Three-Dimensional Evaluation of Autogenous Ramus Block Graft Donor Site and Its Relation to Mandibular Canal.

Sufficient bone volume is necessary for placing a dental implant in an ideal position. To restore severely insufficient bone volume, autogenous block graft procedures with various intraoral donor sites are presented in the literature. The aims of this retrospective study are to present the dimensions and volume of the potential ramus block graft site, and to evaluate possible effect of mandibular canal diameter and its position in relation to mandibular ramus block graft volume. Two-hundred cone-beam computed tomography (CBCT) images were evaluated. The maximum length, width, height, and volume of the potential ramus block graft site, mandibular canal diameter, mandibular canal-mandibular basis distance, and mandibular canal-crest distance were measured. Mandibular canal diameter, mandibular canal-crest distance, and mandibular canal-mandibular basis distance were 3.139 ± 0.446 mm, 15.376 ± 2.562, and 7.834 ± 1.285 mm, respectively. In addition, the dimensions of the potential ramus block graft sites were measured 11.156 ± 2.297 mm × 10.390 ± 3.420 mm × 8.816 ± 1.720 mm (height × length × width). Moreover, the potential ramus bone block volume was calculated as 1.076 ± 0.398 cm3. While a positive correlation was detected between mandibular canal-crest distance and the potential ramus block graft volume (r = .160, P = .025), a negative correlation was found between mandibular canal-mandibular basis distance and the potential ramus block graft volume (r = -.020, P = .001). Mandibular ramus is one of the predictable intraoral donor sites for bone augmentation procedures. However, ramus has some volumetric limitations related to its neighboring anatomic structures. It seems to be important to evaluate lower jaw in a 3-dimensional manner to prevent surgical complications.

Association between ridge morphology and complexity of implant placement planning in the posterior mandible.

STATEMENT OF PROBLEM: Uncertainties regarding the 3D ridge morphology of the posterior mandible can greatly increase the risk of surgical complications during dental implant placement. By using cone beam computed tomography (CBCT) imaging and a computer-guided implant treatment software program before any invasive procedure, it is possible to assess ridge morphology and understand the surgical complexity and risk level. PURPOSE: The purpose of this radiological clinical study was to evaluate a large series of CBCT images to evaluate ridge shape variations along posterior mandibular edentulous regions and to clarify their associations with the level of implant planning complexity. MATERIAL AND METHODS: One hundred and twenty CBCT files were analyzed retrospectively for a total 240 hemimandibular sites. Images of each edentulous region of the mandibular first and second premolar and first and second molar sites were evaluated in the sagittal plane. Ridge morphology and implant planning complexity per site were assessed. Categorical variables were presented as number of events and percentages. The chi-square test was used to compare the categorical variables (P=.05). RESULTS: Of 491 partially edentulous mandibular sites, 235 were on the right, and 256 were on the left. Forty-two sites had a distal adjacent tooth, while 266 sites had no distal adjacent tooth. The sagittal bone sections demonstrated oblique (40.53%), straight (31.77%), S-shape (24.24%), hourglass (2.44%), and basal bone (1.02%) ridge morphologies. Implant complexity was deemed straightforward in 66.19% of sites, while 31.6% were identified as advanced and 2.54% as complex. When ridge morphology was evaluated from straight to basal-round bone shape, the implant complexity followed the same trend of change from a straightforward to complex procedure (P=.001) for edentulous second and first molar regions. No significant differences were noted at edentulous second premolar sites (P=.063). The missing second molar sites with oblique morphology were predicted to have 60.9% straightforward complexity, and first molar sites with oblique morphology had 55.8% straightforward implant complexity. Second premolars with straight ridge morphology had 71.7% straightforward complexity, whereas first premolars with the same shape had 92.5% straightforward implant complexity. CONCLUSIONS: Careful evaluation of sagittal CBCT images can provide significant clinical information regarding ridge shape and anticipated surgical complexity before and at the time of implant placement. Surgical complexity is greatest at the most posterior mandibular edentulous sites, and extra attention and caution should be exercised during the surgical planning phases of implant surgery.

Impact of bisphosphonate drugs on dental implant healing and peri-implant hard and soft tissues: a systematic review.

