Evaluation of Bone Width Lateral to the Mandibular Canal as an Alternative Approach for Implant Installation (original) (raw)
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Background/aim: Dental Implant therapy has become an integral part of daily practice due to its high successrate but surgical mishaps, complications and damage of vital anatomical structures do occur. If proper diagnosis and treatment planning is done then implant surgeries can proceed uneventfully and can fulfil both the functional and aesthetic demands after osseointegration. The aim of this study was to determine the longest upright and tilted implants allowed to be placed in three posterior mandibular teeth areas in case of Immediate Implant Placement (IIP) with respect to a safe distance from the inferior alveolar canal (IAC) and the submandibular fossa, using cone beam computed tomography (CBCT). Materials and Method: The 209 CBCT scanswere reviewed retrospectively of the subjects. The following were measured: distance from the tooth apex to the IAC, buccolingual width of the mandible which was determined at the axial section nearest to the middle of tooth?s mesiodistal width, classification of mandibular cross-sectional morphology as per Sammartino et al (2008) and Chan H-L (2011),upright and tilted implant placement simulation, tilting anglethat allowed placement of the longest implant and availability of buccal and lingual cortical plate. Results: As we progress posteriorly i.e., from second Premolar (PM) to Second Molar (M) the distance from tooth apex to IAC decreases significantly. The mean value between the teeth is increasing significantly. The mandibular cross-sectional ridge types are U (undercut), C (convergent); P (parallel) had a prevalence rate of 65%, 23%, and 14% respectively. The available width for both buccal and lingual cortical plate increased significantly from 2PM to 2M. For the moreposterior regions the tilting angle was greater in orderto place the longest implant without causing any lingual perforation and damage to vital anatomic structures like the IAC. Conclusions: Within the scope of this study, we have concluded that the distance from the tooth apex to IAC decreases in molar region as compared to premolar region. Whereas, buccolingual width of the mandible is greater in molars as compared to the premolars. Mandible has a tendency to be classified as ?undercut? in more posterior regions. Therefore, there is a need for careful attention when the placement of an immediate implant is planned in this area. Alternative treatment option to avoid the violation of the lingual plate perforation includes the use of implant tilting. More posterior regions resulted in a restriction to place shorter implants in comparison to more anterior regions.
The Scientific World Journal
Objective. To determine the morphological features in the anterior mandibular region, the presence of lingual foramen and canal dimensions in Saudi subjects that would interfere with standard implant placement. Methods. CBCT scans of patients seeking implant treatment were examined. Based on the dentition status, patients were categorized into edentulous (group I) and dentulous (group I). On the panoramic view, the distance between the two mental foramina was divided into vertical segments of 10 mm width. In each segment, vertical bone height and buccolingual thickness at three levels (alveolar crest, 5 mm, and 10 mm apical to the crest) were assessed. The lingual foramen prevalence and canal features were assessed as well. Comparisons between the two groups regarding the assessed parameters were performed using the t-test. The percentage of edentulous mandibles with thickness <6 mm corresponding to the standard implant diameter was also calculated. Results. Following the inclusi...
Annals of Anatomy - Anatomischer Anzeiger, 2016
The aim of this study has been to evaluate and correlate the anatomical features of the posterior mandibular region (submandibular fossa depth, bone height and thickness, and mandibular canal corticalization) to improve accident prevention and allow safe planning in implantology. Four parasagittal sections of cone-beam computed tomography (CBCT) from 100 patients were bilaterally analyzed. Linear measurements of the submandibular fossa depth and bone height and thickness were performed. The submandibular fossa was also classified into non-influential undercuts and influential undercuts for implant placement. Mandibular canal corticalization was also evaluated and classified according to the visualization. Data on patient age and gender were also collected. Forty-one scans (41%) were from male patients, and 59 (59%) were from female patients. Patient age ranged between 18 and 84 years, with an average age of 51.37 years. The submandibular fossa depth and implant bone thickness had a significant effect on the variability of the sample (46.1% and 22.3%, respectively). The submandibular fossa depth was quite variable, and the highest values were observed in the posterior regions. In 18.27% of the cases, the presence of the fossa directly influenced implant placement, considering a bone height of 10 mm (standard implant). A significant correlation was observed between fossa depth and bone thickness. Thus, greater attention should be paid to thick ridges; although thick ridges are favorable, they may be associated with deeper submandibular fossae. The mandibular canal was the most influential anatomical structure in the premolar region due to the reduced bone height in this region and the greater difficulty in viewing the canal, and the submandibular fossa was the most influential structure in the molar region due to lower bone height leading up to the fossa and the greater fossa depth in this region. Therefore, CBCT is an important tool for assessing the mandibular region and planning for safe implant installation in the posterior mandible. Furthermore, comprehensive evaluation of the characteristics of this region is necessary, as the variablessubmandibular fossa depth, bone height and thickness, and mandibular canal corticalization-are related and must be considered together when planning.
