This study aimed to evaluate cortical bone thickness of implant sites in the maxilla and mandible before & 5 months after surgery, using CBCT, to determine whether cortical bone thickness plays an important role in the Early remodeling and survival of implants under the influence of natural human chewing forces with a mixed diet, the underlying hypothesis is whether there will be changes in thickness of cortical bone after implanting due to normal chewing forces, and whether these changes will vary depending on the location of the implant in the jaw. The study started on Januray 10, 2024, in a dental clinic. It included 15 patients and 30 implant sites. All patients had two dental implants in different locations in the lower / upper jaws. The sample was divided into four groups: Group 1 anterior maxilla 4 patients, Group 2 posterior maxilla 10 patients, Group 3 anterior mandible 6 patients, and Group 4 posterior mandible 10 patients. This distribution unequal of patient's is a limitation to generalize the study results and obtain good precision for results. Masticatory force efficiency was measured on a mixed diet for all four groups using a filtration technique for chewed foods (carrots, bread, chicken meat, etc.). The mean and percentage of masticatory efficiency were measured for all patients. The CBCT scans were performed on 0.1 mm. Cortical bone thickness was measured by taking three measurements at the implant level using a CBCT scanner and White Fox v3.1 software for all patients before and 5 months after implantation. Before implant placement, the average chewing activity rate and efficiency rate for the entire sample was 44.75%. Five months after implant placement, this increased to 60.25%, showing a 15.50% increase. The mean masticatory forces before implantation were 212.02 ± 37.94 N, which increased to 216.32 ± 29.78 N after five months, indicating an average increase of 4.3 ± 8.16 N. Regarding cortical bone thickness five months after implant placement: Posterior upper jaw (Group 2): Mean ± SD was 0.60 ± 0.36 mm. Anterior upper jaw (Group 1): Mean ± SD was 0.60 ± 0.17 mm. Anterior lower jaw (Group 3): Mean ± SD was 1.30 ± 0.51 mm. Posterior lower jaw (Group 4): Mean ± SD was 1.30 ± 0.25 mm. Statistical analysis using Student's t-test showed significant differences (p < 0.05) in cortical bone thickness between the two periods (before and 5 months after implantation) at all measurement sites. sign of the differences indicated that cortical bone thickness values were lower five months after implantation compared to before implantation. Furthermore, significant differences were found in cortical bone thickness between the three measured locations (1 mm from the implant-abutment junction radially in the apical, lingual, and buccal directions), regardless of the study period. Specifically, cortical bone thickness was smaller in the buccal direction compared to the middle of the implant radially and the apical direction. Also, thickness in the apical direction was smaller than in the lingual direction, both before and after implantation. This results at 95% confidence & p < 0.05. Chewing function improved significantly after implant placement: the average chewing activity rate increased from 44.75% before implantation to 60.25% five months after. The average chewing force also slightly increased by about 4.3 N. Statistically significant cortical bone thickness reduction (resorption) was found across all measured sites five months post-implantation (p < 0.05 and 95% confidence level). Regarding the overall thickness before and after implantation: The lower jaw (both anterior and posterior) consistently showed greater cortical bone thickness (around 1.30 mm after 5 months) compared to the upper jaw (around 0.60 mm after 5 months). The highest average cortical bone resorption (greatest reduction in thickness) occurred in the posterior upper jaw (Group 2). The lowest average cortical bone resorption occurred in the posterior lower jaw (Group 4). In terms of spatial location around the implant, the buccal (cheek side) cortical bone was generally thinner than the lingual (tongue side) and apical (root tip side) regions, both before and after implantation. This study provides valuable, quantitative data on how cortical bone thickness changes at specific implant sites over a five-month period under the influence of normal chewing forces. It confirms that CBCT is a superior tool for monitoring these changes compared to older imaging methods. Crucially, the research specifically identifies the posterior upper jaw as the region most susceptible to cortical bone resorption post-implantation, while the posterior lower jaw is the most stable. This insight directly informs clinical planning by flagging high-risk areas.
Merzouk et al. (Wed,) studied this question.