OBJECTIVE: Implantology represents the gold standard for oral rehabilitation, unfortunately, often, despite there are no local contraindications to this type of rehabilitation, there are uncertainties regarding the general health of our patients. Many patients nowadays take bisphosphonate drugs, often without first seeking advice from an oral surgeon or a dentist. The purpose of this review is precisely to highlight any contraindications to this type of treatment reported in the literature, in patients who take or have taken bisphosphonate drugs. METHODS: For this study the scientific information sources were consulted using as search terms "("bisphosphonate AND "dental implant")", obtaining 312 results, these were subsequently skimmed according to the inclusion and exclusion criteria, and further evaluated their relevance to the study and the presence of requested outcomes. RESULTS: Only 9 manuscripts (RCTs, Multicentric studies and Clinical Trials) were included in this review, as they respected the parameters of this review, they were analyzed and it was possible to draw important results from them. Surely from this study it is understood that the use of bisphosphonate drugs does not represent an absolute contraindication to implant therapy, it is evident how adequate pharmacological prophylaxis, and an adequate protocol reduce the risks regarding implant failures. Furthermore, the values of marginal bone loss over time seem, even if not statistically significant, to be better in implant rehabilitation with bisphosphonate drugs association. Only a few molecules like risedronate, or corticosteroids, or some conditions like smoking or diabetes have shown a high risk of surgical failure. CONCLUSION: Although this study considered different studies for a total of 378 patients and at least 1687 different dental implants, showing better results in some cases for dental implant therapy in cases of bisphosphonate intake, further clinical, randomized and multicentric studies are needed, with longer follow-ups, to fully clarify this situation which often negatively affects the quality of life of our patients and places clinicians in the face of doubts.

Treatment of Excessive Gingival Display by Using Botulinum Toxin-A Targeting Yonsei Points and Zygomatic Major Muscles.

ABSTRACT: The aim of this clinical report is to present satisfying and unsatisfying treatment results of a patient with excessive gingival display (EGD) treated via botulinum toxin injections in different time points. A 22-year-old male patient referred to the Department of Periodontology with a complaint of EGD. The patient opted the treatment with botulinum toxin-A injections. During the first treatment, injections at Yonsei points were performed. After the first EGD treatment, the patient did not satisfy with his smile. The closure of gingival display was not sufficient, especially in posteriors. However, he did not demand for reinjection. Six months after the first treatment, he was advised to have 2 injection points per side including zygomatic major muscles as well as Yonsei points. Two weeks after the second treatment, the patient totally satisfied with his new smile. Yonsei point is a safe and repeatable injection point for the practitioners. However, the authors suggested injections targeting zygomatic major muscles as well as Yonsei point injections to treat the patients with mixed EGD.

Treatment of Various Types of Gummy Smile With Botulinum Toxin-A.

The objective of this article is to present 3 various types of gummy smile treated with botulinum toxin-A injection per site at Yonsei points. The patients, who visited the department to demand a more aesthetic smile, were classified according to gummy smile type: asymmetric, anterior, and mixed. Botulinum toxin-A injection at Yonsei point was considered. Preinjection and postinjection pictures were taken, and the severity of excessive gingival display was measured for each tooth between second premolars. Two weeks after botulinum toxin injections, no complication was noted. The amount of excessive gingival display for each tooth between second premolars was measured less than 3 mm, and the percentage of improvement for each case was calculated 100%. The botulinum toxin injection at Yonsei point may be a predictable and noninvasive treatment option for various types of gummy smile.

Radio-Morphometric Evaluation of Greater Palatine Canal and Pterygopalatine Fossa Component: Maxillary Anesthetic Implications.

This is a retrospective analytical cross-sectional study involving 131 cone-beam computed tomography (CBCT) scans of adult (18-99 years) that assessed greater palatine canal (GPC) attributes (length, curvature angle, diameter of curvature) and the type of the trajectory of GPC-pterygopalatine fossa (PPF) component. The GPC is an important landmark that connects the oral cavity and PPF. It contains greater and lesser palatine nerves, along-with descending palatine artery and vein by extending from the inferior part of the PPF to the hard palate. The GPC acts as a pathway for infiltration of local anesthesia. The inferior orbital fissure (IOF) is in close proximity to these vital anatomic structures and hence accurate identification of its location during regional block anesthesia is crucial. This is one of the very few studies investigating these important structures on CBCT scans highlighting the importance of preoperative scans for the anatomic determination. The images were analyzed for the lengths and anatomic paths of the right and left GPC-PPF in sagittal plane. The diameters of the upper (higher bony aspect of PPF) and lower openings (GPC opening) displayed statistically significant differences in the comparison between males and females (P < 0.05). Overestimation or underestimation of the GPC length can cause a lack of anesthesia and undesirable diffusion of the anesthetic solution into the orbit thorough the IOF causing diplopia, or into the cranial cavity. A thorough understanding of GPC length and pathway types is obligatory for proper anesthetic administration and performing any maxillofacial procedures.

