Reinforced PTFE Meshes Versus Customized Titanium Meshes

Overview

The objective of this study is to compare two surgical techniques for the treatment of the maxillary and mandibular bone atrophies.. Therefore, the main purpose is to compare the (i) the percentage of post-operative complications (ii) the three-dimensional bone gain with customized titanium meshes (test group - the medical device is digitally designed and made with customized laser sintering modality, customized to the defect of each patient) and with titanium-reinforced PTFE mesh (control group - the medical device is cut, shaped, and manually modelled to the patient's defect by the operator himself.

The rationale of the study is based on the fact that manual intra-operative modelling of a titanium-reinforced PTFE mesh is operator-dependent, and even in the case of very experienced operators it is always difficult, inaccurate and slow. The use of pre-modelled and pre-fabricated custom-made meshes with bevel margins and three-dimensional morphology adapted to the bone defect, would make it possible to carry out an important bone regeneration as it reduces the operating times, the risks linked to mesh borders, trauma to the soft tissues and the discomfort for the patient. This study aims to evaluate, in cases of maxillary and mandibular atrophies characterized by a vertical and / or combined resorption of the alveolar bone, the complication rate (intra- and post-operative) and the three-dimensional bone gain after traditional bone regeneration, where the medical device necessary for bone regeneration is cut out, shaped, and manually modelled by the operator, compared to digital bone regeneration. Subsequently, the medical device is digitally designed and made with a computerized method. The primary objective of the study is, therefore, the evaluation of the healing complications; in particular, the early or delayed exposure of medical devices used for bone regeneration, during the healing period. This exposure is, as reported in all clinical studies, the main cause of the failure of the surgery. A secondary objective, is the quantitative assessment of bone regeneration obtained by the 2 techniques. In particular, the evaluation of the reconstructed bone volume (RBV) with respect to the planned bone volume (PBV). Other targets include the qualitative evaluation of bone regeneration through histological and histomorphometric analysis of the bone biopsies obtained at the moment that the medical device is removed and finally the evaluation of the peri-implant bone resorption will be conducted over time. This clinical trial, which is promoted by Prof. Giuseppe Corinaldesi and the Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, is designed as a pilot, randomized, multicentric, independent, parallel-group clinical trial, in which the all variables will be analysed prospectively. The study will have a selection and enrolment period of approximately 12 months and a treatment period of approximately 24 months. As a result, the overall duration of the study will be approximately 36 months. Over the three-year period 2019/2021, it will include the treatment of 50 patients in good general health conditions who are affected by partial edentulism of the maxilla or mandible with vertical and horizontal resorption of the alveolar bone, which requires a prosthetic rehabilitation supported by implants to improve function and aesthetics of edentulous areas. Patients will be divided into 2 study groups, according to the previously computer-generated randomization sequence the following will be assigned to each group: group A (control), 25 patients who will be treated with bone regeneration with titanium-reinforced PTFE mesh, shaped and manually modelled by the operator during surgery; group B (test), 25 patients will be treated with bone regeneration with titanium mesh, designed and produced before surgery. The study will include 3 different treatment phases: the first phase (T0) involves bone regeneration using a standard technique (group A) or digital technique (group B); the second one (T1), subsequently, after 6 months, this will forsee the removal of the regeneration devices and the insertion of the implants; the third (T2), 3 months after the aforementioned, will forsee the final functional loading of the implants, with a consequent follow-up of the regenerated bone. All the materials and tools that will be used in the study are CE certified (with the exception of the custom-made mesh which, as a custom-made device, does not require CE certification) and have already been used in the normal care path for patients who have undergone bone regeneration. Moreover, the control visits and the radiological investigations of the data foreseen by the aforementioned protocol will be collected; They will be summarized in the case report form (CRF), and are those that characterize the normal care path of patients undergoing necessary bone regeneration for prosthetic implant rehabilitation when the bone quantity is insufficient. The primary objective of this study is to evaluate the non-inferiority of technique B (digital technique) compared to technique A (traditional technique) in the incidence of complications. The Secondary objectives include: assessment of patient and operator benefits, reconstructed bone volume (RBV) compared to planned bone volume (PBV), histological and histomorphometric analysis of bone quality obtained and peri-implant bone resorption after 12 months of follow-up. The sample size necessary to support the null hypothesis is 17 subjects for each group. In order to compensate for any protocol deviations or possible drop-outs, the number of patients was increased to 25 per group. The results obtained in the two study groups will be subjected to descriptive statistical analysis and the differences between groups will be tested by means of appropriate statistical tests for purely exploratory and non-demonstrative purposes. The patient will be considered as the statistical unit of the analysis, and the statistical significance will be set at α = 0.05. The collected data will be grouped and summarized with respect to the demographic, anamnestic, and clinical variables of each patient. Exploratory analyses will be performed using descriptive statistics. The data will be presented both for the intent-to-treat population and for the per-protocol population. The sample size necessary to support the null hypothesis is 17 subjects for each group. In order to compensate for any protocol deviations or possible drop-outs, the number of patients was increased to 25 per group. The sample size was calculated using dedicated statistical software (STATA, StataCorp LLC) through Pearson's chi-squared test, guaranteeing a level of significance of 95% and a power of 80%.