mandible

 Clinical identification of the inferior alveolar canal (IAC) is crucial before performing surgical interventions such as mandibular third molar extraction or jaw fixation to preserve the integrity of the IAC. This study evaluated the visibility of IAC borders using panoramic radiography (conventional and CBCT reformatted) and cross-sectional CBCT images.

 The conventional panoramic (CP) and CBCT images of 328 patients were evaluated, and the visibility of the IAC was assessed by three examiners across four equal 1 cm-wide regions, from anterior to posterior (Areas 1 to 4). For CBCT, reformatted panoramic (CRP) views were generated using curved multiplanar reformatting at the mandibular mid-root level within the software. Four cross-sectional images were obtained for each region. Visibility was rated as visible (score=1) or non-visible (score=0) across the three imaging modalities. Statistical significance was set at P value<0.05.

 Across all three radiographic modalities, the inferior border of the IAC was more consistently visible than the superior border. The highest visibility of the inferior border was observed in Area 4, with visibility rates of 92.1% for cross-sectional CBCT, 91.5% for CBCT-reformatted panoramic, and 92.4% for CP. The lowest visibility was found at the superior border in Area 2, with visibility rates of 86.9% for cross-sectional CBCT, 80.2% for CBCT-reformatted panoramic, and 67.4% for CP.

 Visualization of the IAC in the distal area of the mental foramen is more challenging than in other areas across all radiographic modalities. Given the superior visibility levels observed in CBCT images, especially for the superior border in Areas 1, 2, and 3, CBCT is recommended over CP radiography.

Peripheral (extra-osseous) dentinogenic ghost cell tumors are an extremely rare type of odontogenic lesions. They show a slight male predilection and most commonly occur in the anterior gingiva of the mandible. The peak incidence is above 50 years of age, and unlike the intraosseous type, they are generally nonaggressive. Diagnosing intra-oral lesions can be challenging, and less common lesions are often overlooked. Case: This report aimed to describe a peripheral dentinogenic ghost cell tumor as a painless, pedunculated mass in a 62-year-old male.

Understanding this unusual entity can facilitate a proper diagnosis and enhance our comprehension of its biological behavior.

The present study aimed to assess the frequency, Lingual Concavity Angle (LCA) and the different types of lingual concavity in the posterior mandible. In this study Cone Beam Computerized Tomography (CBCT) images of 670 mandibular bodies in the molar areas were evaluated. Cross-sectional images of the mandible were reconstructed at furcation points of first molar area. The LCA was measured. The subjects with LCA smaller than 85° were considered as concave. Then, the concave subjects were classified into three groups: angle less than 40°, angle between 40-60°, and angle between 60-85° were designated as extremely deep, deep, and mild deep, respectively. The most common type of lingual concavity was mild deep, followed by deep, and extremely deep. There was a significant positive correlation between the LCA and the age of participants (p<0.001). There was also significant relationship between the age of participants and the type of lingual concavity (p<0.001). The subjects in mild deep group were significantly older than deep group (p=0.032). Also, the non-concave subjects were significantly older than deep and mild deep subjects. (p=0.001 and 0.040, respectively). The LCA was significantly higher in males than females (p=0.020). The LCA was significantly larger on the left side (p<0.001).  The presence of deep lingual concavity was common (95%.). Also, mandibular lingual concavity types were found to vary by age, and laterality. Moreover, the LCA was significantly different according to patient age, sex, and laterality.

The duration of orthodontic treatment is often a significant deterrent for patients when considering conventional mechanics, which can be time-consuming. Photobiomodulation (PBM) utilizes visible red to near-infrared wavelengths of light frequencies to expedite orthodontic treatment time.
To investigate the effect of three Light Emitting Diode (LED) frequencies and their heat generation on soft tissues in accelerating tooth movement through Finite Element Method (FEM) study.
In this FEM study, a three-dimensional FEM model of the skull of a male patient with mild to moderate crowding in the maxilla, and mandible. The dentitions were scanned using a Computed Tomography (CT). A static force of 70 gm on the anterior region of the maxilla and mandible was applied from the labial sides, and a second static analysis was carried out by using both a 70 gm of force and thermal load with three different frequencies of 740, 850, and 940 nm on the 1st and 3rd quadrants. The effect of LED application and heat generation was assessed on soft tissues in bringing faster orthodontic tooth movement.
Increased tooth movement with combined loading case in the 1st and 3rd quadrants when compared with the 2nd and 4th quadrants. The temperature distribution was higher at 940 nm followed by 740 & 850 nm of frequency. 
Faster movements were observed in the combined loading case in the 1st and 3rd quadrants compared to static loading in other quadrants. Heat generation was higher with 940 nm frequency followed by 740 and 850 nm.