The Relationship between Maxillary Sinus Lateral Wall Thickness, Alveolar Bone Loss, and Demographic Variables: A Cross-Sectional Cone-Beam Computerized Tomography Study.

OBJECTIVES: Sinus floor elevation and augmentation surgery is widely used as a reliable procedure to increase insufficient bone height in the posterior maxillary area. The purpose of the present clinical study was to determine the associations between periodontal bone loss (PBL), maxillary sinus lateral bone wall thickness, age, and gender using cone-beam computerized tomography (CBCT). MATERIALS AND METHODS: The current retrospective study consists of 716 maxillary sinus CBCT images of 358 patients. The CBCT scans were assessed to detect the relationship between lateral wall thickness and PBL. ANOVA and Student t test analysis were used to determine the influence of PBL on sinus lateral wall thickness. RESULTS: Sinus lateral wall thickness was significantly associated with PBL (p < 0.05) at 3, 13, and 15 mm height. There was no significant association between lateral wall thickness and gender (p > 0.05). However, there was a significant association between lateral wall thickness at 3 and 13 mm and age (p < 0.05). There were significant associations between PBL and age (p < 0.001), and PBL and gender (p < 0.05). CONCLUSIONS: PBL might have an association with maxillary sinus lateral bone wall thickness. Further studies are needed to confirm this possible relationship.

Assessment of morphological and anatomical characteristics of mental foramen using cone beam computed tomography.

PURPOSE: To determine the shape, position, vertical height, surrounding bone characteristics, and opening angle of mental foramen (MF) using dental cone beam computed tomography (CBCT). METHODS: A retrospective study was performed on 663 patients. CBCT records analyzed for the shape, position, and surrounding bone measurements of the MF using Simplant 3D software (Hasselt, Belgium). Opening angle of MF was also assessed. Kruskal-Wallis and Mann-Whitney U tests were employed to test significant differences between parameters, genders and ages. RESULTS: All mental foramina were visualized. Regarding location, 49.2% of the MFs were located between first and second premolars, 7.7 distal and 39.7% coincident to the apex of the mandibular second premolar. The mean MF opening angle was 45.4° on the right side, and 45.9° on the left. There were no statistically differences between gender groups with regard to the opening angle degrees. CONCLUSIONS: This study may provide useful information about variations in the position, shape and size, angle of mental foramen, which may help the practitioners to perform safer mental nerve blocks and surgical procedures.

Accessory Mental/Buccal Foramina: Case Report and Review of Literature.

The presence of the additional mental foramen of the mandible is considered to be a rare anatomical occurrence. Only a few cases have been reported. In these cases, only 1 foramen is called the mental foramen and the others are termed either accessory mental foramen or accessory buccal foramen. The purpose of this article was to present a case with computed tomography images and suggest that preoperative cone beam computed tomography should be performed to detect any anatomical variation. In addition, we present all reasonable terminology to ease the communication through unique terminology among surgeons.

Effect of Porous Titanium Granules on Bone Regeneration and Primary Stability in Maxillary Sinus: A Human Clinical, Histomorphometric, and Microcomputed Tomography Analyses.

The aim of this randomized controlled study was to comparatively analyze the new bone (NB), residual bone, and graft-bone association in bone biopsies retrieved from augmented maxillary sinus sites by histomorphometry and microcomputed tomography (MicroCT) in a split-mouth model to test the efficacy of porous titanium granules (PTG) in maxillary sinus augmentation. Fifteen patients were included in the study and each patient was treated with bilateral sinus augmentation procedure using xenograft (equine origine, granule size 1000-2000 µm) and xenograft (1 g) + PTG (granule size 700-1000 µm, pore size >50 µm) (1 g), respectively. After a mean of 8.4 months, 30 bone biopsies were retrieved from the implant sites for three-dimensional MicroCT and two-dimensional histomorphometric analyses. Bone volume and vital NB percentages were calculated. Immediate after core biopsy, implants having standard dimensions were placed and implant stability quotient values were recorded at baseline and 3 months follow-up. There were no significant differences between groups according to residual bone height, residual bone width, implant dimensions, and implant stability quotient values (baseline and 3 months). According to MicroCT and two-dimensional histomorphometric analyses, the volume of newly formed bone was 57.05% and 52.67%, and 56.5% and 55.08% for xenograft + PTG and xenograft groups, respectively. No statistically significant differences found between groups according to NB percentages and higher Hounsfield unit values were found for xenograft + PTG group. The findings of the current study supports that PTG, which is a porous, permanent nonresorbable bone substitute, may have a beneficial osteoconductive effect on mechanical strength of NB in augmented maxillary sinus.

