Rehabilitation using an implant supported overdenture with two implants inserted in the interforaminal region is the easiest and currently accepted treatment modality to increase prosthetic stabilization and patient satisfaction in edentulous patients. The insertion of implants to the weakend mandibular bone decreases the strength of the bone and may lead to fractures either during or after implant placement. The aim of this three dimensional finite element analysis (3D FEA) study was to evaluate the biomechanical effects of implant diameter in case of facial trauma (2000 N) to an edentulous atrophic mandible with two implant supported overdenture. Three 3D FEA models were simulated; Model 1 (M1) is edentulous atrophic mandible, Model 2 (M2), 3.5x11.5 mm implants were inserted into lateral incisors area of same edentulous atrophic mandible, Model 3 (M3), 4.3x11.5 mm implants were inserted into lateral incisors area of same edentulous atrophic mandible. In M1 and M2 highest stress levels were observed in condylar neck, whereas highest stress values in M3 were calculated in symphyseal area. To reduce the risk of bone fracture and to preserve biomechanical behavior of the atrophic mandible from frontal traumatic loads, implants should be inserted monocortically into spongious bone of lateral incisors area.
1 July 2017 in Journal of Oral and Maxillofacial Surgery
The aim of this study was to investigate the neurovascular bundle (NVB) position with cone-beam computerized tomography (CBCT). CBCT images of 345 patients were evaluated. The distance from the neurovascular bundle to the cemento-enamel junction (CEJ) was measured (DNB). The distance from mid-palatal suture to the alveolar crest was used to determine the palatal depth. Palatal junction angle (PA) was measured using the junction angle between the hard palate and alveolar crest. The relationships between the DNB and the palatal depth and between these two parameters and the PA were evaluated. Student’s t-test was used to analyze the differences in DNB related to gender, and the correlation between the DNB while Pearson correlation analysis was used to determine the correlation between the DNB and age (p = 0.05). The relationship between the DNB and the palatal depth, and the relationship between these two parameters and the PA were also evaluated using Pearson correlation analysis. Except at the canine and first premolar areas the DNB was positively correlated with the palatal depth. No significant relationship between the PA and DNB or with PVD was observed. The highest DNB was 14 mm at the first molar, and the lowest was 10.8 mm at the canine. Care is needed while rotating flap and harvesting the subepithelial connective tissue graft at the canine area because the neurovascular bundle passes approximately 11 mm apically to CEJ at the canine region.
Background and Objectives: Beta-thalassemia (BT) has a high prevalence in Mediterranean, Southeast Asian, and African countries. Studies stated that thalassemia is an endemic disease that causes significant health problems in Cyprus. This study aimed to measure the contact angle between the implant and blood samples from BT major patients and healthy individuals to compare the contact angles and wettability of Grade 5 titanium implant surfaces. Materials and Methods: Grade 5 titanium discs that were 10 mm in diameter were used since they mimic the surface of dental implants. Following receiving informed consent, blood samples were taken from the patients’ index fingers in each group with lancet needles and a photo of the contact angle between the blood samples and the titanium surface was taken; the collected blood was transferred to a titanium disc with a medical pipette. ImageJ software with a specific contact angle plugin was used for the contact angle measurements. Results: Theta-mean, theta-circular, and theta-ellipse values were compared between all groups, and no significant difference was found (p > 0.05). Conclusions: In this study, it was hypothesized that the patients’ rheological property of decreased deformability would affect the wettability of implant surfaces in vitro; however, no such finding was reached in this study. Since in-depth studies associated with dental implant success in BTM patients are absent in the literature and Cyprus is one of the Mediterranean countries with a high prevalence of BTM, this study was conducted to enrich the literature. While some systemic diseases may affect the contact angle between the implant surface and blood, it can be concluded that this condition was not present for BTM patients in our study. Last but not least, we emphasize that this experiment was done on a single surface type and the results can be totally different when using other surface types.
The purpose of the current study was to assess the biomechanical behavior of 5 different fixation schemes for unfavorable mandibular angle fractures using the three-dimensional finite element analysis method. Five different miniplate fixation schemes were modeled for the fixation of unfavorable mandibular angle fractures. A double parallel miniplate (M1), which was placed at the halfway point of the mandibular angle height; a 1/3 superior-positioned miniplate (M2); a single miniplate (M3), which was placed at the halfway point of the mandibular angle height (1/2 middle-positioned); a 1/3 inferior-positioned miniplate (M4); and an X-miniplate which was placed at the halfway point of the mandibular angle height (M5). The lowest mechanical stresses were detected in the double miniplate model when compared with the other schemes, whereas 1/3 inferior-positioned miniplate had the highest stress and displacement values. The authors suggest that the double miniplate is an adequate rigid fixation technique, whereas the 1/3 inferior-positioned miniplate configuration should not be used in case of unfavorable mandibular angle fracture.