Narrow-Diameter Implants for Partial Fixed and Removable Prostheses: A Systematic Review and Meta-Analysis.

PURPOSE: To answer the following focus question: Are narrow-diameter implants feasible to support fixed dental prostheses (FDPs) and partial removable dental prostheses (PRDPs)? MATERIALS AND METHODS: This review followed the PRISMA statement and was registered in the PROSPERO database (CRD42020153729). Six databases and the gray literature were searched through October 2021 without language, publication time, or follow-up restrictions. The main outcomes were survival, success, and marginal bone loss (MBL). Risk of bias was assessed for each study design, and random-effects meta-analyses were performed (α = .05). RESULTS: Seventeen studies were included in the qualitative analysis, and 3 were included in the meta-analyses. In total, 1,624 NDIs and 339 standard-diameter implants (SDIs) were placed in 1,060 patients. Follow-up varied from 1 to 10 years, and 17 failures (implant loss) were recorded. No differences in survival rate for FDPs supported by NDIs vs SDIs were found (odds ratio [OR] = 0.59, 95% CI: 0.18 to 1.92, P = .38). However, Kaplan-Meier analysis evaluating only NDI performance revealed a higher survival rate of NDIs ≥ 3.3-mm diameter (P = .002), placed with delayed loading (P = .024), and placed in the maxilla (P = .014). FDPs supported by NDIs vs SDIs presented similar success rates (OR = 1.48, 95% CI: 0.41 to 5.34, P = .55); however, MBL was lower in the NDI group (mean difference = -0.23 mm, 95% CI: -0.41 to -0.06, P = .01). Insufficient data regarding PRDPs were available. CONCLUSION: Despite the limited studies available, FDPs supported by NDIs presented survival and success rates comparable to those supported by SDIs, with slightly lower MBL. For PRDPs, strong conclusions were not possible.

Activation and installation of orthodontic appliances temporarily impairs mastication.

OBJECTIVES: To investigate the masticatory (masticatory performance, bite force, swallowing threshold, muscle activity, and questionnaires) and nutritional (nutrient intake) impacts of the activation and/or installation of different orthodontic appliances (fixed labial, lingual appliances, and clear aligners). MATERIALS AND METHODS: Six electronic databases and gray literature were searched (up to May 2021) for relevant studies evaluating mastication and nutrition after activation/installation of orthodontic appliances. This review followed PRISMA guidelines and was registered at PROSPERO (CRD42020199510). The risk of bias (RoB 2 and ROBINS-I) and evidence quality Grading of Recommendations Assessment, Development, and Evaluation were analyzed. RESULTS: Of 4226 recorded and screened, 15 studies were finally included. Masticatory performance (standardized mean difference [SMD]: 1.069; 95% coefficient interval [CI]: 0.619 to 1.518) and bite force (SMD: -2.542; 95% CI: -4.867 to -0.217) reduced in the first 24 to 48 hours of fixed labial appliance installation/activation, but they were both normalized after 30 days (P > .05). The swallowing threshold remained constant (P > .05). Nutritional intake was rarely reported but showed copper (P = .002) and manganese (P = .016) reductions, with higher calorie and fat intake (P < .05). Lingual appliances impacted chewing more than labial, and clear aligner wearers reported fewer chewing problems (P < .001). Low to very low levels of evidence were found. CONCLUSIONS: Based on low to very low levels of evidence, mastication was reduced during the first 24 to 48 hours of fixed labial appliance activation/installation, but it was transitory (up to 30 days). Due to insufficient data, the nutritional impact of orthodontic appliances was not conclusive.