Evaluation of Crowns and Conventional Fixed Partial Dentures Provided to Patients at the School of Dental Sciences, University of Nairobi.

Abstract

Background: Fixed partial dentures (FPDs) have a high survival rate, however they are often associated with biological and technical complications. Patients treated with crowns and FPDs at the School of Dental Sciences (SDS) are usually not followed up due to lack of a proper recall system. Consequently, there are no available data on the outcomes of crowns and FPDs that have been provided to patients at the School of Dental Sciences. Objective: To evaluate crowns and conventional fixed partial dentures provided to patients between the years 2009 and 2015 at the School of Dental Sciences, University of Nairobi. Study design: This was a descriptive cross sectional study. The study sample comprised of patients who had received crowns and fixed partial dentures at the School of Dental Sciences between the year 2009 and 2015. Materials and methods: A close ended interviewer-administered questionnaire was used to collect information on socio-demographic data, oral hygiene practices, pain/sensitivity associated with prosthesis, level of satisfaction with the prosthesis, frequency of dental visits and presence of systemic illnesses. Clinical examination was conducted to evaluate the quality of crowns and FPDs using the California Dental Association (CDA) criteria where prostheses were classified as ‘excellent’, ‘acceptable’, ‘to be corrected’ or ‘to be replaced’. The periodontal health of crowned and abutment teeth was evaluated by measurement of gingival scores, periodontal attachment loss, periodontal probing depth and mobility. The crowned teeth and FPD abutments were radiographically evaluated for presence of dental caries, periapical radiolucency, widening of the periodontal ligament space, root filling, intracanal posts and bone loss. Data analysis and presentation: The data collected was analyzed using the Statistical Package for Social Sciences (SPSS v. 21, IBM). The information obtained was organized and

presented as descriptive statistics in form of tables and figures. Pearson’s Chi square and Fisher’s exact test were applied to test the relationship between various variables. Results: Ninety seven patients were included in the study. Their ages ranged between 23 to 76 years, with a mean of 44.65 ( ± 12.61 SD) years. Thirty five (36.1%) of these were male and 62 (63.9%) were female. The patients evaluated had been provided with a total of 69 FPDs and 81 crowns. The mean length of service for the FPDs was 42.79 (± 22.25 SD) months while it was 35.94(± 20.05 SD) months for the crowns. Sensitivity to thermal stimuli, porcelain fractures and defective margins were the most common complications associated with FPDs. The success rate for FPDs was 75.3%. There was a statistically significant association between FPD design and success (Fisher’s Exact Test = 8.194, p=0.018). Cantilever design demonstrated the lowest success rate. There was also a significant association between the position of the fixed partial denture in the mouth and success (χ2= 6.596, p = 0.017). Success rate was higher among FPDs located in the posterior region. Decementation, sensitivity to thermal stimuli and defective margins were the most common complications associated with crowns. The success rate of crowns was 66.7%. There was statistically significant association between the level of training of the clinician and the success of crowns (χ2 = 7.772, p= 0.009). Crowns fabricated by graduate students had a higher success rate compared to those by undergraduate students and dental interns. There was also a statistically significant association between length of service and the success of crowns (Fisher’s exact test = 8.846, p=0.011).The crowns which had served for a longer period exhibited a lower success rate. Conclusion: The success rate for FPDs determined as 75.4% (95% CI: 54.88-95.85%) and that for crowns determined as 66.7%(95% CI: 48.89-84.45%) was lower than the success rate reported in other studies. The position and design of FPDs had a significant influence on the

success rate whereas the level of training of the clinician and length of service had a significant influence on the success rate of the crowns. Porcelain fractures, defective margins and loss of retention were the most common complications associated with both crowns and fixed partial dentures, additionally sensitivity was common among fixed partial dentures.