Three-Dimensional Radiographic Evaluation of the Malar Bone Engagement Available for Ideal Zygomatic Implant Placement.

Zygomatic implant rehabilitation is a challenging procedure that requires an accurate prosthetic and implant plan. The aim of this study was to evaluate the malar bone available for three-dimensional zygomatic implant placement on the possible trajectories exhibiting optimal occlusal emergence. After a preliminary analysis on 30 computed tomography (CT) scans of dentate patients to identify the ideal implant emergencies, we used 80 CT scans of edentulous patients to create two sagittal planes representing the possible trajectories of the anterior and posterior zygomatic implants. These planes were rotated clockwise on the ideal emergence points and three different hypothetical implant trajectories per zygoma were drawn for each slice. Then, the engageable malar bone and intra- and extra-sinus paths were measured. It was possible to identify the ideal implant emergences via anatomical landmarks with a high predictability. Significant differences were evident between males and females, between implants featuring anterior and those featuring posterior emergences, and between the different trajectories. The use of internal trajectories provided better bone engagement but required a higher intra-sinus path. A significant association was found between higher intra-sinus paths and lower crestal bone heights.

Virtual quad zygoma implant placement using cone beam computed tomography: sufficiency of malar bone volume, intraosseous implant length, and relationship to the sinus according to the degree of alveolar bone atrophy.

The objective of this study was to investigate the malar bone volume and length that a zygomatic implant can engage, and the relationship to the sinus according to the degree of alveolar bone atrophy. A three-dimensional evaluation was performed using cone beam computed tomography scans from 23 patients with a totally edentulous maxilla; quad zygoma implants were virtually placed. The predictor variable was the amount of malar bone volume and length that a zygomatic implant can engage. The primary outcome variable was the relationship to the sinus according to the degree of alveolar bone atrophy. Other variables were the residual alveolar bone height to the floor of the sinus and the nasal cavity. The mean volume of malar bone engaged in this sample of 92 zygomatic implants was 0.19±0.06cm3. The implant had an extrasinus path in 60.9% of cases, a parasinus path in 25%, and an intrasinus path in 14.1%. The results suggest that the average volume of malar bone engaged by a zygomatic implant is constant regardless of implant position and the degree of alveolar bone atrophy. As alveolar atrophy increases, the trajectory of the implant becomes more parasinus and intrasinus. The examiners were able to find enough bone to adequately distribute the implants in all cases.

Implant Dentistry: Monitoring of Bacteria Along the Transmucosal Passage of the Healing Screw in Absence of Functional Load.

PURPOSE: To assess the changes in bacterial profile along the transmucosal path of healing screws placed immediately after insertion of two-piece endosseus implants during the 4-month osseointegration phase, in absence of functional load. MATERIALS AND METHODS: Two site-specific samples were collected at the peri-implant mucosa of the healing screws of 80 two-piece implants, for a total of 640 samples. Implants placement was performed following a single protocol with flapless technique, in order to limit bacterial contamination of the surgical site. Identical healing screws (5 mm diameter/4 mm height) were used for each of the 80 implants. During the 4 months of the study, the patients followed a standard oral care regimen with no special hygiene maneuvers at the collection sites. RESULTS: The present research documents that during the 4-month period prior to application of function load the bacterial profile of all sites exhibited a clear prevalence of cocci at the interface between implant neck and osteoalveolar crest margin. CONCLUSIONS: A potentially pathogenic bacterial flora developed only along the peri-implant transmucosal path.

Bucco-lingual Implant Path in the Posterior Mandible / 체질인류학회지

The purpose of this study is to investigate the cross -sectional anatomy of posterior mandibular body for proper determination of bucco -lingual implant path. Using fifty -four human mandibles, negative images of each mandible were made of agar impression material. The agar blocks were cut through the imaginary long axis of each root of three molars (M1M, M1D, M2M, M2D and M3). The depth of submandibular fossa, the angulation of long axis of mandibular body and tooth, and the length, angulation and ratio of alveolar bone superior to mylohyoid ridge and basal bone inferior to mylohyoid ridge were measured. The results obtained were as follows; 1. All of the measured angulations were decreased as it moves from M1M to M3. 2. The correlation coefficients among the angulation of the mandibular bone and the crown axis showed the high relationship (r=0.793), and the crown axis was steeper than the mandibular bone axis by 6.2 at M1M and 7.6 at M2M. 3. The length of upper alveolar bone was decreased, but that of inferior basal bone was increased as it moves from M1M to M3. 4. The depth of submandibular fossa was increased as it moves from M1M to M3. These results indicate that the angulation of implant path at the posterior mandible must be tilted more than wax -up crown axis by 6.2 at mesial root of 1st molar and by 7.6 at mesial root 2nd molar area for prevention of lingual cortical bone perforation during implant surgery.