Radiographic changes of trabecular bone density after loading of implant-supported complete dentures: A 3-year prospective study.

BACKGROUND: Bone tissues may undergo remodeling under functional mechanical stimuli. PURPOSE: This prospective study on implant-supported fixed complete dentures (IFCDs) evaluated the radiographic trabecular bone changes in density by means of gray levels and texture analysis variables after up to 3-year loading. MATERIALS AND METHODS: The sample consisted of digital periapical radiographs of 63 distal implants of hybrid IFCDs installed in 30 patients (22 women, mean age of 62 ± 7.8 years). Digital periapical radiographs were taken after prosthesis installation, and 1 and 3 years after IFCD loading. Longitudinal images of each implant were superimposed, and the same regions of interest were selected for measurement of gray levels statistics (mean gray levels, SD, and coefficient of variation [CV]) and texture parameters (correlation, contrast, entropy, and angular second moment). Data were analyzed by mixed regression models. RESULTS: Mean gray levels increased for 1 year (P < .05), for 3 years (P < .01) and for maximum bite force (P < .01). The interaction between bruxism and time in 1 year was significant (P < .01) for a decrease in CV. No significant effect of texture analysis variables was found (P > .05). CONCLUSIONS: The results suggest an increase of radiographic bone density as measured by an increase in mean gray levels and a decrease in CV in IFCD distal implants up to 3 years of loading.

Implant Inclination and Cantilever Length Are Not Associated with Bone Loss in Fixed Complete Dentures: A Prospective Study.

PURPOSE: To investigate whether the inclination of the most distal implant and the cantilever length influence marginal bone loss in implant-supported fixed complete dentures (ISFCDs). MATERIALS AND METHODS: A novel method using computed tomography images was developed to measure the mesiodistal implant inclination. The cantilever length was measured during ISFCD fabrication. Radiographs were obtained after ISFCD installation at 1 and 3 years after loading. RESULTS: A total of 30 subjects with 62 implants were included. Accumulated marginal bone loss was 0.35 ± 0.49 mm. No significant association was found between marginal bone loss and cantilever length or implant inclination. CONCLUSION: Implant inclination and cantilever length do not seem to affect marginal bone loss.

Risk factor model of mechanical complications in implant-supported fixed complete dentures: A prospective cohort study.

OBJECTIVES: This prospective cohort study estimated the effect of technical and clinical factors on mechanical complications in implant-supported fixed complete dentures (IFCDs). The patient's perception of the impact of oral rehabilitation on quality of life was assessed. MATERIAL AND METHODS: A non-probabilistic sample consisted of 88 consecutive patients treated with 94 screw-retained, metal-acrylic IFCDs. Data collection included sociodemographic variables, presence and intensity of bruxism, maximal occlusal force, opposing arch, design of the metallic framework, distribution of occlusal contacts, and quality of life (OHIP-14). IFCD-level data were analyzed using Kaplan-Meier survival analysis and Cox regression model. Quality of life data were analyzed by paired Student t test. RESULTS: During a mean follow-up of 35.1 ± 18.3 months, 16/94 IFCDs (17%) had repairable mechanical complications because of loosening/fracture of artificial teeth (n = 15) and screw loosening (n = 1). Framework design (retention pins <4 mm) was a significant risk factor for complications (HR = 11.038; p = 0.027) when adjusted for sex. Mechanical complications were not associated with sex, body mass index, thickness of the acrylic resin veneering, type of opposing arch, distribution of occlusal contacts and force, protrusion interference, presence/intensity of bruxism or maximal occlusal force. OHIP-14 total scores decreased after IFCD treatment for both patients with or without complications. CONCLUSIONS: Within the limitations of this study, the results suggest that clinical success is associated to framework design with retention pins equal or longer than 4 mm. Quality of life improved with IFCD treatment, even in patients with mechanical complications.