Prevalence of Overhanging Amalgam Margins in a Dental School Setting

Objectives: Since amalgam restorations are placed by dental students as part of clinical training, they have to be proficient in this particular treatment before graduation. Some amalgam restorations, if not properly finished, are liable to exhibit overhanging amalgam margins as they are performed by novice dental students. Teeth containing these overhanging amalgam margins are susceptible to recurrent caries and periodontal disease. The objectives of this study is to examine intra-oral bite-wing radiographs to locate overhanging amalgam margins placed by dental students, presence or absence of periodontal disease in the region immediately subjacent to the overhanging margins and recurrent caries under restorations containing amalgam margins.
Methods: Electronic charts of three hundred patients who reported to the student clinics with moderate and high-risk caries between 2007 and 2014 will be studied. Intra-oral Bite-wing Radiographs from the Imaging software of the electronic charts of these patients will be evaluated. After information on overhanging margins is obtained after initial placement, subsequent radiographs taken during periodic oral examinations will be evaluated for associated recurrent caries and periodontal disease.
Data will be recorded from evaluation of initial amalgam restorations on bite-wing radiographs on recurrent caries and periodontal disease. Descriptive statistics will be used to analyze and describe the data, which includes but not limited to, prevalence, odds ratio, chi-squared test and Fisher test. Logistic regression will also be used.
Results: A total of 323 patient charts were reviewed. 59 were found with one or more amalgam restorations with overhangs. This indicates approximately 18.3% of patients had overhangs. 27 out of 59 patients had localized bone loss near where the amalgam overhang was placed. 659 teeth had a mesial, distal or mesiodistal lesion that was treated by students with amalgam and, among them, 68 teeth were restored with an overhang (10.3%). 13 teeth were re-treated to remove the overhang or to treat existing recurrent caries. Further elaborate statistical analysis will be performed.
Conclusions: Quality assurance techniques can be implemented at dental institutions to mitigate the effects of overhanging amalgam margins on restorations placed by dental students.