Relationship between Impacted Mandibular Third Molars and the Mandibular Canal on CBCT Scans.

This study aimed to assess the relationship of impacted mandibular third molars with the mandibular canal on cone beam computed tomography (CBCT) scans. This cross-sectional study was conducted on CBCT scans of 137 patients with 204 impacted mandibular third molars. The relation of age, gender, class of impaction, anatomical position of canal relative to tooth (buccal, lingual, inferior, inter-radicular), tooth angulation (mesioangular, vertical, distoangular, horizontal), relationship of tooth with the mandibular canal (no contact, in contact, relation), relationship of tooth with the mandibular cortex, anatomical site of contact of tooth with the mandibular cortex (buccal, lingual, inferior), and the impression of canal (grooving, no effect) on impacted teeth were evaluated. Data were analyzed using one-way ANOVA, Chi-square test and Fisher's exact test. Class B of impaction (78.9%), inferior position of canal relative to the impacted tooth (53.9%) and mesioangular angulation (53.4%) had the highest frequency, respectively. The relationship of tooth with the mandibular canal was "relation" in most cases (53.4%) followed by no contact (26.9%) and in contact (19.6%). Significant associations were noted between depth of impaction (P < 0.001), tooth angulation (P = 0.024), anatomical position of canal relative to tooth (P < 0.001), relationship of tooth with the mandibular cortex (P = 0.032) and anatomical site of contact of tooth with the mandibular cortex (P = 0.013) with the impacted tooth-mandibular canal relationship. CBCT provides accurate information about the relationship of impacted third molars with the mandibular canal and can decrease the risk of traumatization of inferior alveolar nerve (IAN) during their surgical extraction.

Assessment of bony changes in temporomandibular joint in patients using cone beam computed tomography - a cross sectional study.

BACKGROUND AND AIM: The aim of this study is to evaluate the changes in the temporomandibular joint (TMJ) in patients with temporomandibular disorder (TMD) and the relationship between age, sex, and types of TMJ change using Cone Beam Computed Tomography (CBCT). METHODS AND MATERIAL: CBCT records of 200 patients (123 women and 67 men) were retrieved and assessed. Right and left TMJs were evaluated separately, resulting in a total of 400 TMJs. The images were analyzed using On demand 3D Application The radiographic findings were classified as erosion, proliferative changes mainly, including flattening and osteophytes of the condyle, sclerosis, Ely cyst, hypoplasia and hyperplasia of the condyles, ankylosis, and joint cavity. Data analysis was performed using descriptive statistics, paired T-tests, and repeated measure ANOVA (Analysis of Variance) in SPSS Software. RESULTS: The most prevalent types of condylar bony changes observed was osteophyte (63.5%) followed by flattening of the articular surface (42%), erosion (40%), ankylosis (10%) and sclerosis (10%). 7.5% of joints showed hyperplastic condyles but only 2% showed hypoplasia. The least prevalent change observed was Ely Cyst (1%). Osteophyte was the most prevalent change observed in all age groups and both sexes except for men aged 31 ~ 50, where flattening was more frequent. A statistically significant difference was found between sex and prevalence of erosion in the age group of 10 ~ 30 (P = 0.001); as well as between sex and condylar hyperplasia in the same age group. CONCLUSION: Based on the findings of this research, the prevalence of bony changes of TMJ from highest to lowest is as follows: osteophyte, flattening of the articular surface, erosion, ankylosis, sclerosis, hyperplastic condyles, hypoplastic condyles and Ely Cyst. CBCT is an accurate 3 dimensional imaging modality for assessment of TMJ bony structures.

Assessment of Inferior Alveolar Nerve Position at the Region of First and Second Mandibular Molars in Dentate and Edentulous Sites Using Cone Beam Computed Tomography: A Cross-Sectional Study.

