Objectives. To evaluate the success rate of bone grafts and implants carried out at the Latin American Institute for Research and Dental Education (ILAPEO), considering the following: (i) the different pure bone substitutes (autogenous, xenogeneic, and alloplastic), (ii) the presurgical bone height, and (iii) how the treatment is compromised when membrane perforation occurs during sinus lift in maxillary sinus surgeries. Material and Methods. The initial sample comprised 1040 records of maxillary sinus lifting surgeries. After evaluation, the final sample retained 472 grafts performed using the lateral window technique with a total of 757 implants. The grafts were divided into 3 groups: (i) autogenous bone ( n = 197 ), (ii) xenogenous bovine bone ( n = 182 ), and (iii) alloplastic material ( n = 93 ). One calibrated examiner classified the sample into two groups based on the residual bone height (<4 mm and ≥4 mm) of the area of interest measured on parasagittal sections of tomographic images. Data on membrane perforation occurrences in each group were collected; qualitative variables were described using frequency, expressed as percentages. The Chi-square test was used to analyze the success of the graft types and the survival rate of the implants as a function of the grafted material and the residual bone height. The Kaplan-Meier survival analysis was used to calculate the survival rate of bone grafts and implants according to the classifications adopted in this retrospective study. Results. The success rate of grafts and implants was 98.3% and 97.2%, respectively. There was no statistically significant difference in the success rate among the different bone substitutes ( p = 0.140 ). Only 8 grafts (1.7%) and 21 implants (2.8%) failed. There was a greater success rate for both grafts (96.5%) and implants (97.4%) when the bone height was ≥4 mm. The success rate in the 49 sinuses in which the membrane was perforated was 97.96% for the grafts and 96.2% for the implants. The follow-up periods after rehabilitation ranged from 3 months to 13 years. Conclusions. Within the limitations of the data analyzed in this retrospective study, maxillary sinus lift was a viable surgical technique that enabled implant placement with a predictable long-term success rate, regardless of the type of material used. The presence of membrane perforation did not interfere with the success rate obtained for grafts and implants.
The prosthetic management of a poor implant treatment is presented in this case report. The recommended occlusion concepts for implant-supported prostheses were applied for the resolution of the case. The rehabilitation of the posterior segments provided a mutually protected occlusion with adequate distribution of the axial and lateral bite forces with stable posterior occlusion. The clinical exam indicated the need for modification in the vertical dimension of occlusion. Sufficient interocclusal rest space was present to test the alteration in the vertical dimension. The aim was to achieve an occlusion scheme that followed four specific criteria: (1) centric contacts and centric relation of the jaw-to-jaw position; (2) anterior guidance only; (3) shallow anterior angle of tooth contact; and (4) vertical dimension of occlusion with acceptable tooth form and guidance. The success of an oral rehabilitation relies in following the aforementioned criteria, appropriate interaction between the dental laboratory technician and the clinician, careful elaboration of the provisional rehabilitation with all the desired details to be reproduced in the final prosthetic restoration and sufficient follow-up time of the provisional prostheses before placing the final restoration.
The aim of this retrospective study was to evaluate the long-term predictability of treatment using implants with hydrophobic and hydrophilic surfaces, according to clinical parameters and survival rates. Records from all patients who received dental implants between January 2013 and December 2014 at ILAPEO College were fully evaluated by two graduate dentists. Records with incomplete or unclear data were excluded from the study. The variables evaluated were demographic data, design of implants and prosthetic components, type of loading, data related to the patients' general health, and survival of implants and prostheses. The final retrospective sample comprised 776 patients with 2707 implants, with up to 5 years of follow-up. Survival rates of implants and prostheses were 97.93% and 98.77%, respectively. Implants with hydrophobic (97.87%) and hydrophilic (98.34%) surfaces exhibited similar survival rates. Considering the different types of loading, there was no statistically significant difference between loading protocols regarding implant survival rates. Unsuitable healing capacity, uncooperative and not motivated patient, loss of prosthesis, and peri-implant bone loss were confirmed statistically to be factors that may contribute to implant loss, according to hazard ratio and odds ratio. The present study showed similar and high overall survival rates for implant with both types of surfaces, in the long term. The surface treatment, implant model and loading protocol had no significant influence on implant loss. Therefore, the evaluated implant systems were able to offer a high predictability for both hydrophobic and hydrophilic implants.
The mechanical aspects of tightening screws over implants are important to ensure a successful prosthetic rehabilitation. Screw loosening is a common problem that can be avoided with passive adaptation of the components and an increased tensile force developed in the screw, a preload. Objective: This in vitro study evaluated the effect on preload of a carbon lubricant deposited on the surface of titanium alloy prosthetic screws: conventional Ti6Al4V and surface enhanced. Material and methods: Conventional titanium alloy prosthetic (n = 7) and carbon coating surface enhanced screws(n = 7) were compared. Each prosthetic screw supporting a metallic UCLA over an implant was tightened with the manufacturer’s recommended torque of 32 N.cm. The removal torque values, recorded for ten consecutive cycles of tightening and removal, were used to estimate the preload. Implant blocks were then sectioned and the interfaces were observed by light microscopy. Results: The lowest removal torque, and consequently the highest preload values, was achieved for the lubricated group in most cycles. The contacts between threads were located at the coronal aspect of all observed screw mating threads. Conclusion: Data indicate that the lower coefficient of friction of a carbon lubricant can generate higher preload. The machining precision observed produced the adaptation and regular contact interfaces.
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