Associations between the 3D position of the mental foramen with sagittal skeletal relationships (classes I, II, and III) and vertical facial growth patterns (normal, long, and short faces) in different ages and sexes: a retrospective cohort study of 360 CBCTs.

BACKGROUND: The 3D position of the mental foramen (MF) is of significant clinical value in dental implantology and mandibular surgeries or in local anesthesia. Despite its importance, it is not clearly known how the position of MF can alter in different individuals, since the literature on the associations between the MF position with vertical growth patterns is non-existent and those on links between the MF position and skeletal malocclusions are scarce. Therefore, we aimed to investigate these, for the first time, on cone-beam computed tomographies (CBCTs). METHODS: Archival CBCTs of 9 sub-groups (i.e., 3 skeletal Classes I, II, and III × 3 vertical growth patterns 'long face, short face, normal face') were collected by evaluating patients' SNA, SNB, ANB, facial angle, lower facial height, and FMA (n = 9 × 40 = 360). Included cases were older than 17 years and without any history of orthodontic/orthognathic treatments (243 women, 117 men, mean age: 22.28 ± 2.80 years). Perpendicular distances between the MF and 3 fixed bony structures (the mandibular symphysis [S/width], the mandibular ramus [R/length], and the mandibular lower cortex [C/height]) were measured on different sectional planes on both hemimandibles. Left- and right-side measurements were combined. Data were analyzed using the 3-way ANCOVA, Bonferroni, one-way ANOVA, Tamhane, Pearson, and t-test (α = 0.05). RESULTS: Width was the smallest in Class II and greatest in Class III cases (all P values < 0.000001, Bonferroni). It was the shortest in long faces and longest in short faces (all P values ≤ 0.00008). The inferior-superior height was larger in Class III than both Classes I and II (both P values ≤ 0.003); there was no significant difference between Classes I and II in terms of height (P = 0.684). Height was the largest in long faces and smallest in short faces (all P values < 0.000001). The anterior-posterior length was the largest in Class III and smallest in Class II (all P values < 0.000001). Length was larger in short-face people versus normal- or long-face individuals (P ≤ 0.00003); nevertheless, long and normal faces did not differ in terms of length (P = 0.448). Subjects' age was not correlated with their MF positions (P ≥ 0.579, Pearson coefficient). Sex dimorphism existed only for height (P = 0.009, t-test) but not for length or width. CONCLUSIONS: The MF position may considerably differ in various horizontal or vertical growth patterns and sexes. This should be noted in mandible surgeries.

Three-dimensional analysis of mandibular and mental canals corroborating with teeth and mental foramen by cone beam computed tomography.

BACKGROUND: This study aimed to analyse the 3D patterns of the mandibular and mental canals (MDC and MC) referring to the surrounding prominent surgical landmarks such as teeth and mental foramen by cone beam computed tomography (CBCT). METHODS: CBCT scans of 354 patients aged 18-67 years with mandibular first premolar to second molar were included and reconstructed 3-dimensionally (3D) by mimics. The parameters of MDC and MC were measured referring to teeth and mental foramen. RESULTS: From the first premolars to the second molars, the mandibular canals showed a trend of gradually closer to the cementoenamel junction (CEJ) of the adjacent teeth and farther away from the buccal cortical plate. The distance of the MDC with the root apexes (RA) was relatively constant from the first premolar to the first molar, but became much closer to the second molar. About 10.8% of the second molars had MDC-RA distances of shorter than 2 mm, and 1.34% even had the MDC superior to the RA. Moreover, the Type III of MC presented in 66.0% of the subjects and had a relatively longer length. Besides, the existence of Type I MC may be related to the MDC featuring with close distances to the RA and CEJ of the adjacent teeth. CONCLUSION: Dentists and surgeons should know the patterns of mandibular and mental canals. A better understanding of the MDC and MC and their relationship to local anatomical landmarks may facilitate the planning of surgeries and alert potential nerve injuries in the operative procedures.