Determining the position of the Inferior alveolar nerve (IAN) is an important factor prior to any surgical procedure in the mandible such as dental implant insertion and surgical tooth extraction. The aim of this study was to compare the position of IAN in partially edentulous patients in the lower first and second molars in both missing and dentate sides. A total of 200 CBCT scans were chosen randomly and examined. On cross-sectional views, the distance between lower border of IAN canal and upper border of inferior cortex of mandible (IC) were measured at the site of dentate and edentulous mandibular first and second molar. Paired-sample t-test was used to analyze and compare measurements on right and left sides. A total of 100 males and 100 females with mean age of 46.05 ± 12.33 years were included. The IC distance measured in four pairs were as follows: Pair one: 80 cases with right missing 6 (mean ± SD = 3.73 ± 1.29 mm) and left present 6 (mean ± SD = 3.42 ± 1.20 mm), Pair two: 20 cases with right present 6 (mean = 3.20 ± 1.48 mm) and left missing 6 (mean ± SD = 3.96 ± 1.62 mm), Pair three: 54 cases of right missing 7 (mean ± SD = 3.83 ± 1.74 mm) and left present 7 (mean ± SD = 3.62 ± 1.74 mm), and Pair four: 46 case of right present 7 (mean ± SD = 3.49 ± 1.56 mm) and left missing 7 (mean ± SD = 3.84 ± 1.42). The IAN was statistically more distant from inferior cortex of mandible in the edentulous parts compared with the non-edentulous part (P < 0.05). The IAN was positioned farther from the inferior cortex of mandible in edentulous sites compared with dentate parts. Cautious consideration is essential in any surgical procedure and dental implant operations to prevent IAN injury.

Influential Factors in Buccal and Lingual Plate Perforation around Dental Implants Using Cone-Beam Computed Tomography.

This study determined the influential factors in buccal and lingual plate perforation around dental implants using cone-beam computed tomography (CBCT). In this retrospective, cross-sectional study, CBCT scans of dental implants taken for purposes not related to this study from 2017 to 2018 were retrieved from the archives of a private dental clinic. Demographic information, implant site, length, diameter, shape, and angulation, buccal and lingual plate thickness, buccolingual diameter of bone, and presence of crestal bone resorption were all assessed on CBCT scans. Data were analyzed using chi-squared, Mann-Whitney, Kruskal-Wallis, and independent t-tests. Of 604 implants, 88 had caused bone perforation in 41 females (46.6%) and 47 males (53.4%) with a mean age of 54.97 ± 13.99 years; 83% of perforations were in the maxilla; 55.7% of implants causing perforation were cylindrical and 44.3% were conical. The mean length and diameter of implants was 11.78 ± 1.91 mm, and 4.49 ± 0.76 mm, respectively; 38.9% of perforations were in the buccal and 18.2% in the lingual plate, and 42% were in the apical region. Crestal bone loss was noted in 58% of perforation cases. The mean angular deviation of implants was 19.13 ± 12.41°. Implant length and diameter had a significant association with the occurrence of perforation in the mandible (P < 0.05). Perforations had a higher frequency in the posterior maxilla, and mainly in the apical region. The buccal plate was thin in the anterior maxilla, with minimum thickness in the apical region. Lingual plate perforation had the highest frequency in the mandible.

Evaluation of Maxillary Alveolar Ridge Morphology and Residual Bone for Implant Placement by Cone Beam Computed Tomography (CBCT).

The aim of this study was to assess the morphology and dimension of maxillary alveolar ridge at anterior and posterior regions using cone beam computed tomography (CBCT) prior to the placement of immediate implants. CBCT scans of 192 patients were evaluated. Measurements were taken at the cross sectional views in the maxillary central incisor, lateral incisor, canine incisor, first and second premolars and first and second molars regions. Alveolar ridge width and height, buccal plate thickness, buccal undercut, inter-root septum height, and root penetration to sinus floor were measured. Independent T-test was used for statistical analysis. The mean value of alveolar height in the maxillary incisors were higher than the posterior teeth with central incisors having the highest value of 19.23 ± 8.74 mm. At anterior maxilla, the lateral incisor with the mean value of 1.07 ± 0.64 mm exhibits the highest buccal undercut and the thinnest ridge width. At the site of posterior regions premolars had higher buccal undercut than molars. Canine with the mean value of 0.19 ± 0.31 mm thickness at the mid-alveolar of buccal plate, had the thinnest plate among other maxillary incisors. Sinus penetration and inter-root septum height were higher in premolar teeth than molars. The mean value of ridge width at all levels was significantly different between men and women, except at the level of crest in central incisor. CBCT evaluation presents accurate measurements for ridge assessment prior to immediate implant insertion. The recommended appropriate size of implant platform would be 5 mm in the incisor and almost 6 mm in premolar region.