Management of Limited Vertical Bone Height in the Posterior Mandible: Short Dental Implants Versus Nerve Lateralization With Standard Length Implants.

Inferior alveolar nerve lateralization (IANL) and short dental implants (SDI) are 2 viable implant-based treatment approaches in the presence of atrophied posterior mandible. Despite the risks of dysfunction, infection, and pathologic fractures in IANL, it becomes possible to place standard implants. The purpose of this study was to compare SDI and IANL approaches from clinical and radiographic aspects. Fifteen subjects having unilateral atrophic mandibles were allocated to SDI and IANL treatment groups. Following surgical procedures, early postoperative complications, implant survival, and periimplant clinical and radiographic parameters including probing pocket depth, attachment level, keratinized tissue amount, vertical tissue recession, and marginal bone loss were recorded at baseline and 1-year after prosthetic rehabilitation. In both groups, no implant was lost. Except usual postoperative complications, 2 patients had transient paraesthesia after IANL. According to time-dependent evaluation, both groups showed significant increase in probing pocket depth and attachment level at 1-year follow-up compared with baseline (P < 0.05). Except a slight but significant increase in mesial surface of SDI group (P < 0.05), no remarkable time-dependent change was identified in vertical tissue recession. Keratinized tissue amount did not exhibit any inter- or intragroup difference during whole study period. Marginal bone loss did not show any difference between IANL and SDI groups at follow-up. SDI placement or standard length implant placement with IANL can be considered promising alternatives in the treatment of atrophic mandibular posterior regions. However, SDI may be preferred in terms of lower complication risk.

Combined Endodontic and Surgical Treatment of Dens Invaginatus-Associated Extraoral Fistula: A Case Report with Seven-year Follow-up.

Dens invaginatus (dens in dente) is a developmental malformation of permanent or deciduous teeth that has various complex forms. It most commonly affects permanent maxillary lateral incisor teeth, and rarely affects the mandibular teeth. In this report, a rare case of dens invaginatus of a mandibular lateral tooth with an extraoral fistula is presented. A 10-year-old patient was referred to our clinic with extraoral symptoms that could not be diagnosed by medical doctors. Successful treatment with endodontic treatment and periapical surgery is described. Seven-year follow-up of the case is provided.

Do Porous Titanium Granule Grafts Affect Bone Microarchitecture at Augmented Maxillary Sinus Sites? A Pilot Split-Mouth Human Study.

BACKGROUND: The aim of this randomized controlled clinical study was to analyze the bone microarchitecture at augmented maxillary sinus sites by using different materials in patients to compare the effect of porous titanium granules as a sinus augmentation material with bone microstructural features. MATERIALS AND METHODS: Eight subjects with bilateral atrophic posterior maxilla of residual bone height <4 mm included in this study and each patient was treated with bilateral sinus augmentation procedure using xenograft with equine origin (Apatos, Osteobiol; Tecnoss Dental) and xenograft (1 g) + porous titanium (1 g) granules (Natix; Tigran Technologies AB). Sixteen human bone biopsy samples were taken from patients receiving two-stage sinus augmentation therapy during implant installation and analyzed using microcomputerized tomography. Three-dimensional bone structural parameters were analyzed in details: tissue volume, bone volume, percentage of bone volume, bone surface and bone surface density, bone specific surface, trabecular thickness trabecular separation, trabecular number, trabecular pattern factor, structural model index, fractal dimension, and bone mineral density. RESULTS: No statistically significant differences were found between groups according to bone structural parameters. CONCLUSIONS: Porous titanium grafts may ensure a space for new bone formation in the granules, which may be a clinical advantage for long-term success.

Relationship of Maxillary Sinus Volume and Nasal Septum Deviation: A Cone Beam Computed Tomography Study.