Diagnostic Accuracy of CBCT for the Detection of Accessory Mental Foramina Using Different Devices and Imaging Modalities

This study investigated the diagnostic accuracy of CBCT for detection of accessory mental foramina (AMFs) in dry mandibles using two different devices and three different CBCT imaging modalities. A total of 40 dry mandibles (20 per group) were selected to generate corresponding CBCT images, each with three different CBCT imaging modalities (high, standard, and low doses), using ProMax 3D Mid (Planmeca) and Veraview X800 (J. Morita). The presence, count (n), location, and diameter of the AMFs were measured on both dry mandibles and CBCT scans. The Veraview X800 with different imaging modalities showed the highest accuracy (97.5%), while the ProMax 3D Mid in low-dose imaging modality exhibited the lowest accuracy (93.8%). The most common AMF sites on dry mandibles were anterior-cranial and posterior-cranial, while anterior-cranial was the most frequent on CBCT scans. As for AMF diameter, the mean mesiodistal and vertical diameters on dry mandibles were 1.89 mm and 1.47 mm, respectively, which were greater or equal to the values obtained from CBCT scans. The overall diagnostic accuracy for assessing AMFs exhibited good results, but some caution is warranted when using a low-dose imaging modality with a large voxel size (400 µm).

Evaluation of the validity of mental foramen USG measurements by comparison with CBCT and determination of blood flow.

OBJECTIVES: To examine mental foramen (MF) morphology and morphometry in comparison with ultrasonography (USG) and cone-beam computed tomography (CBCT), and to determine the relationship between mental artery blood flow parameters and age, gender, dental status, alveolar crest height, mandibular cortical index (MCI) with USG. METHODS: A total of 120 MF and mental arteries of 60 patients (21 males and 39 females), including 20 patients in each group, aged 18-39, 40-59, and 60 years and above, were evaluated. The horizontal and vertical diameter of the MF and the distance between it and the alveolar crest were evaluated with USG and CBCT. In addition, mental artery blood flow parameters were examined by USG. RESULTS: When the horizontal diameter values of MF were compared in USG and CBCT measurements; the diameter was significantly lower in the measurements obtained by USG (p < 0.05). It was observed that there were no mental arteries whose blood flow could not be recorded, 31 (25.8%) had strong blood flow and 89 (74.2%) had weak blood flow. No significant correlation was observed between gender and blood flow parameters (p > 0.05). CONCLUSIONS: Considering that CBCT images are used as gold standard in our study, it may be said that USG is not as reliable as CBCT in evaluating the MF dimensions in the maxillofacial region. Nevertheless, USG is a suitable technique for determining the visualizing and blood flow of the MF.

Variantes anatómicas del foramen mentoniano / Anatomical variants of the mental foramen

El foramen mentoniano es un hito anatómico en la cara externa del cuerpo mandibular del que emergen el nervio mentoniano y su paquete vascular. Podemos observar más forámenes, tanto en la cara externa como en la cara lingual de la mandíbula. Se denominará foramen mentoniano accesorio si se comprueba su continuidad con el conducto mentoniano o con el conducto dentario inferior, y se llamará foramen lingual lateral si se continúa con el conducto dentario inferior y emerge en la superficie lingual, distal a la zona de caninos. Se pueden presentar otras variantes anatómicas menos frecuentes como la agenesia uni o bilateral del foramen mentoniano y la presencia del foramen incisivo. La detección de las variantes anatómicas del foramen mentoniano es de gran importancia en el planeamiento de diversos tratamientos invasivos en la zona, para evitar disturbios sensoriales y accidentes vasculares.

The mental foramen is an anatomical landmark on the external face of the mandibular body from which the mental nerve and its vascular bundle emerge. We can observe more foramina, both on the external aspect and on the lingual aspect of the mandible. It will be called accessory mental foramen if its continuity with the mental canal or the lower dental canal is verified, and it will be called lateral lingual foramen if it continues with the lower dental canal and emerges on the lingual surface, distal to the canine area. Other less frequent anatomical variants may occur, such as unilateral or bilateral agenesis of the mental foramen and the presence of the incisive foramen. The detection of the anatomical variants of the mental foramen is of great importance in the planning of various invasive treatments in the area, to avoid sensory disturbances and vascular accidents.

Do the location and dimensions of the mental foramen differ among individuals of different facial types and skeletal classes? A CBCT study.

