Ergonomic interventions for preventing musculoskeletal disorders in dental care practitioners.

BACKGROUND: Dentistry is a profession with a high prevalence of work-related musculoskeletal disorders (WMSD) among practitioners, with symptoms often starting as early in the career as the student phase. Ergonomic interventions in physical, cognitive, and organisational domains have been suggested to prevent their occurrence, but evidence of their effects remains unclear. OBJECTIVES: To assess the effect of ergonomic interventions for the prevention of work-related musculoskeletal disorders among dental care practitioners. SEARCH METHODS: We searched CENTRAL, MEDLINE PubMed, Embase, PsycINFO ProQuest, NIOSHTIC, NIOSHTIC-2, HSELINE, CISDOC (OSH-UPDATE), ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform (ICTRP) Search Portal to August 2018, without language or date restrictions. SELECTION CRITERIA: We included randomised controlled trials (RCTs), quasi-RCTs, and cluster RCTs, in which participants were adults, aged 18 and older, who were engaged in the practice of dentistry. At least 75% of them had to be free from musculoskeletal pain at baseline. We only included studies that measured at least one of our primary outcomes; i.e. physician diagnosed WMSD, self-reported pain, or work functioning. DATA COLLECTION AND ANALYSIS: Three authors independently screened and selected 20 potentially eligible references from 946 relevant references identified from the search results. Based on the full-text screening, we included two studies, excluded 16 studies, and two are awaiting classification. Four review authors independently extracted data, and two authors assessed the risk of bias. We calculated the mean difference (MD) with 95% confidence intervals (CI) for continuous outcomes and risk ratios (RR) with 95% confidence intervals for dichotomous outcomes. We assessed the quality of the evidence for each outcome using the GRADE approach. MAIN RESULTS: We included two RCTs (212 participants), one of which was a cluster-randomised trial. Adjusting for the design effect from clustering, reduced the total sample size to 210. Both studies were carried out in dental clinics and assessed ergonomic interventions in the physical domain, one by evaluating a multi-faceted ergonomic intervention, which consisted of imparting knowledge and training about ergonomics, work station modification, training and surveying ergonomics at the work station, and a regular exercise program; the other by studying the effectiveness of two different types of instrument used for scaling in preventing WMSDs. We were unable to combine the results from the two studies because of the diversity of interventions and outcomes.Physical ergonomic interventions. Based on one study, there is very low-quality evidence that a multi-faceted intervention has no clear effect on dentists' risk of WMSD in the thighs (RR 0.57, 95% CI 0.23 to 1.42; 102 participants), or feet (RR 0.64, 95% CI 0.29 to 1.41; 102 participants) when compared to no intervention over a six-month period. Based on one study, there is low-quality evidence of no clear difference in elbow pain (MD -0.14, 95% CI -0.39 to 0.11; 110 participants), or shoulder pain (MD -0.32, 95% CI -0.75 to 0.11; 110 participants) in participants who used light weight curettes with wider handles or heavier curettes with narrow handles for scaling over a 16-week period.Cognitive ergonomic interventions. We found no studies evaluating the effectiveness of cognitive ergonomic interventions.Organisational ergonomic interventions. We found no studies evaluating the effectiveness of organisational ergonomic interventions. AUTHORS' CONCLUSIONS: There is very low-quality evidence from one study showing that a multi-faceted intervention has no clear effect on dentists' risk of WMSD in the thighs or feet when compared to no intervention over a six-month period. This was a poorly conducted study with several shortcomings and errors in statistical analysis of data. There is low-quality evidence from one study showing no clear difference in elbow pain or shoulder pain in participants using light weight, wider handled curettes or heavier and narrow handled curettes for scaling over a 16-week period.We did not find any studies evaluating the effectiveness of cognitive ergonomic interventions or organisational ergonomic interventions.Our ability to draw definitive conclusions is restricted by the paucity of suitable studies available to us, and the high risk of bias of the studies that are available. This review highlights the need for well-designed, conducted, and reported RCTs, with long-term follow-up that assess prevention strategies for WMSDs among dental care practitioners.

Age estimation using development of third molars in South Indian population: A radiological study.

AIM: To assess the estimation of chronological age based on the stages of third molar development following the eight stages (A-H) method of Demirjian et al. in Chennai population of South India. MATERIALS AND METHODS: A sample consisting of 848 individuals (471 males and 377 females) aged between 14 and 30 years was randomly selected for the clinical evaluation and 323 orthopantomograms with clinically missing third molars were taken for radiological evaluation using Demirjian's method from a Chennai population of known chronological age and sex. Statistical analysis was performed using Pearson's Chi-square test and mean values were compared between the study groups using t-test or analysis of variance (ANOVA) followed by Tukey's highly significant difference (HSD). In the present study, P < 0.05 was considered as the level of significance. RESULTS: The results showed that the mean age of having clinically completely erupted maxillary third molars was 22.41 years in male subjects and 23.81 years in female subjects and that of mandibular third molars was 21.49 years in male subjects and 23.34 years in female subjects. Mandibular third molars were clinically missing more often in females than in males. Eruption of mandibular third molars was generally ahead of the emergence of maxillary third molars into the oral cavity. Third molar development between male and female subjects showed statistically significant differences at calcification stage F and stage G in maxillary third molars and stage F in mandibular third molars (P < 0.05). CONCLUSION: There are differences indicating that maxillary and mandibular third molar eruption reached Demirjian's formation stages earlier in males than in females. It is suggested that in future studies, to increase the accuracy of age determination, indications of sexual maturity and ossification should also be evaluated in addition to third molar mineralization.

The impact of chimerism in DNA-based forensic sex determination analysis.

Sex determination is the most important step in personal identification in forensic investigations. DNA-based sex determination analysis is comparatively more reliable than the other conventional methods of sex determination analysis. Advanced technology like real-time polymerase chain reaction (PCR) offers accurate and reproducible results and is at the level of legal acceptance. But still there are situations like chimerism where an individual possess both male and female specific factors together in their body. Sex determination analysis in such cases can give erroneous results. This paper discusses the phenomenon of chimerism and its impact on sex determination analysis in forensic investigations.