The present study was designed to test the hypothesis that there would be a correlation between nasal septum deviation (NSD) and a decreased maxillary sinus volume (MSV) in a Colombian population, using Cone Beam Computed Tomography (CBCT); other sinusal anatomical structures found during the reading were described and analyzed. A retrospective analysis of 537 CBCT scans of adult patients taken between January 2014 and January 2017 included measuring the maxillary sinus diameter in the vertical, horizontal, and sagittal planes. NSD was quantified and related to MSV using the same field of view (FOV). The volume of the right and left maxillary sinuses showed a median and interquartile range (IQR) of 8.18 mm3 (IQR: 6.2-10.33) and 8.3 mm3 (IQR: 6.4-10.36). Statistically significant differences were observed between sex and right and left MSV (p = 0.000), with higher MSV in men. The presence of NSD was observed in 96.81% of the sample and was evaluated in degrees, observing a median of 11° (IQR: 7-16) where 40% of the sample had moderate angles (9-15°). There was no correlation between NSD and a decreased MSV in the population studied. Detailed CBCT analysis with a large FOV is crucial for the analysis of anatomical structures before performing surgical procedures that involve the MS as a preventive diagnostic and therapeutic step for appropriate treatment.

Assessment of Radiodensity at Mandibular Periapical Bone Sites using Three-Dimensional Cone-Beam Computed Tomography.

Objectives: The aims of this retrospective study were to objectively assess bone density values obtained by cone-beam computed tomography and to map the periapical and inter-radicular regions of the mandibular bone. Material and Methods: In total, periapical bone regions of 6898 roots scanned by cone-beam computed tomography were evaluated retrospectively, and the results were recorded using Hounsfield units (HU). Results: The correlation between periapical HU values of adjacent mandibular teeth were strongly positive (P ˂ 0.01). The anterior region of the mandible yielded highest mean HU value (633.55). The mean periapical HU value of the premolar region (470.58) was higher than that was measured for molar region (374.58). The difference between furcation HU values of the first and second molars was unnoticeable. Conclusions: The results of this study have tried to evaluate the periapical regions of all mandibular teeth, which could ease to predict the bone radiodensity before implant surgery. Even though the Hounsfield units provide the average radio-bone density, a site-specific bone tissue evaluation of each case is essential for appropriate cone-beam computed tomography preoperative planning.

Effects of Crest Morphology on Lingual Concavity in Mandibular Molar Region: an Observational Study.

Objectives: The aim of this radiological study is to evaluate the lingual concavity dimensions and possible implant length in each posterior tooth region according to posterior crest type classification by using cone-beam computed tomography. Material and Methods: According to inclusion criteria, 836 molar teeth regions from 209 cone-beam computed tomography images were evaluated. Posterior crest type (concave, parallel, or convex), possible implant length, lingual concavity angle, width, and depth were recorded. Results: In each posterior tooth region, concave (U-type) crest was detected most frequently while convex (C-type) was the lowest. Possible implant length values were higher in second molar regions than first molars. Lingual concavity width and depth were decreasing from second molars to first molars for both sides. Additionally, lingual concavity angle showed higher values in second molar sites than first molars. In all molar teeth regions, lingual concavity width values were the highest in concave (U-type) crest type while they were the lowest in convex (C-type) crest type (P < 0.05). Lingual concavity angle values were recorded as the highest in concave (U-type) and the lowest in convex (C-type) crest type at the left first molar and right molars (P < 0.05). Conclusions: The lingual concavity dimensions and possible implant length may vary according to crest type and edentulous tooth region. Due to this effect, the surgeons should examine crest type clinically and radiologically. All parameters in the present study are decreasing while moving from anterior to posterior as well as from concave (U-type) to convex (C-type) morphologies.

Evaluation of Cortical Thicknesses and Bone Density Values of Mandibular Canal Borders and Coronal Site of Alveolar Crest.

Objectives: The objectives of this retrospective study are to measure the amount of the alveolar crest cortication and cortication around the mandibular canal, and to evaluate bone density values of alveolar crest, cortication around mandibular canal, and possible implant placement area for edentulous sites. Material and Methods: Six hundred forty-two cone-beam computed tomography scans from 642 subjects were evaluated in four centers. Cortical thicknesses of alveolar crest and mandibular canal cortical borders (buccal, lingual, apical, and coronal) in each mandibular posterior teeth region were measured. Bone density of alveolar crest and mandibular canal cortical borders (buccal, lingual, apical, and coronal) in each mandibular posterior teeth region were recorded. The correlations between numeric variables were investigated using Pearson's correlation test. Results: The largest cortical border of the canal was measured 1.1 (SD 0.71) mm at the left second molar area and in coronal side of the mandibular canal (MC). Left and right first premolar regions showed higher bone density values compared to the other sites in all bone density values evaluations. The buccal side of the canal at the right first premolar region showed the highest bone density values (832.32 [SD 350.01]) while the coronal side of the canal at the left second molar region showed the lowest (508.75 [SD 225.47]). The bone density of possible implant placement area at the both left (692.25 [SD 238.25]) and right (604.43 [SD 240.92]) edentulous first premolar showed the highest values. Positive correlations between the bone density values of alveolar crest and the coronal side of MC were found in molar and left second premolar regions (P < 0.05). Conclusions: Results may provide information about the amount of cortication and bone densities tooth by tooth for posterior mandible to surgeons for planning the treatment precisely.