STATEMENT OF PROBLEM: Knowledge about the location and dimensions of the mental foramen is important for surgical planning and implant placement in the posterior mandibular region. PURPOSE: The purpose of this clinical study was to assess the location and dimensions of the mental foramen in individuals of different facial type, skeletal class, and sex by means of cone beam computed tomography (CBCT) images. MATERIAL AND METHODS: CBCT images of 142 individuals (72 women and 70 men) were classified according to the facial type (dolichocephalic, mesocephalic, or brachycephalic) and skeletal class (I, II, or III). The vertical and horizontal locations of each mental foramen were evaluated on panoramic reconstructions, and the greatest height and width of the mental foramen were determined on multiplanar reconstructions. Also, the distances from the mental foramen to the alveolar crest and to the inferior cortex of the mandible were obtained. The data were compared by using the Kruskal-Wallis test and multiway analysis of variance (α=.05). RESULTS: The facial type, skeletal class, and sex did not influence the vertical (P=1.00) or the horizontal (P>.15) location of the mental foramen. The most frequent location of the mental foramen was between the first and second premolars and below their apices. The dimensions of the mental foramen were not influenced by the studied factors in men (P>.07); conversely, the mental foramen dimensions were influenced for women (P<.03). CONCLUSIONS: The most frequent location of the mental foramen was between the first and second premolars and below their apices. An influence of the facial type and skeletal class was observed on the dimensions of the mental foramen in women.

An evaluation of mandibular canal variations: a systematic review and meta-analysis.

The inferior alveolar nerve and vessels are carried via the mandibular canal, which extends bilaterally from the inferior alveolar foramen to the mental foramen. Bifid and trifid mandibular canals result from abnormal fusions of nerve canals. The purpose of this study was to provide an up-to-date and comprehensive analysis of the prevalence of mandibular canal variations among healthy adults, and to identify any potential ethnic, sex, or laterality predilections. The prevalence of the bifid mandibular canal was 18.87% and that of the trifid canal 1.3%. Unilateral variants were three times commoner than bilateral. Each mandibular half had four canals emanating from separate openings on the lingual surface of the mandibular ramus. Retromolar and forward canals were the predominant subtypes, followed by dental; buccolingual were the least frequent. The mean length and diameter of the bifid mandibular canal were 13.62 mm and 1.63 mm, respectively. The possibility of a bifid mandibular canal is a crucial consideration in dental medicine. Because anatomical variations of the mandibular canal are fairly common, awareness of them is essential for anatomy teachers and for surgeons who operate in the oromaxillofacial region.

Evaluation of accessory mental foramen and accessory infraorbital foramen with cone-beam computed tomography in Turkish population.

It was aimed to evaluate the frequency of accessory mental foramen (AMF) and accessory infraorbital foramen (AIOF) and analyse the correlation between these two foramina using cone-beam computed tomography (CBCT). The retrospective study reviewed the CBCT images of 1020 patients. The rates of AMF and AIOF were evaluated according to sex and age distributions. Correlations between the localizations of AMF and AIOF in the right and left jaws and the correlations between the occurrences of these foramina were evaluated. In the CBCT images of the 1020 patients, AMFs were detected in 48 patients, among which 14 were in the right half jaw, and 34 were in the left half jaw. AIOFs were detected in 143 patients, among which 65 were in the right half jaw, and 78 were in the left half jaw. Recognising and detecting AMF and AIOF with CBCT is important in terms of preventing complications that may occur in surgical procedures.

Mean Distance of Mental Foramen from Inferior Border of Mandible among Patients Visiting the Outpatient Dental Department in a Tertiary Care Centre.

Introduction: Among many anatomical landmarks in the human skull, the mental foramen is a stable landmark on the mandible. The diverse morphology of the mandible indicates the specific characteristics of such anatomical structures in each individual. The aim of this study was to find out the mean distance of mental foramen from the inferior border of the mandible visiting the Outpatient Dental Department in a tertiary care centre. Methods: A descriptive cross-sectional study was conducted among patients undergoing orthopantomogram in the Outpatient Dental Department of a tertiary care centre from 3 February 2022 to 31 July 2022. Ethical approval was obtained from the Institutional Review Committee. The patients with complete denture in the region of measurements were included in the study. A convenience sampling method was used. The point estimate was calculated at a 95% Confidence Interval. Results: Among 207 patients, the mean distance from the inferior border of the mandible to the lower border of the mental foramen was 11.83±1.83 mm (11.58-12.07, 95% Confidence Interval). Conclusions: The mean distance of mental foramen from the inferior border of the mandible was found to be similar to other studies done in similar settings. Keywords: gender; mandible; mental foramen.