The Anatomical Position and Size of Greater Palatine Foramen and Canal in an Iranian Sample Using Cone Beam Computed Tomography.

Detection of location of greater palatine foramen (GPF) and its anatomical variations are vital prior to posterior maxillary surgeries. The aim of this study is to determine the anatomical position and size of the greater palatine canal and GPF using cone beam computed tomography (CBCT) scan. To determine the anatomical foramen position, the posterior maxilla area was divided into five regions on the axial view (A to E from the mesial surface of the second molar to distal surface of third molar). The length of the canal was investigated on both coronal and sagittal views. Independent t-test was used to analyze the data. Among 80 females and 68 males, the anatomical position of the GPF was mainly located in region E on the left (55%) and the right (50%), and then, respectively, in region D and region C. The mean diameter of GPF was 4/48 mm on the left and 4/63 mm on the right side (P = 0/01). The average length of the canal on the coronal view was 29.46 mm on the left side and 29.75 mm on the right (P = 0.005). The average length of the canal on the sagittal view was 29.62 mm on the left and 30.02 mm on the right (P = 0.001). The anatomical position of the GPF was primarily located distal to the third maxillary molar. CBCT is a valuable diagnostic tool for evaluation of vital anatomic landmarks in the maxillofacial region prior to surgeries.

Quantitative Evaluation of Bone-Related Factors at the Implant Site by Cone-Beam Computed Tomography.

OBJECTIVES: Dental implant is a commonly used treatment modality for replacement of the missing teeth. The aim of the present study was to evaluate a number of bone-related factors at the implant site preoperatively by cone-beam computed tomography (CBCT). MATERIALS AND METHODS: A total of 400 implant sites were evaluated on CBCT images. The height, width, angle of residual ridge, thickness of cortical bone crest, and the ridge concavity were evaluated on cross sectional images at four regions: the anterior maxilla, anterior mandible, posterior maxilla, and posterior mandible. RESULTS: The highest thickness of cortical bone was observed in posterior mandible followed by anterior mandible, anterior maxilla, and posterior maxilla. In the mandible, the mean buccal concavity was higher in the anterior than in the posterior region (P = 0.0094). The measurements indicated that in both the maxilla (P = 0.0256) and mandible (P < 0.0001), the residual ridge width was lower in the anterior than in the posterior region; while the height of the residual ridge was higher in the anterior than in the posterior region in the mandible (P < 0.0001). In the maxilla, the remaining ridge angle in the anterior region was greater than that in the posterior region (P < 0.0001). CONCLUSION: Anatomical variations detected on CBCT results in personalized treatment planning considering best site and the best fixture in terms of size and position prior to implant fixture insertion.

A New Classification of Anterior Mandible Edentulous Ridge Based on Cone Beam Computed Tomography.

Purpose - Dental implants in the anterior mandible have become increasingly common due to popular prosthetic treatments. The aim of this study was to evaluate cone beam computed tomography (CBCT) images of mandibles from edentulous patients in need of anterior dental implants to present qualitative descriptions in the mental interforaminal region and to present a new classification. Material and Methods - A total of 180 (CBCT) scans of patients requiring implant installation in the anterior mandible for implant assisted overdenture treatment plan were evaluated regarding parameters such as ridge height, width, inclination, and undercuts. All assessments were performed on the cross-sectional images mesial to the mental foramen. Results - The most common ridge morphology was cylindrical (74.1%) followed by atrophic (19.4%) and undercut (6.4%). The prevalence of atrophic ridge was significantly higher in females and ridge with undercut was significantly more detected in males (P < 0.05). D1 and D2 bone types was detected higher in males than in females (P < 0.05). Conclusion - Cylindrical morphology was the most prevalent features of anterior mandible of edentulous patients. A CBCT scan is a useful diagnostic tool providing important information about anatomical structures and morphological variations in the sites of interest.

Diagnostic Biomarkers in Oral Verrucous Carcinoma: A Systematic Review.