Successful endodontic treatment depends on completely clearing, shaping, and filling the prepared canals. Knowledge of the common and aberrant varying pulp anatomies is essential for suitable root canal treatment. Since, this anatomy is complex and varies morphologically in different populations. This study aims to determine the number of roots, canals, and evaluation of mandibular premolars canals using cone -beam computed tomography (CBCT) images in one of Iran's northern provinces (Golestan).

CBCT axial, coronal, and sagittal slices of two hundred and twelve mandibular premolars were analyzed to determine the number of roots and canals based on Vertucci type. The images were analyzed in a one-millimeter slice in mesiodistal and buccolingual dimensions based on gender. The data were analyzed using the Chi-score test to compare the components if the defaults were not established. A significance level of 0.05 was considered.

Of the two hundred twelve teeth evaluated, 130 (61.3%) were first premolars, and 82 (38.6%) were second premolars. Most first premolars (78.5%) and almost all second premolars (97.6%) had one root. Morphological types of root canals were identified based on Vertucci’s classification types I, II, III, IV, V, or VIII, and type I was the most frequent. There were no significant associations between number of roots and sex (P>0.05).

Mandibular premolars mostly had one root and type I Vertucci morphology. The frequency of two-canal premolars was higher in the male population. Although the abundance of two or three roots with different morphologies was also observed, the possibility of the presence of an additional root canal should be considered

Cemento-osseous dysplasia (COD) is classified, by the World Health Organization as a benign fibro-osseous lesion related to the tooth and periapical area of the jaws and is considered as a benign reactive process appearing from the apical periodontium in close relation with the apices of teeth. Usually, it is asymptomatic, discovered accidentally, and affecting particularly middle-aged African women. There are four subtypes distinguished of the lesion: periapical (PCOD), focal (FCOD), florid (FLCOD) and familial florid cemento-osseous dysplasia (FFLCOD). Pseudocysts found in the jaws go by various names, including solitary bone cyst, traumatic bone cyst, or simple bone cyst (SBC). These two pathologies have been reported separately; however, their co-occurrence remains rare and the first case of FLCOD with co-occurrence of SBC was reported by Melrose et al. in 1976 and later a few cases been reported in the literature. The aim of this report is to describe a case of a 46-year-old oriental female diagnosed with FLCOD with co-occurrence of SBC. Under local analgesia, a surgical exploration of the cyst was performed. In addition, a biopsy with a trephine was done in the region of missing right first mandibular molar. Based on the patient clinical, radiographic, and histological findings, a diagnosis of FLCOD was made in co-occurrence with a mandibular SBC. An examination of another female family member unveils a distinctive case, and the familial factor has been ruled out. No further treatment was planned and only follow-up was suggested.

Odontogenic tumors are lesions with unique microscopic patterns and clinical behavior. They are divided into three groups: epithelial, mesenchymal, and mixed. These neoplasms have several unique microscopic patterns; however, limited information exists on their infrequent features. This study aimed to enquire into the infrequent histopathologic features of odontogenic neoplasms in an oral pathology referral center in Iran.

 The archives of oral pathology department, Shahid Beheshti University of Medical Sciences, were investigated retrospectively over a 30-year period. The files with a diagnosis of odontogenic tumors were selected. All microscopic slides were re-evaluated, and cases with infrequent features were extracted. Finally, demographic data were extracted and analyzed for possible correlations with pathologic features.

 Over 30 years, 503 odontogenic tumors were diagnosed, of which 30 (5.96%) showed infrequent microscopic features. The mean age of patients was 33.7, ranging from 15 to 69 years. Mandibular predilection (80%) was the most prominent feature, and the male-to-female ratio was 0.87. Approximately 80% of the lesions displayed painless swelling. In solid ameloblastoma, microscopic features included adenoid appearance, hyalinization, keratin pearls, dyskeratosis, and hemangiomatous appearance. Papillary patterns, pure granular cells, clear cells, hypercellular whorls, and ghost cells were also observed, while ameloblastic carcinomas most commonly showed mucous cells, keratin pearls, and sheets of spindle cells.

 Although odontogenic tumors are mostly a homogeneous group of tumors, they sometimes show diversity in several features, many of which indicate the multipotentiality of the odontogenic epithelium. In this study, although all the criteria of adenoid tumors were not observed, five samples showed some features of adenoid ameloblastoma.