Automatic detection of the mental foramen for estimating mandibular cortical width in dental panoramic radiographs: the seventh survey of the Tromsø Study (Tromsø7) in 2015-2016.

OBJECTIVE: To apply deep learning to a data set of dental panoramic radiographs to detect the mental foramen for automatic assessment of the mandibular cortical width. METHODS: Data from the seventh survey of the Tromsø Study (Tromsø7) were used. The data set contained 5197 randomly chosen dental panoramic radiographs. Four pretrained object detectors were tested. We randomly chose 80% of the data for training and 20% for testing. Models were trained using GeForce RTX 2080 Ti with 11 GB GPU memory (NVIDIA Corporation, Santa Clara, CA, USA). Python programming language version 3.7 was used for analysis. RESULTS: The EfficientDet-D0 model showed the highest average precision of 0.30. When the threshold to regard a prediction as correct (intersection over union) was set to 0.5, the average precision was 0.79. The RetinaNet model achieved the lowest average precision of 0.23, and the precision was 0.64 when the intersection over union was set to 0.5. The procedure to estimate mandibular cortical width showed acceptable results. Of 100 random images, the algorithm produced an output 93 times, 20 of which were not visually satisfactory. CONCLUSIONS: EfficientDet-D0 effectively detected the mental foramen. Methods for estimating bone quality are important in radiology and require further development.

Periosteum Classification and Flap Advancement Techniques Around the Mental Foramen.

Various surgical flap advancement techniques for bone regeneration have been described in the literature; however, the clinical challenges of managing tissue that contains scars or embedded foreign materials have not been thoroughly described, especially around metal foramen. Fibrotic and thickened scar periosteum as well as mental foramen restrict the tissue from responding in the same way as native tissue. Therefore, additional considerations and approaches must be considered to achieve tension-free flap closure. This article presents a flap advancement classification that describes three common clinical scenarios based on the periosteum and soft tissue quality and provides surgical approaches for tissue management in each classification, with a focus on flap advancement around the mental foramen.

Morphometric study for the localization of the mental foramen in relation to the vertical reference plane.

BACKGROUND: The mental foramen (MnF) is the anatomic landmark where the mental neurovascular bundle exits the mandible. Precisely determining the position of the MnF is necessary before all dentoalveolar therapeutic procedures performed in the mandibular premolar area. MATERIALS AND METHODS: For the study, we performed two ex vivo direct morphometric determinations on dry human dentate and edentate mandibles, and two in vivo imaging morphometric determinations through cone-beam computed tomography (CBCT) and orthopantomography (OPG) in dentate human patients. The following landmarks were used to locate the MnF: the distance between the MnF and the superior border of the mandible (MnF-SB), the distance between the MnF and the inferior border of the mandible (MnF-IB), and the position of the MnF in relation to the root apices of the posterior teeth. The results obtained from these data were processed statistically using the analysis of variance (ANOVA). RESULTS: By direct morphometry on dentate mandibles, the MnF was situated closer to the IB and by direct morphometry on completely edentulous mandibles, the MnF was located closer to the SB. In both direct morphometry studies, the MnF transverse diameter was larger than the vertical one, with the MnF having an oval shape. ANOVA for both direct morphometry studies showed that the distances MnF-IB and MnF-SB significantly vary statistically with interactions and depending on age (p<0.00001). The vertical diameter of the MnF significantly varies statistically depending on age, interactions and between studies, and its transverse diameter varies statistically significantly with interactions and depending on age (p<0.00001). According to OPG and CBCT imaging studies, the MnF was located closer to the IB, and the transverse diameter of the MnF was larger than the vertical diameter; such results are similar to the direct morphometry study performed on dry dentate human mandibles. Regarding the position of the MnF in relation to the root apices, it was most frequently located inferior to the root apices in 79.45% of cases, in 19.23% of cases it was located at the root apices level and in 1.31% of cases it was located superior (coronal) to the root apices. ANOVA for both imaging morphometry studies showed that the MnF-IB distance varies statistically significantly with the interactions, the study, the sex of the patients and their age, the MnF-SB distance varies statistically significantly with the interactions, the study and the patients' age (p<0.05), and the MnF diameters vary statistically significantly with interactions and patient age (p<0.05). CONCLUSIONS: The results of this study can help dental practitioners in improving dentoalveolar surgery procedures in the posterior mandible.

