Effect of Drilling Preparation on Immediately Loaded Implants: An In Vivo Study in Sheep.

PURPOSE: To determine the biologic and biomechanical effects of two implant drilling protocols on the cortical bone around implants subjected to immediate loading. MATERIALS AND METHODS: A total of 48 implants were inserted into the mandibles of six sheep following one of two drilling protocols: undersized preparation (US; n = 24) and nonundersized preparation (NUS; n = 24). Immediately after implant insertion, an abutment was placed on each implant and 36 implants were subjected to 10 sessions of dynamic vertical loads (1,500 cycles, 1 Hz) of 25 N or 50 N. Insertion torque value (ITV) was recorded at implant installation. Resonance frequency analysis (RFA) was measured at implant insertion and at each loading session. Fluorochrome was administered at day 17, and the animals were euthanized after 5 weeks. The removal torque values (RTVs) were measured, and samples underwent histomorphometric, µCT (microcomputed tomography), and fluorescence image acquisition analyses. The bone volume density (BV/TV), bone-to-implant contact (BIC), bone area fraction occupancy (BAFO), and fluorochrome stained bone surface (MS) were calculated. A linear mixed model analysis was performed, and Pearson paired correlation was calculated. RESULTS: Five implants from the NUS group failed, with a mean ITV of 8.8 Ncm and an RFA value of 57. The mean ITVs for US group and NUS group were 80.5 (± 14) Ncm and 45.9 (± 25) Ncm, respectively (P < .001). No differences were noted in the RFA values from the time of implant insertion until the end of the study. No differences in RTV, BV/TV, BAFO, or MS were observed between the groups. Intense new bone formation took place in the NUS group implants that were subjected to load. CONCLUSIONS: Undersized preparation of cortical bone ensured a greater BIC compared to a nonundersized preparation. Moreover, this study demonstrated that immediate loading did not interfere with the osseointegration process, but loading induced intense new bone formation in the NUS group. It is not recommended to immediately load the implants when the clinically perceived primary stability is lower than an ITV of 10 Ncm and an RFA value of 60. Int J Oral Maxillofac Implants 2023;38:607-618. doi: 10.11607/jomi.9949.

Intralesional corticosteroids as a treatment for restricted mouth opening in oral submucous fibrosis.

OBJECTIVES: Oral submucous fibrosis (OSF) is a chronic debilitating disease of the oral mucosa, associated with an increased risk of malignancy. The primary objective of this study was to evaluate the effectiveness of intralesional corticosteroid injection as a treatment modality for OSF. We also studied the correlation between the treatment outcome and a number of individual variables. STUDY DESIGN: A total of 230 histologically confirmed patients with OSF were included in the study, of which 116 patients with a 30 mm or less interincisal mouth opening were subjected to intralesional injections of 40 mg methylprednisolone at monthly intervals for 6 consecutive months. The effect of the treatment was assessed by evaluating the degree of improvement in mouth opening. RESULTS: All patients included in the study had a history of chewing areca nut. In paired comparison, statistically significant difference (t = -8.78; df = 115; P < .001) was observed in mouth opening over a period of 12 months in the patients who had corticosteroid injections. CONCLUSIONS: Intralesional corticosteroid injection is one of the most widely implemented interventions for OSF at present, particularly for those patients with palpable fibrous bands. The present study provides justification for the use of corticosteroids in improving mouth opening.