 The present study investigated the skeletal and dental effect in class II division I growing patients due to mandibular deficiency treated with the hybrid aesthetic functional (HAF) appliance.

 A sample of 16 growing patients (5 boys and 11 girls; mean age: 9.50 years, standard deviation: 1.15) with class II division I malocclusion were treated using the HAF appliance for an average period of 10±3 months. For each patient, a cephalometric radiograph was taken before and after treatment, and digital analysis was applied using the WebCeph program. The statistical analysis was performed to evaluate dental and skeletal changes associated with the HAF appliance and determine if there were any statistically significant variations in anatomical measurements between the start and completion of the treatment.

 The data showed a significant increase in SNB angle (P=0.002), leading to a significant decrease in ANB angle (P=0.001). The mandibular length significantly increased (P=0.008), the lower incisors were flared significantly (P=0.028), and the lower molars were extruded significantly (P≤0.001). Also, this study revealed a significant decrease in Wits appraisal (P≤0.001), overjet (P≤0.001), and overbite (P=0.041). Additionally, a significant increase in lower anterior facial height (P≤0.001), total facial height (P=0.001), and posterior facial height (P=0.037) were observed.

 The HAF appliance showed that it could be used to correct class II division 1 skeletal discrepancy by mandibular advancement. The HAF appliance increased all facial heights significantly.

Stereological methods to measure structural changes play an important role for diagnosing and evaluating the healing process of diseases in organs. Zoledronate, used to treat bone diseases, causes osteonecrosis of the jaw following mechanical injuries and is a challenge in clinical settings. This experiment aimed to investigate histopathological changes in subcomponents of mandibular bone trabeculae after mechanical trauma in zoledronate-induced rats by using stereological methods.

Fifty female rats (220-270g) were randomly assigned to experimental and control groups. 25 rats in the experimental group were injected 0.06 mg/kg zoledronic acid (ZA) intraperitoneally, and 25 animals in the control group were injected saline. Injection was performed once a week for 8 weeks, and then dental extraction was done for each animal. Four weeks after extraction, the rats were euthanized and the right hemimandibles were removed, decalcified, cut into serial sections at 5 microns, stained with hematoxylin-eosin, and subjected to stereological analyses. Data were analyzed by using SPSS version 26.

The volume of bone matrix and empty lacunae was significantly higher in experimental rats than that in controls four weeks after extraction (P < 0.05). Reduction of the volume of osteocytes, osteoblasts, osteoclasts, and Howship’s lacunae in experimental group was observed when compared with the controls (P < 0.05).

The stereological methods in the present study provided a standardized and reproducible methodology for quantitative analysis of histopathological changes and can be used as a basis for future studies investigating preventive or therapeutic strategies for Medication-Related Osteonecrosis of the Jaw (MRONJ) that are evidence-based and associated with accurate and valid data.

Tooth impaction refers to the failure of a tooth to properly emerge in its expected position within a given timeframe. Several local factors influence the occurrence of tooth impaction, one of which is the specific morphometric characteristics of the mandible. The objective of this study is to examine the association between these factors and the type of impaction observed in the mandibular third molar.

In this Cross-sectional study, 186 impacted mandibular third molar from patients with 20 to 30 years of age were evaluated. The mandibular third molars were categorized according to Pell and Gregory classification into A (third molar is at the same level as the occlusal plane of the second molar), B (third molar is between the occlusal plane and Cementoenamel junction (CEJ) of the second molar) and C (third molar is below the CEJ of the second molar) groups. The Chi-square test was used for statistical analysis of the data. The relation between gonial angle and ramus height with third molar impaction type was assessed using a Pearson correlation test.

The mean±SD for gonial angle in A, B and C groups were 121.05±6.33, 120.24±5.43 and 119.67±5.17 respectively. The mean±SD for ramus height in A, B and C groups were 58.51±5.01, 57.63±5.14 and 57.38±4.51 respectively. There was no significant relation between mandibular third molar impaction type and gonial angle and ramus height (P>0.05).

There was no significant relationship between the gonial angle and ramus height and the type of mandibular third molar tooth impaction according to Pell & Gregory classification as well as eruption and impacted state of mandibular third molar. The results of this study can be used by dentists to assess the difficulty of mandibular third molar extraction prior to their surgeries.

 Having knowledge of root canal morphology is a crucial requirement for effective treatment. Taking into account the impact of factors such as age, gender, and race on the diversity of root canals in teeth, this study aimed to investigate the prevalence of middle mesial (mid-mesial) canals and isthmus in mandibular first and second molars in a specific subpopulation of Tabriz patients. Cone-beam computed tomography (CBCT) was used for this investigation.