Assessment of the prevalence and length of the anterior and caudal loops of the mental nerve as anatomical variants of exiting the mandible at the mental foramen using cone-beam computed tomography: a systematic review and meta-analysis.

OBJECTIVES: This systematic review aimed to identify the studies that performed cone-beam computed tomography analysis of the prevalence and length of the anterior loop (AL) and caudal loop (CL) of the mental nerve. MATERIALS AND METHODS: An electronic database search was performed across PubMed, EMBASE, Web of Science, Scopus, the Cochrane library, and Google Scholar. Original studies reporting the frequency and length of the AL and CL were selected. Qualitative synthesis and meta-analysis were then conducted to assess the prevalence and length of the AL and CL and their associations with age, gender, sides, and dentition status. RESULTS: A total of 21 studies were included in this review. The pooled prevalence of the AL (95% confidence interval) of the mental nerve at the patient and side level was 51% (31-71%) and 53% (37-69%) while the mean anterior loop length was 2.08 (1.46-2.70) mm. The pooled prevalence of the CL and mean caudal loop length were 100% and 4.73 (3.44-6.01) mm. No significant associations were found between the prevalence and length of the AL and CL and age, gender, sides, and dentition status. CONCLUSIONS: Overall, the pooled prevalence and mean length of AL of the mental nerve varied among different populations while CL seems to be a constant anatomical landmark with a longer CL than AL. CLINICAL RELEVANCE: Surgeons performing inter-foraminal oral surgeries like dental implant placement and genioplasty should be aware of the possible distance of the AL and CL to avoid iatrogenic mental nerve injury.

Inferior Alveolar Nerve Lateralization Surgery for Implant Installation in Atrophic Posterior Mandible With Accessory Mental Foramen: A Challenge for the Usual Technique.

ABSTRACT: Implantology allows edentulous patients to smile and chew with confidence. However, the atrophy at posterior region of the mandible is still a challenge due the presence of the inferior alveolar nerve (iAN). The options of restoration with oral implants in this area with great atrophies are few and hazardous. The possibilities are: bone grafting, short implants, which are not always possible. So, the solution falls on the techniques of inferior alveolar nerve lateralization (IANL) or transposition. The knowledge of the anatomy and path of the IAN is decisive in this type of surgery. But anatomical variations may occur. Like the presence of an accessory mental foramen. This clinical study will present a relatively rare case of the occurrence of an accessory mental foramen that obliged to change the technique of iAN lateralization to contour this anatomical variance and install oral implants, maintaining the integrity of the iAN bundle.

Interexaminer agreement between two dental specialties for the detection of bifid mandibular canal and accessory mental foramen in cone-beam computed tomography / Concordancia inter-examinador entre dos especialidades odontológicas para la detección del canal mandibular bífido y foramen mental accesorio en tomografía computarizada de haz cónico

Introduction: The aim of this study was to assess the agreement between oral and maxillofacial radiologists (OMFR) and oral and maxillofacial surgeons (OMFS) for the detection of bifid mandibular canal (BMC) and accessory mental foramen (AMF) using cone-beam computed tomography (CBCT). Material and Methods: This retrospective study involved 22 examiners (11 OMFR and 11 OMFS) who independently assessed 30 CBCT volumes from patients (n = 60 hemi-mandibles) under preoperative radiographic evaluation for implant placement. The examiners scored the presence of BMC and AMF in each hemimandible. The interexaminer agreements were assessed using Fleiss' kappa statistics. Results: For intra-examiner agreement, 40% of the sample was reevaluated. The interexaminer agreement between OMFR and OMFS was slight (0.12) for the detection of BMC and fair (0.24) for AMF. The agreement among OMFR for detection of BMC was fair (0.22), and it was slight among OMFS (0.15). The agreement among OMFR for detection of AMF was substantial (0.61), and among OMFS it was fair (0.22). Agreements between OMFR and OMFS were slight for BMC and fair for AMF, independently of the years of experience. Intraexaminer agreement ranged from 60% to 90% among OMFR and from 55% to 90% among OMFS. Conclusion: A slight and a fair agreement between OMFR and OMFS was found for the detection of BMC and AMF, respectively. In general, OMFR obtained higher agreement among themselves, mainly for detection of AMF.

