Long-term observation of periodontal condition following placement of removable partial dentures with rigid retainers and major connector in patients with/without diabetes: A retrospective study

Longevity of acrylic and cobalt-chromium removable partial dentures-A ten-year retrospective survival analysis of 1246 denture-wearing patients

OBJECTIVES

to assess the survival rates of removable partial dentures (RPDs) and identify factors impacting their longevity.

METHODS

electronic health records were retrieved of patients aged ≥18 who received RPDs between 2010 - 2021 with a follow-up of ≥ three months. Data extracted included demographics, medical history, dental charting, periodontal screening and recording scores, prostheses details and related interventions, including new dentures/denture remakes, and maintenance. Multivariate Mixed-Effect Cox regression was performed to identify potential RPD survival risk factors. Reduced model selection was reached using a backward step-down by comparing the performance of these multivariable models using the ANOVA test.

RESULTS

1893 RPDs from 1246 patients were included, with a median follow-up of 21.8 months (range from 3 to 131.3 months). Three hundred and twelve patients received a maxillary RPD, 460 received a mandibular RPD, and the remaining 474 patients received both maxillary and mandibular RPDs. Metal-based RPDs had a median survival of 73 months (95%CI: 70 - 82) versus 45 months (95% CI: 37-67) for acrylic ones. Multivariable mixed effects Cox model showed that the lifespans of RPDs were longer amongst patients receiving more maintenance care within three months [Hazards Ratio (HR)=0.89 (0.83, 0.96)] and after three months [HR=0.53 (0.46, 0.61)] of denture delivery, patients wearing both maxillary and mandibular RPDs [HR=0.67 (0.52, 0.87)], and patients receiving metal-based RPDs [HR=0.31 (0.23, 0.42)].

CONCLUSIONS

Metal-based dentures, dual arch restoration, and increased maintenance positively impact the survival of RPDs.

CLINICAL SIGNIFICANCE

Adapting consent and warranty practices is advised to reflect RPD performance variations.

Effect of mandibular bilateral distal extension denture design on masticatory performance

PURPOSE

Removable partial dentures have a wide range of applications as missing tooth prostheses, and the denture design can be quite diverse. However, the factors affecting masticatory function remain unclear. We investigated the effect of denture design, especially the use of indirect retainers and major connectors, on masticatory function in patients with mandibular bilateral distal extension dentures.

METHODS

Fifty-three patients with mandibular Kennedy Class I and Eichner classification B occlusal support were included in this study. Masticatory performance (MP) was assessed using gummy jelly. For the dentures, the type of major connector (bar or apron), presence or absence of indirect retainers, number of rests, and number of artificial teeth were evaluated. The number of functional teeth and occlusal support, Eichner classification, maxillary denture usage, mandibular residual ridge height, and duration of denture use were also evaluated. The factors influencing on the MP were evaluated using the Mann-Whitney U test, Spearman's correlation coefficient, and logistic regression analysis.

RESULTS

MP was significantly higher when the major connector was bar-type or when there was an indirect retainer than with an apron-type or no indirect retainer. MP was positively correlated with the number of functional teeth, occlusal support, and number of rests. Logistic regression analysis revealed that the number of functional teeth and the presence or absence of an indirect retainer were factors that significantly influenced the MP.

CONCLUSIONS

An indirect retainer setting is useful for achieving good masticatory performance in mandibular bilateral distal extension dentures.

Radiographic predictive factors for 10-year survival of removable partial denture abutment teeth: Alveolar bone level and density

PURPOSE

To determine postoperative periodontal and radiographic factors that predict the survival rates of abutments of removable partial dentures (RPDs).

METHODS

Patients who wore RPDs for > 10 years and received supportive periodontal therapy were included. Periodontal examinations and radiographic assessments were conducted on 83 abutment teeth in 35 patients at baseline, and five years after RPD insertion. In addition to conventional factors, such as tooth mobility at 5 years, radiographic factors, such as the crown-root ratio (ΔCR ratio) and gray-level changes reflecting changes in alveolar bone density (ΔABD), were evaluated. The impact of the covariables on the 10-year survival of abutment teeth was estimated using a multivariate Cox regression model, considering multicollinearity.

RESULTS

Patients were classified as having A2-B2 (45.7%) and B3-C2 (54.3%) tooth loss, according to the Eichner classification. A probing depth ≥ 4 mm, tooth mobility ≥ grade 1, and CR ratio ≥ 1 were found in 30.1%, 33.7%, and 51.8% of abutment teeth, respectively. The 10-year survival rate of abutment teeth was 86.7%. Multivariate analysis showed that the 10-year survival of abutment teeth was significantly associated with root canal treatment (P = 0.045, hazard ratio [HR] = 1.23), the 5-year ΔCR ratio (P = 0.022, HR = 3.20), and ΔABD on the edentulous side of the abutment teeth (P = 0.047, HR = 1.08).

CONCLUSIONS

In addition to root canal treatment, changes in the CR ratio and radiographic alveolar bone density at five years predicted the long-term survival rate of RPD abutments.