 CBCT radiographs of 215 patients were examined to determine the presence of the mid-mesial canal and isthmus in mandibular first and second molars without endodontic treatment based on gender. All samples were obtained from the Faculty of Dentistry, Tabriz University of Medical Sciences, in 2019. The obtained results were analyzed using SPSS version 16, employing a chi-square test (P < 0.05).

 On the left mandibular side, twenty-eight samples (13%) exhibited a mid-mesial canal in both the first and second molars. On the right side, these values were 29 (13.5%) and 47 (21.9%) for the first and second molars, respectively. Regarding the frequencies of isthmus in mandibular first and second molars, the values were 2 (0.9%) and 18 (8.4%) on the right side and 5 (2.3%) and 21 (9.8%) on the left side, respectively (P-values = 0.147, P = 0.938, P = 0.193, and P = 0.713 in left first, left second, right first, and right second mandibular molars, respectively, which were insignificant).

 This study revealed a low prevalence of mandibular first and second molars with mid-mesial canal and isthmus. The left and right sides and gender did not influence this prevalence.

Neurofibroma is a benign tumor derived from the peripheral nerve. Most of these can be multifocal as a component of neurofibromatosis or present as a solitary tumor. Although the solitary neurofibroma is not an uncommon lesion, its intraosseous occurrence is rare, and less than 50 cases have been reported. We report a rare case of central neurofibroma, arising in the mandibular bone of 57-year-old edentulous female patient on the left side. Hemi mandibulectomy was performed and reconstructed with a reconstruction plate without any bone graft. Microscopic evaluation showed neoplastic tissue with haphazardly arranged and interlacing fascicular patterns composed of point-ended spindle-shaped tumoral cells. Immunohistochemical examination of the tumor showed positive staining for S-100 protein antibodies.

Complex odontomas are commonly found in the anterior maxilla and mandible, and are typically asymptomatic unless they cause tooth displacement or other complications. Management of odontomas depends on the size and location of the lesion, and may include surgical excision and bone grafting.

This case report presents a rare case of complex odontoma in a 20-year-old female patient complaining of a maxillary malposed tooth along with a swelling for the past 5 years. The patient underwent excision of the lesion along with extraction of the affected tooth and autogenous bone grafting of the defect site. Histopathological analysis confirmed the provisional diagnosis of odontoma.

This case report highlights the importance of proper diagnosis and management of odontomas to prevent potential complications.

Knowledge about the anatomic variations of the root canal system and their prevalence is necessary for clinicians to ideally clean the root canal system. The anatomic complexity of the root canal system is one of the reasons for its inadequate debridement, resulting in residual microorganisms and root canal treatment failure. The present study aimed to evaluate the prevalence of middle mesial root canals in mandibular molars in an Iranian population.

The samples in the present descriptive/cross‑sectional study consisted of mandibular first and second molars (n = 100, with 50 first and 50 s molars). A convenient sampling method was used to collect samples. The teeth were mounted in gypsum and scanned using a micro‑computed tomography unit. The images were reconstructed with software, and the relevant checklist was completed by the observers. The data were analyzed with SPSS v26 using the Chi‑squared test at a significance level of P < 0.05.

The prevalence of the middle mesial root canal in the present study was 36% for mandibular first molars and 22% for mandibular second molars, with an overall prevalence of 29%. The prevalence of the middle mesial root canal was not significantly different between the first and second mandibular molars (P = 0.12). The mean distance between the mesiobuccal and mesiolingual root canal orifices in the teeth with a middle mesial root canal was significantly higher than in those without the middle mesial root canal (P < 0.001). In addition, there was no significant difference in the prevalence of the middle mesial root canal between the teeth with and without the second distal root canal (P = 0.89).

The prevalence of the middle mesial root canal in the studied population was 29%, which is significant clinically. In addition, the mean distance between the mesiobuccal and mesiolingual root canal orifices in teeth with a middle mesial root canal was higher than that in teeth without this root canal.

The aim of this retrospective study was to assess the dimensions of the mandibular molar socket for immediate implant placement, using cone-beam computed tomography (CBCT) imaging.

The CBCT images of 81 patients were selected based on the inclusion and exclusion criteria. In the OnDemand software, measurements were assessed by virtually positioning a regular Straumann implant (4.8 mm) in the regions of the first and second mandibular molars. The socket morphology, the buccolingual width of cancellous bone, the gap between the implant and the socket wall, the length of the root, the cross-sectional morphology of the mandible, and the height and thickness of the inter-radicular septum were all determined. The variables were compared using either the Student’s t-test or the Mann-Whitney U test.