Introducción: El objetivo de este estudio fue evaluar la con-cordancia entre los radiólogos orales y maxilofaciales (ROMF) y los cirujanos orales y maxilofaciales (COMF) para la detección del canal mandibular bífido (CMB) y el foramen mentoniano accesorio (FMA) mediante tomografía computarizada de haz cónico. CBCT). Material y Métodos: Este estudio retrospectivo involucró a 22 examinadores (11 ROMF y 11 COMF) que evaluaron de forma independiente 30 volúmenes CBCT de pacientes (n = 60 hemimandíbulas) bajo evaluación radiográfica preoperatoria para la colocación de implantes. Los examinadores puntu-aron la presencia de CMB y FMA en cada hemimandíbula. Los acuerdos entre examinadores se evaluaron utilizando las estadísticas kappa de Fleiss. Resultados: Por concordancia intraexaminador se reeva-luó el 40% de la muestra. El acuerdo entre examinadores entre ROMF y COMF fue ligero (0,12) para la detección de CMB y regular (0,24) para FMA. La concordancia entre ROMF para la detección de CMB fue regular (0,22) y leve entre COMF (0,15). El acuerdo entre ROMF para la detección de FMA fue sustancial (0,61), y entre COMF fue justo (0,22). Los acuerdos entre ROMF y COMF fueron leves para CMB y justos para FMA, independientemente de los años de experiencia. La concordancia entre examinadores varió del 60 % al 90 % entre ROMF y del 55 % al 90 % entre COMF. Conclusión: Se encontró un acuerdo leve y justo entre ROMF y COMF para la detección de CMB y FMA, respec-tivamente. En general, se obtuvo mayor acuerdo entre ROMF, principalmente para la detección de FMA.

A cone-beam computed tomography study to assess anterior loop and other anatomic variations in mental foramen area in an iranian population / Un estudio de tomografía computarizada de haz cónico para evaluar el asa anterior y otras variaciones anatómicas en el área del foramen mentoniano en una población iraní

Purpose: This study aimed to determine the prevalence and length of the anterior loop (AL) of the inferior alveolar nerve, and evaluate the emergence direction of the mental nerve and the location of mental foramen in a group of Iranian patients. Material and Methods: This study was carried out on CBCT scans of 150 patients (57 males and 93 females; mean age 40.8 ±14.33 years). The presence and extent of the AL was determined in reconstructed images. The emergence path of the mental nerve was classified into three groups: anteriorly directed emergence, right-angled pattern of emergence, and posteriorly directed emergence. The location of mental foramen relative to adjacent premolars was determined. Results: AL was identified in 14.7% of the cases with a mean length of 1.39± 0.91 mm (range 0.25 to 3.50 mm). No significant differences were observed in the prevalence and extent of the AL between genders (p>0.05). The right-angled pattern of emergence was more dominant (43.7%). The most prevalent location of mental foramen was between the first and second premolars (68.3%). There was no significant association between the presence of AL with the path of emergence of the mental nerve (p=0.627) or the location of the mental foramen (p= 0.10 0). Conclusion: The prevalence of anterior loop was relatively low in the present sample (14.7%) with a length range of 0.25 to 3.5 mm. Due to the importance of this anatomic variation in implant surgery, it is suggested to carefully assess CBCT images before the surgical procedure to avoid neurosensory complications.

Propósito: Este estudio tuvo como objetivo determinar la prevalencia y la longitud del loop anterior (LA) del nervio alveolar inferior, y evaluar la dirección de emergencia del nervio mentoniano y la ubicación del foramen mentoniano en un grupo de pacientes iraníes. Material y Métodos: Este estudio se llevó a cabo en exploraciones de tomografía computarizada de haz cónico de 150 pacientes (57 hombres y 93 mujeres; edad media 40,8 ± 14,33 años). La presencia y extensión de la LA se determinó en imágenes reconstruidas. La vía de emergencia del nervio mentoniano se clasificó en tres grupos: emergencia dirigida anteriormente, patrón de emergencia en ángulo recto y emergencia dirigida posteriormente. Se determinó la ubicación del foramen mentoniano en relación con los premolares adyacentes. Resultados: Se identificó LA en el 14,7% de los casos con una longitud media de 1,39± 0,91 mm (rango 0,25 mm a 3,50 mm). No se observaron diferencias significativas en la prevalencia y extensión de la AL entre sexos (p>0,05). El patrón de emergencia en ángulo recto fue más dominante (43,7%). La localización más prevalente del foramen men-toniano fue entre el primer y segundo premolar (68,3%). No hubo asociación significativa entre la presencia de AL con la vía de emergencia del nervio mentoniano (p=0,627) o la ubicación del foramen mentoniano p=0,100).Conclusión: La prevalencia de asa anterior fue rela-tivamente baja en la presente muestra (14,7%) con un rango de longitud de 0,25 mm a 3,5 mm. Debido a la importancia de esta variación anatómica en la cirugía de implantes, se sugiere evaluar cuidadosamente las imágenes de tomografía computarizada de haz cónico antes del procedimiento quirúrgico para evitar complicaciones neurosensoriales.

