Treatment of edentulous mandible with metal-resin fixed complete dentures: A 15- to 20-year retrospective study.

OBJECTIVES: The purpose of this retrospective study was to report the implant and prosthetic complications of mandibular metal-resin fixed complete dentures (MRFCDs) opposing a maxillary complete removable dental prosthesis (CRDP) in a 15- to 20-year post-placement follow-up period. MATERIAL AND METHODS: Dental records of 24 edentulous patients treated by a mandibular MRFCD and a maxillary CRDP were reviewed. Complications for the implants, MRFCDs, and CRDPs were recorded in four different recall periods: 0-5 years, 5-10 years, 10-15 years, and more than 15 years. The survival and failure times based on Kaplan-Meier statistics were analyzed using Lifetest procedures. Product-limit survival estimates were used for cumulative survival rates (CSRs). RESULTS: The mean service time was 18.5 years. The CSR for the implants and MRFCDs was 91.8% at 16.9 years (confidence intervals: 85.2% and 95.5%) and 80% at 19.6 years (confidence intervals: 44.1% and 94.1%), respectively. The implant failures after 15 years occurred because of a tumor resection. Acrylic resin tooth fracture (45.8% of patients) and wear (75% of patients) were the most common complications with the MRFCD. Retaining screw complications [loosening (8.1% of retaining screws) and fracture (11.3% of retaining screws)] were also common. CONCLUSIONS: The outcomes seen with MRFCD over the long term were favorable. After placement of prostheses, 1 implant loss was observed potentially due to prosthetic/hygiene/periodontal factors. However, potential maintenance complications such as acrylic resin tooth fracture and/or wear and retaining screw loosening and fracture may occur in the long term when a similar design is used for the mandible.

Anteroposterior Spread and Cantilever Length in Mandibular Metal-Resin Implant-Fixed Complete Dental Prostheses: A 7- to 9-Year Analysis.

PURPOSE: The purpose of this retrospective study was to investigate the relationship of specific prosthetic complications in patients with a maxillary complete removable dental prosthesis (CRDP) opposing a mandibular metal-resin implant-fixed complete dental prosthesis (MRIFCDP) with respect to anteroposterior (AP) spread and cantilever length. MATERIALS AND METHODS: Of the 46 patients contacted for this study, 23 patients responded. All patients had been treated with a maxillary CRDP and a mandibular MRIFCDP. They were reviewed for prosthetic complications, and the AP spread and cantilever length were evaluated. A polyvinyl siloxane impression was made of each MRIFCDP so that cantilever length and AP spread could be measured. The average recall time was 8.5 years. The mechanical complications noted were screw-related complications, including both the prosthetic and the abutment screw, consisting of loosening and/or fracture, and fracture of the metal framework. Three different individuals repeated each measurement three times. Inter- and intrarater reliability was evaluated with the intraclass correlation coefficient, and a linear regression analysis of age and average cantilever length to AP spread ratio was calculated. In addition, calculations using this ratio were divided into two groups (> 2.1 and ≤ 2.1) and examined with each variable individually. A logistic regression analysis was performed for a comparison between the two AP spread ratio groups by age, right cantilever length, left cantilever length, average cantilever length, posterior spread, and failures. RESULTS: None of the predictor values was significant for the linear regression analysis of age, cantilever length, and AP ratio on number of failures. There was no significance in complications between the groups that had an AP spread ratio > 2.1 and groups that had an AP spread ratio ≤ 2.1. CONCLUSIONS: There was no statistical significance in predicting whether a screw-related complication would occur in relation to age, cantilever length, or AP spread ratio. There was no increase or decrease in complications whether the AP spread ratio was greater than or less than or equal to 2.1. In mandibular MRIFCDPs opposing maxillary complete denture situations, screw-related complications may be less likely regardless of the patient's age, cantilever length, or AP spread ratio of the prosthesis.

Prosthetic complications in mandibular metal-resin implant-fixed complete dental prostheses: a 5- to 9-year analysis.

PURPOSE: The purpose of this study was to investigate the prosthetic complications of patients with a maxillary complete removable dental prosthesis opposing a mandibular metal-resin implant fixed complete dental prosthesis. MATERIALS AND METHODS: This study is a retrospective analysis of an ongoing prospective study. Dental records from 46 patients treated with a maxillary complete removable dental prosthesis and a mandibular metal-resin implant-fixed complete dental prosthesis were reviewed for 15 different prosthetic complications. The average recall time was 7.9 years. The percentage of patients exhibiting each complication and corresponding 95% confidence intervals was calculated. Logistic regression analysis determined the effect of recall period, age, and gender on each of the following major complications: tooth fracture, complete denture relines, screw complications, and tooth replacement. The recall period was divided into 3 parts: < or = 2 years, 2 to 5 years, and more than 5 years. RESULTS AND CONCLUSION: Statistical significance was exhibited for complete denture relines, posterior tooth replacement, and screw complications. No abutment or framework fractures were recorded for any of the time intervals. The most common complications were prosthetic tooth fracture, tooth wear, maxillary hard relines, and screw complications. Patients were 1.06 times more likely to require a heat-processed hard reline with each year increase of age. After 2 to 5 years and > 5 years, patients were 3.7 times and 8.5 times more likely to require a hard reline than at < or = 2 years. Patients were 52.5 times more likely to need posterior tooth replacement at > 5 years than at < or = 2 years, and 7.7 times more likely to encounter a screw complication at > 5 years than at < or = 2 years.