Among the cross-sectional morphologies of the mandible, the undercut type (U) was found to be the most prevalent. The mean distance of the implant from the inferior alveolar nerve (IAN) was found to be 6.22 mm for the first molars and 5.17 mm for the second molars. Moreover, the mean horizontal distances from the implant to the mesial and distal socket walls were 2.01 and 2.30 mm for the first molars and 2.14 and 2.59 mm for the second molars, respectively. The width of the interradicular septum across various sections was found to have a significant correlation with the position of the tooth (P<0.05).

The majority of the samples exhibited the undercut (U type) morphology of the mandible. The interradicular septum in the second molar tooth was found to be insufficient. Overall, the assessment of pre-extraction CBCT scans and the virtual positioning of implants can be beneficial for surgical treatment planning. This approach can also aid in minimizing potential complications.

Hypodontia is the most common dental developmental disorder. Several underlying mechanisms have been proposed to be involved in its pathogenesis. Occurrence of hypodontia as an isolated trait due to genetic mutations has also been reported. Hypodontia most commonly involves the mandibular premolars, maxillary lateral incisors and second premolars. However, hypodontia of permanent second molars is a rare occurrence. To the best of the author’s knowledge, only two studies on orthodontic patients have reported hypodontia of permanent second molars in Iran.This case report describes non-syndromic bilateral missing of permanent mandibular second molars in a 10-year-old child. Clinical examination revealed no systemic underlying condition, and no clinical evidence of any syndrome, or hereditary or familial pattern. Due to the potential impact of hypodontia on the function of dentition, prompt management of hypodontia is imperative. Furthermore, due to the possible mutations associated with hypodontia, additional screening for cancer susceptibility may be recommended.

Metastatic lesions of the jaws are a diagnostic challenge because of their scarcity and uncharacteristic clinical-radiographic features. Carcinoma of unknown primary origin (CUP) is characterized by the existence of metastatic disease with no recognized primary neoplasm after a comprehensive work-up. CUP shows a poor prognosis with limited treatment choices. This paper presents a 64-year-old male with a chief complaint of paresthesia of the chin and lower lip. Panoramic radiography showed an ill-defined radiolucency in the left mandibular molar area and the residue of the first molar root. Microscopic examination demonstrated features of mucin-producing adenocarcinoma and was not similar to common neoplasms of the jaw. The whole-body scan revealed multiple osseous uptakes. CDX2 was diffusely positive. However, in the end, the origin of the primary tumor was not determined. Considering the aforementioned data, the diagnosis of metastatic adenocarcinoma with unknown primary origin was made. CUP of the oral cavity is an extremely rare event. The possibility of metastasis should be raised in a patient who complains of paresthesia. Awareness of the clinical and histopathologic features of these malignancies is crucial for clinicians and pathologists to have a proper diagnosis.

 The aim of this narrative literature review was clinical indications as well as common complications of the most common treatment options for oral rehabilitation of the upper jaw. The paper also introduced a novel decision-making tool for guiding the selection of the most appropriate treatment for oral rehabilitation based on patients’ residual bone height, width, and quality.

 This study is a review article based on PubMed and Scopus that was done by reviewing articles from 2000 to 2022. Treatment choices for edentulous maxillae with the insufficient bone for implant placement comprise two broad classifications: bone defect compensation by bone augmentation techniques and modified implant designs for specific situations to utilize the remaining bone. The following factors have to be taken into consideration: the residual bony anatomy, remaining bone volume and quality, skeletal maxillomandibular relationship, scientific evidence, the experience of the clinicians, and, the patients’ increasing demands and expectations.

 Grafting techniques are often demanding for both patients and surgeons. Likewise, they are associated with a prolonged treatment time, increased financial cost, and higher complication risks, especially in medically compromised patients. Several non-grafting alternative options have been reported such as zygomatic implants (ZIs), short implants, tilted implants, and the like.

 Oral rehabilitation in the upper jaw should follow a comprehensive assessment and examination of the patient’s quality and dimensions of residual bone. The clinical decision between grafting versus non-grafting options is associated with several factors.

Sagittal split ramus osteotomy is one of the most efficient steotomy techniques for orthognathic surgery.  This technical note presents a new technique of mandibular osteotomy to prevent bony interferences  with simultaneous maxillary impctions. As well as increase in bone contact for great mandibular  advancements which results in better bone healing. furthermore, Fixation of bony segments in  this area is far from third molar alveolar socket if extraction is done and is not involved in the process.