Morphometric studies of supraorbital foramen, infraorbital foramen and mental foramen in a thai population related with nerve blocks / Estudios morfométricos del foramen supraorbitario, foramen infraorbitario y foramen mental en una población tailandesa relacionados con bloqueos nerviosos

SUMMARY: The aim of this study was to study the anatomical landmarks and variations of supraorbital, infraorbital, and mental foramina. One hundred and sixty Thai dry skulls were randomly selected from the Forensic Osteology Research Center. The distances of the parameters were measured by using Vernier caliper. The supraorbital foramen could be found in a notch form 13.8 %, single supraorbital foramen accounted for 82.5 %, and supraorbital foramen with an accessory foramen represented 3.8 %. Single infraorbital foramen was found 90.0 %, and infraorbital foramen with an accessory foramen represented 10.0 %. Single mental foramen was observed 96.6 %, and the frequency of mental foramen with an accessory foramen was determined 3.4%. The majority of infraorbital foramina (48.0 %) was detected above the second premolar area. 19.0 % of the infraorbital foramina was seen in the region between the first premolar and the second premolar, and 22.8 % of the infraorbital foramina was located between the second premolar and the first molar. The infraorbital foramen is anatomically positioned above the first molar (10.2 %). The majority of mental foramina (53.5 %) can be identified below second premolar area. The region between the first premolar and the second premolar is the site for the mental foramen 26.0 % of the total variations. The region between the second premolar and the first molar is the site for the mental foramen 16.9 % of the total variations. The mental foramen is approximately situated below the first molar (3.6 %). The present study of anatomical variations of various foramina demonstrates a useful application in cosmetic and ophthalmic plastic surgery. The findings could improve the efficacy of the surgeons and accuracy for the indicated localization of these foramina during maxillofacial operations and local anesthetic procedures.

RESUMEN: El objetivo de este estudio fue estudiar los puntos de referencia anatómicos y las variaciones de los forámenes supraorbitario, infraorbitario y mental. Ciento sesenta cráneos secos tailandeses fueron seleccionados al azar del Centro de Investigación de Osteología Forense. Las distancias de los parámetros se midieron utilizando un calibre Vernier. El foramen supraorbitario se pudo encontrar en forma de muesca el 13,8 %, el foramen supraorbitario único representó el 82,5 % y el foramen supraorbitario con un foramen accesorio representó el 3,8 %. El foramen infraorbitario único se encontró en un 90,0 % y el foramen infraorbitario con un foramen accesorio representó el 10,0 %. Se observó foramen mental único 96,6 % y se determinó la frecuencia de foramen mental con foramen accesorio 3,4 %. La mayoría de los forámenes infraorbitarios (48,0 %) se detectaron por encima del área del segundo premolar. El 19,0 % de los forámenes infraorbitarios se observó en la región entre el primer premolar y el segundo premolar, y el 22,8 % de los forámenes infraorbitarios se ubicó entre el segundo premolar y el primer molar. El foramen infraorbitario se ubica anatómicamente por encima del primer molar (10,2 %). La mayoría de los forámenes mentales (53,5 %) se pudieron identificar inferior al área del segundo premolar. La región entre el primer premolar y el segundo premolar es el sitio del foramen mental 26,0 % de las variaciones totales. La región entre el segundo premolar y el primer molar es el sitio del foramen mental 16,9 % del total de variaciones. El foramen mental se sitúa aproximadamente por debajo del primer molar (3,6 %). El presente estudio de variaciones anatómicas de estos forámenes demuestra una aplicación útil en la cirugía plástica y oftálmica. Los hallazgos podrían mejorar la eficacia de los cirujanos y la precisión para la localización de estos forámenes durante las operaciones maxilofaciales y los procedimientos anestésicos locales.