Oral verrucous carcinoma (OVC), a low-grade variant of oral squamous cell carcinoma (OSCC), is most frequently seen in the oral cavity. No clear etiology has been found for this lesion, but human papilloma virus, chewing betel nuts, and ultraviolet radiation are suggested as probable causes. Differential diagnosis of OVC is challenging for oral pathologists. The aim of this study was to review the molecular-based approaches for differential diagnosis of OVC. An electronic search was conducted in Medline and Scopus from January 2004 to July 2015 limited to English language publications. Published papers on verrucous carcinoma (VC) were found according to the inclusion and exclusion criteria and analyzed qualitatively. Data extraction were performed according to PRISMA statement. A total of 423 articles were reviewed; out of which, 26 articles completely fulfilled the inclusion criteria. Most of the included studies investigated proliferative and apoptotic biomarkers such as p53 and Ki67. No definite conclusion was drawn for cytoskeletal biomarkers due to variability of factors and lack of significant expression. However, it seems that cytokeratin10 (CK 10) can be useful for differentiation of OVC and benign squamous lesions. Among cell surface and extracellular matrix biomarkers tissue biomarkers, matrix metalloproteinase (MMP)-2, -9, CD31 and CD68 seem to be useful for differentiation of OVC and OSCC and glucose transporter-1 (GLUT-1) can help in differentiation of OVC from oral epithelial dysplasia. Differences among OVC, OSCC and normal epithelium in expression profiles of the investigated biomarkers help in their differential diagnosis; although, clinicohistopathological similarities among verrucous hyperplasia, noninvasive OVC and invasive well-differentiated OSCC make the diagnosis difficult. Further studies are required to better differentiate these oral lesions.

Smart scaffolds in bone tissue engineering: A systematic review of literature.

AIM: To improve osteogenic differentiation and attachment of cells. METHODS: An electronic search was conducted in PubMed from January 2004 to December 2013. Studies which performed smart modifications on conventional bone scaffold materials were included. Scaffolds with controlled release or encapsulation of bioactive molecules were not included. Experiments which did not investigate response of cells toward the scaffold (cell attachment, proliferation or osteoblastic differentiation) were excluded. RESULTS: Among 1458 studies, 38 met the inclusion and exclusion criteria. The main scaffold varied extensively among the included studies. Smart modifications included addition of growth factors (group I-11 studies), extracellular matrix-like molecules (group II-13 studies) and nanoparticles (nano-HA) (group III-17 studies). In all groups, surface coating was the most commonly applied approach for smart modification of scaffolds. In group I, bone morphogenetic proteins were mainly used as growth factor stabilized on polycaprolactone (PCL). In group II, collagen 1 in combination with PCL, hydroxyapatite (HA) and tricalcium phosphate were the most frequent scaffolds used. In the third group, nano-HA with PCL and chitosan were used the most. As variable methods were used, a thorough and comprehensible compare between the results and approaches was unattainable. CONCLUSION: Regarding the variability in methodology of these in vitro studies it was demonstrated that smart modification of scaffolds can improve tissue properties.

Effect of low level laser therapy on proliferation and differentiation of the cells contributing in bone regeneration.

INTRODUCTION: Low level laser therapy (LLLT) also known as photobiomodulation, is a treatment that uses low-level lasers or light-emitting diodes (LEDs) to change cellular function and is a clinically well accepted tool in regenerative medicine and dentistry. Considering the variety of laser, exposure, cells and study types, the exact effects of low level laser therapy seems to be unclear. The aim of this study was to review the data published in the field of the effects of low level laser therapy on proliferation and differentiation of the cells contributing in bone regeneration. METHODS: To access relevant articles, an electronic search in PubMed was conducted from 2001 to April 2014. English language published papers on low level laser therapy were found using the selected keywords .The full texts of potentially suitable articles were obtained for final assessment according to the exclusion and inclusion criteria. RESULTS: 240 articles were found from 2001 to April 2014. Following the initial screening of titles and abstracts as well as the final screening of full texts, 22 articles completely fulfilled the inclusion criteria of this study. Wavelength used in LLLT irradiation varied between 600 to 1000 nm with an energy density of 0.04-60J/cm(2) . Although almost all studies agreed on getting positive effects from LLLT, some had opposing results. CONCLUSION: Low level laser with low-energy density range appears to exert a biostimulatory effect on bone tissue, enhance osteoblastic proliferation and differentiation on cell lines used in in vitro studies. Despite the fact that many researches have been recently done on the effects of LLLT on different cell lines, without knowing the precise mechanism and effects, we are not able to offer a clinical treatment protocol. This paper is a beginning to help further progress and extend practical use of LLLT in future.