines was presented and their RCT performances in each year were compared using the chi-square test.
RESULTS: Overall compliance with of record keeping guidelines was 44.1% in 2012, 79.6% in 2014 and 94.6% in 2015 (P = .001). In the 2012 audit, acceptable extension, condensation and the absence of mishap were observed in 72.4, 75.7% and 91.5%; in the 2014 audit, 95.1%, 64.8% and 51.4%; and in 2015 audit, 96.4%, 82.1% and 92.8% of cases, respectively. In 2015, 76.8% of root canal fillings met all 3 technical quality criteria when compared to 48.6% in 2014 and 44.7% in 2012 (P = .001).
CONCLUSION: Clinical audit-feedback cycle is an effective educational tool for improving dental undergraduates' compliance with record keeping and performance in the technical quality of RCT.
METHODS: A draft set of EPA statements was developed based on the consensus of an expert panel. These were then mapped to the nationally determined minimum experience thresholds (clinical and procedural experiences/competencies) and aligned to task-based instructional strategy. The EPAs were validated to improve the relevance by using a criterion-based rubric.
RESULTS: An end-to-end process workflow led to the development of an EPA-based educational framework to bridge the gaps in the curriculum. The process identified a total of 41 EPAs and out of which, 10 EPAs were notated as core EPAs and will be subjected to structured workplace-based assessment complying to the national standards. The validation exercise rated core EPAs with an overall score matching close to the cut-off of 4.07 (Equal rubric).
CONCLUSION: The end-to-end process workflow provided the opportunity to elaborate a structured process for the development of EPAs for undergraduate dental education. As validation is a continuous process, feedback from implementation will inform the next steps.
METHODS: 5- to 6-year-olds attending kindergartens were randomized to receive either 6-month dental home visits and education leaflets (Intervention group) or education leaflets alone (Control group) over 24 months. To detect a 15% difference in caries incidence with a significance level of 5% and power of 80%, 88 children were calculated to be needed in the Intervention group and 88 in the Control. Baseline clinical data included oral examinations at the kindergartens. Follow-up visits were made on the 6th, 12th and 18th month. At the end of the 24 months, both the Intervention and Control groups were visited for oral examinations. The primary outcome was caries incidence, measured by the number and proportion of children who developed new caries in the primary molars after 24 months. The secondary outcome was the number of primary molars that developed new caries (d-pms). Frequency distributions of participants by baseline socio-demographic characteristics and caries experience were calculated. The chi-square test was used to test differences between the caries experience in the Intervention and Control groups. The t test was used to compare the mean number of primary molars developing new caries between the Intervention Group and the Control Group. The number of children needed to treat (NNT) was also calculated.
RESULTS: At the 24-month follow-up, 19 (14.4%) developed new caries in the Intervention Group, compared to 60 (60.0%) in the Control Group (p = .001). On average, 0.2 (95% CI = 0.1-0.3) tooth per child in the Intervention Group was observed to have developed new caries compared to 1.1 (95% CI = 0.8-1.3) tooth per child in the Control Group (p = .001). The number of children needed to treat (NNT) to prevent one child from developing new caries was 2.2.
CONCLUSIONS: The present study has demonstrated that 6-month home visits to families of 5- to 6-year-olds are effective in caries prevention in 5- to 6-year-olds of low-income families in a middle-income country where access to health services, including oral health promotion services, is limited.