Left Accessory Mental Foramen in Dry Mandibles in Department of Anatomy in a Medical College: A Descriptive Cross-sectional Study.

INTRODUCTION: The presence of accessory mental foramen is one of the anatomical variations in the mandible. The occurrence of accessory mental foramen can differ in terms of number, shape, and size or there can even be an absence of it. The aim of this study was to find out the prevalence of left accessory mental foramen in dry mandibles in the Department of Anatomy of a medical college. METHODS: This descriptive cross-sectional study was conducted in a medical college among dry mandibles from 10 January 2021 to 10 June 2021. Ethical approval was obtained from the Institutional Review Committee (Reference number: 207202005). Intact dry mandibles were studied for the prevalence of left accessory mental foramen. A convenience sampling technique was used. Point estimate and 90% Confidence Interval were calculated. RESULTS: Among 47 dry mandibles, the prevalence of left accessory mental foramen was found to be 4 (8.51%) (1.81-15.21, 90% Confidence Interval). The mean diameter of the left accessory foramen was found to be 1.02±0.03 mm. CONCLUSIONS: The prevalence of left accessory mental foramen in mandibles was similar to the studies done in similar settings.

Cone Beam Computed Tomography based evaluation of position of mental foramen and its relation to apices of mandibular posterior teeth in a sample of Pakistani population.

OBJECTIVE: To radiographically determine the mental foramen position, its distance to the nearest apex and the prevalence of anterior loop of mandibular nerve using cone-beam computed tomography scans. METHODS: The cross-sectional study was conducted at the Aga Khan University Hospital, Karachi, from January to June 2020, and comprised cone-beam computed tomography scans of males or females of Pakistani origin aged 15-65 years with intact mandibular dentition and fully formed roots with matured apex. The scans were analysed to determine the horizontal position of mental foramen and to classify it according to the Tebo and Telford classification. The vertical distance from mental foramen to the nearest tooth apex was measured and the mandibular nerve configuration was determined. Data was analysed using SPSS 23. RESULTS: Among the 96 scans, the most frequent location of mental foramen MF was along the long axis of 2nd premolars for both right 50(52.1%) and left 49(51%) sides, followed by between 1st and 2nd premolars for both right 28(29.2%) and left 38(39.6%) sides. The mean minimum distance from mental foramen to the nearest root apex was 3.75±2.59mm and 3.99±2.26mm on right and left sides, respectively. There was bilateral symmetry on both sides. The most frequent mandibular nerve configuration on the right 69(72.6%) and left 75(78.1%) sides, with anterior loop being the least common; right side 3(3.2%) and 5(5.2%) left side. Conclusion: The most common position of mental foramen was along the long axis of 2nd premolars while the anterior loop was the least common.

Morphometric Analysis of the Mental Foramen Variation in an Iraqi Population by Using Cone-Beam Computed Tomography.

ABSTRACT: The effects of gender, side, and ridge condition on the position of the mental foramen (MF) were investigated in this research. A total of 122 cone-beam computed tomography scans were chosen from healthy patients with age ranging from 18 to 72 years. The following parameters were used to evaluate images: MS-MF (horizontal distance to the mandibular symphysis from the anterior MF limit) and MB-MF (vertical measurement of distance from the inferior boundary of the mandible to the lower border of the MF). The mean distance between the MF and mandibular symphysis was 20.98 ±â€Š1.95. The average measurement between the MF and the mandible's lower boundary was 10.36 ±â€Š1.63. The horizontal distance was slightly different between males and females (21.5 ±â€Š1.59 and 20.6 ±â€Š1.6, respectively). In terms of gender and ridge condition, a significant difference in vertical distance (10.97 ±â€Š1.14 versus 9.9 ±â€Š1.24 and 10.13 ±â€Š1.5 versus 10.55 ±â€Š1.07, respectively) was observed. By contrast, in vertical and horizontal distances, significant differences were noted between edentulous men and women. Meanwhile, a significant difference between dentate male and female patients was found at vertical distances only. In conclusion, in both vertical and horizontal measurements, the location of the MF was higher in males than in females and edentulous more than dentate.