Iliac crest flap for mandibular reconstruction after advanced stage mandibular ameloblastoma resection.

Ablative surgeries for neoplastic processes of the oral cavity, traumas, infections/inflammations, osteoradionecrosis, and congenital deformities are the most common causes of large mandibular defects. Ameloblastoma is a locally aggressive tumor that, if not treated, can gain an enormous size and cause severe facial disfigurement and functional impairment. Although the smaller lesions of ameloblastoma in the mandible are treated by conservative approaches such as marsupialization, enucleation, and curettage combined with liquid nitrogen spray cryosurgery, larger lesions require radical surgical ablation procedures resulting in large tissue defects. A large mandibular defect has deleterious effects on a person's life, with a significant loss in the quality of life unless it is reconstructed successfully. The aim of present case series report is to show the results of the multidisciplinary treatment of patients with advanced stage ameloblastoma, including tumor resection, simultaneous reconstruction with iliac crest flap, followed by placement of endosseous dental implants, and finally the prosthodontic rehabilitation.

Possible Association between the Quantity of Peri-implant Crevicular Fluid, Clinical Indices, and the Dimensions of Endosseous Implants.

Objectives: The objectives of this clinical observational study are to measure peri-implant crevicular fluid volume based on dental implant diameter and length, and to evaluate the possible relationship between peri-implant crevicular fluid/gingival crevicular fluid volumes and clinical periodontal indices. Material and Methods: The information about length and diameter of dental implants was noted. Clinical indices (probing depth, plaque index, gingival bleeding time index, and gingival index) were recorded. Peri-implant crevicular fluid (PICF)/gingival crevicular fluid (GCF) volumes were measured from 4 sites (mesial, buccal, distal, and lingual/palatal) of each dental implant including its one or more equivalent natural tooth/teeth. Results: One-hundred-sixty-one loaded dental implants and 221 natural teeth of 101 patients were evaluated. The length of dental implant had no effect on PICF volume (P > 0.05). However, PICF volumes of narrow (< 3.5 mm) and wide (> 4.5 mm) diameter implants were higher than standard diameter implants (≥ 3.5 mm, and ≤ 4.5 mm) (P < 0.05). PICF and GCF volumes of areas with peri-implant/periodontal diseases were significantly higher than healthy areas (P < 0.05). PICF and GCF volumes showed positive correlations with clinical indices (P < 0.05). Conclusions: In accordance with the results of the present study, the implant diameter, not the implant length, affects peri-implant crevicular fluid volume.

The Radiological Evaluation of Mandibular Canal Related Variables in Mandibular Third Molar Region: a Retrospective Multicenter Study.

Objectives: The aim of this retrospective study was to investigate anatomical structure of mandibular canal and the factors those increase the possibility of inferior alveolar nerve damage in mandibular third molar region of Turkish population. Material and Methods: Overall 320 participants with 436 mandibular third molars were included from four different study centers. Following variables were measured: type and depth of third molar impaction, position of mandibular canal in relation to third molars, morphology of mandibular canal, cortication status of mandibular canal, possible contact between the third molars and mandibular canal, thickness and density of superior, buccal, and lingual mandibular canal wall, bucco-lingual and apico-coronal mandibular canal diameters on cone-beam computed tomography scans. Results: Lingual mandibular canal wall density and thickness were decreased significantly as the impaction depth of mandibular third molar was increased (P = 0.045, P = 0.001 respectively). Highest buccal mandibular canal wall density and thickness were observed in lingual position of mandibular canal in relation to mandibular third molar (P = 0.021, P = 0.034 respectively). Mandibular canal with oval/round morphology had higher apico-coronal diameter in comparison to tear drop and dumbbell morphologies (P = 0.018). Additionally, mandibular canals with observed cortication border and no contact with mandibular third molar had denser and thicker lingual mandibular canal wall (P = 0.003, P = 0.001 respectively). Conclusions: Buccal and lingual mandibular canal wall density, thickness and mandibular canal diameter may be related with high-risk indicators of inferior alveolar nerve injury.