Journal of Indian Orthodontic Society
Aim: The purpose of this study was to use measurements from cone beam computed tomography scans to quantify the cortical bone thickness of mandibular buccal shelf region and preferable site for buccal shelf implant placement in 10 hyperdivergent and 10 hypodivergent patients. Method: 20 cone beam computed tomographies were equally divided based on divergence. 6 sites were examined: mesial of first molar (6M), middle of first molar (6Mi), interdental between the first and second molar (Id), mesial of second molar (7M), middle of second molar (7Mi), and distal of second molar (7D). The study quantified the mandibular buccal shelf relative to its angle of slope, the cortical bone thickness measured perpendicular to the bone surface, the amount of cortical bone 30° angle to the bone surface. The cortical bone thickness was measured perpendicular and at a 30° angle at 3, 5, and 7 mm from the alveolar crest. Result: Significant change is seen at the buccal shelf slope at 6M ( P = .001) an...
Cureus
Introduction: The posterior mandibular region, due to the presence of vital structures, poses a high risk during implant placement because of its susceptibility to neurovascular injury and perforation of the lingual cortex. A breach in implant length and available bone height may lead to serious intraoperative and postoperative complications. Prediction of the exact location of the inferior alveolar nerve and submandibular fossa anatomy is a prerequisite for ideal implant placement, which is always not possible with conventional radiographic and clinical techniques. Materials and methods: One hundred ten cone-beam computed tomographies (CBCTs) of patients were acquired from the radiological archives of a radiological center in Chennai. DICOM files from CBCT were exported to Bly Sky Plan software. Cross-sections of the second molar and first molar were extracted following the inclusion criteria. The linear dimension between the mandibular canal and mylohyoid ridge and anatomic variables of the submandibular fossa were measured digitally on the left and right sides using software measuring tools. Descriptive statistics were done. The unilateral and bilateral site and gender differences were evaluated. Bone height superior to the mandibular canal was correlated with the submandibular fossa parameters; depth of undercut in the vertical and horizontal directions; and angle of the undercut. Results: The mandibular canal was on average 5.5 mm and 4 mm inferior to the Mylohyoid ridge in the second molar region and first molar region, respectively, with the right and left sides showing no statistically significant difference. The depth of fossa undercut in vertical and horizontal dimensions was higher in the second molar region compared to the first molar region. The height of the deepest point of the undercut in the vertical dimensions showed a positive correlation with the bone available between the mandibular canal and the mylohyoid ridge. Conclusion: Keeping 2 mm of safety factor in consideration, implants can be safely placed up to the mylohyoid ridge in 100% of cases and 2 mm below the mylohyoid ridge in 78.9% of cases in the mandibular second molar region. In keeping with a safety factor of 2 mm, implants can be safely placed up to the mylohyoid ridge in 82.6% of cases and 2 mm below the mylohyoid ridge in 43.1% of cases in the first molar region. A more pronounced undercut was seen in the second molar region than in the first molar region. Deeper fossa undercuts in vertical dimension are associated with more inferior positioning of the mandibular canal.
The Journal of Contemporary Dental Practice
Aim: The accurate placement of implants in mandible requires consideration for angulations of the bone along with the vertical dimensions. The aim of this present study was to assess the variation of mandibular anatomy using computed tomography (CT) radiography and to evaluate the effect of presence and absence of teeth on the mandibular anatomy before planning an implant surgery. Material and methods: The present population-based retrospective study was conducted using 167 digital CT scan images those selected from departmental archives. The samples were subdivided two groups: group 1included digital CT of edentulous mandible while group 2 included digital CT of edentulous mandible. The axial height, vertical height, and angulations were recorded separately for each group. Results: The results of the present study showed a gradual increase in mandibular angle in both the groups with a statistically significant difference only in the canine-premolar area. The axial height showed a significant difference at canine and first premolar area and a second premolar and the first molar area. However, available height showed a significant difference in canine and first premolar area and distal to the second molar area. When both the sides were compared, no statistically significant difference was observed between right and left sides. Conclusion: It was concluded that due to the variability of the mandibular anatomy and because of the effects of various imperative factors, 3D imaging like CT scans should be recommended for safer and secure presurgical planning. Clinical significance: In surgical osteotomies and implant placement especially in post-extraction sockets, two-dimensional (2D) image of panoramic radiographs should not be considered that reliable as these three-dimensional (3D) imaging radiographs. Therefore CT scans of various angulations and sections must be considered by the clinicians to rationally study the mandibular anatomy and their risk associated areas.
Evaluation of mandibular implant sites: correlation between panoramic and linear tomography
Braz Dent J, 2003
The reliability of the linear tomography and panoramic radiography made with X-ray equipment was evaluated (Vera View Scope X-600; Morita). The sample was composed of 20 dry human hemimandibles, in which the area selected for analysis was 1.5 cm distal from the limit set before the mental foramen. Four measurements were made. The images obtained were drawn on acetate paper and the hemimandibles cut at the demarcated area. The measurements were made using a digital electronic pachymeter. The values found for the radiographic images were compared to those obtained in the mandibular specimens and submitted to statistical evaluation by the Wilcoxon test. It was concluded that both techniques were reliable for the accomplishment of vertical linear measurements in the selected area. However, a 2.0 mm safety margin is recommended.