Interforaminal Region Research Articles

CBCT study on the prevalence, morphology and position of the mandibular incisive canal in a North-Brazilian population.

BackgroundThe mandibular incisive canal (MIC) is an anatomic structure to be considered in treatment planning for surgeries in the anterior region of the mandible. Awareness of the MIC increased with the use of 3D imaging for treatment planning, such as cone beam computed tomography (CBCT). This study aimed to use CBCT to assess the prevalence, morphology and position of the MIC among North-Brazilians. Material and MethodsThe sample consisted of CBCT scans of 100 hemi-mandibles (50 individuals) that were assessed for the absolute (n) and relative frequency of the MIC. The morphological component of this study was the diameter (mm) of the detected MIC in five anatomic sites between the mental foramen and the midline. Within the interformainal region, the position of the MIC was assessed by measuring (mm) the distances between the MIC and the basal, vestibular and lingual cortical bone surfaces. ResultsThe prevalence of the MIC was >76% considering the different anatomic regions screened in CBCT. The mean diameter of the MIC progressively reduced from 1.29 mm to 0.86 throughout the five anatomic regions measured. The position of the MIC showed a downward trajectory away from the lingual cortical bone surface. ConclusionsMIC was a highly prevalent anatomic structure in the studied sample. The funnel-shaped outline of the MIC and its trajectory into the interforaminal region highlighted a major risk of damage to the neurovascular bundle in surgeries (e.g. implant placement) that are close to the mental foramen and the vestibular cortical bone. Key words:Anatomy, cone beam computed tomography, imaging, mandibular incisive canal, oral radiology.

Prevalence of Anterior Loop and other Patterns of Mental Nerve in a Sample Population of an Indian City: A Retrospective Study.

Introduction:The final portion of the inferior alveolar nerve (IAN), the mental nerve (MN), is a general somatic afferent nerve that provides sensation to the lip, chin, and gingival tissue. Three patterns of MN have been observed – straight, perpendicular or vertical, and anterior loop (AL) of MN. The interforaminal region of the mandible possesses a MN with a path that creates an AL before entering the mental foramina. The aim of the study is to evaluate the presence of AL of MN using cone-beam computed tomography (CBCT) and to measure the length of the AL of MN, if present, also to evaluate the prevalence of other anatomical patterns of MN – straight and vertical patterns.Materials and Methods:Mandible CBCT of 400 patients with the age of 20 years onward was included in the study. The images obtained were assessed for the different patterns of MN – straight, vertical, and ALs. The statistical analysis was done using the Chi-square test, paired t-test, and sample t-test.Results:Out of 400 CBCT scans comprising 800 hemimandibles, straight pattern was observed in 67.1%, vertical pattern in 26%, and Anterior Loop in 6.9%. The prevalence of AL pattern was 6.9%. AL length was found to be in a range of 2.4–6.6 mm.Discussion:Surgical trauma or injury to the AL of MN is possible during implant surgery in the interforaminal area of the mandible if AL is not assessed preoperatively.

RETROSPECTIVE ANALYSIS OF NEUROSENSORY DISTURBANCES RELATED TO DENTAL IMPLANT PLACEMENT IN MANDIBULAR INTERFORAMINAL REGION

The aim of this study is to evaluate the risk of neurosensory disturbances resulting from the injury of the anterior loop of the inferior alveolar nerve (IAN) in dental implant surgery with panoramic radiography. Panoramic radiographs of 1614 consecutive patients treated with dental implants were examined, and patients with implants located at a distance less than 5 mm to the mental foramen were recorded. Paresthesia, anesthesia, neuropathic pain was investigated retrospectively. In 405 patients, the implants were located in a distance less than 5 mm to the mental foramen. A range of 0.6 mm to 5 mm distance was detected between the mental foramen and these dental implants. No patient complained of bilateral paresthesia. In five (2.06%) of the 242 regions, it was found that patients had permanent unilateral paresthesia in their lower lips. In conclusion, panoramic radiography is not an entirely reliable imaging method for dental implant planning in the interforaminal region. Methods that are more sophisticated may be required to assess the risk of neurosensory disorder before treatment.

Investigation the anterior mandibular lingual concavity by using cone-beam computed tomography.

In the presence of lingual concavity in the mandible, the cortical perforation and consequently the life-threatening intraoral haemorrhages obstructing the upper respiratory tract may be seen during the surgical intervention. The present study was aimed to determine the prevalence of lingual concavity in the interforaminal region and its relationship with gender and dentate status. The images of 106 patients who underwent cone-beam computed tomography (CBCT) between 2016 and 2017 in Department of Dental and Maxillofacial Radiology Department of Faculty of Dentistry of Ondokuz Mayıs University were retrospectively examined. The images were obtained using a Galileos device (98 kVp, 15-30 mA). The bone height and width in interforaminal region and the frequency of lingual concavity were analysed. Of patients involved in the present study, 42.5% were male and 57.5% were female After the examinations performed, the bone was morphologically classified into four classes as type I lingual concavity, type II inclined to lingual, type III enlarging towards labiolingual and type IV buccal concavity. Type III (77.9%) was the most common type in the anterior region, followed by type II (16.5%), type I (4.7%) and type IV (0.9%). The lingual concavity angle was 76.5 ± 3.69º and the concavity depth was 2.09 ± 0.34 mm. The lingual concavity can be detected by using the cross-sectional CBCT images and the complications related with lingual cortical perforation can be prevented.

Comparison of stresses in monoblock tilted implants and conventional angled multiunit abutment-implant connection systems in the all-on-four procedure

BackgroundThe All-on-four dental implant method is an implantology method designed to provide a comfortable prosthetic treatment option by avoiding advanced surgical procedures. This research aims to compare and evaluate the stress and tension values in conventional angled multiunit abutment-implant connection systems and monoblock dental implants used in the all-on-four procedure with finite element analysis.MethodsTwo master models were created by placing four implants connected to multiunit abutments (group A) in the interforaminal region of a completely edentulous mandible and four monoblock implants (group B) in the same region of another completely edentulous mandible. Group A implants were classified according to their diameter as follows: 3.5 mm (M1A), 4.0 mm (M2A), and 4.5 mm (M3A). Similarly, group B implants were classified as M1B, M2B, and M3B. In the six models rehabilitated with acrylic fixed prostheses, a 100 N force was applied to the anterior implant region, and a 250 N force was applied to the posterior cantilever in both axial and 30° oblique directions. Von Mises stresses were analyzed in the bone and implant regions of all models.ResultsM1A and M1B, M2A and M2B, and M3A and M3B were compared with each other under axial and oblique forces. The maximum Von Mises stresses in the bone around implants and the prosthesis screws, and the maximum and minimum principal stresses in the cortical and trabecular bone in group A models were significantly higher than those in group B models.ConclusionsIn monoblock implant systems under axial and oblique forces, higher stress is accumulated in the bone, prosthesis screw and implant compared to multiunit abutment-implant connection systems.

Finite Element Analysis of Stress Distribution in Mandibles with Different Bone Types Loaded by Implant-Supported Overdentures with Different Localizations of Locator Attachments.

Prosthetic rehabilitation of completely edentulous patients has been traditionally performed with complete dentures for many years. However, patient complaints are reported due to insufficient retention and high mobility of mandibular dentures. Therefore, in these patients, overdenture prostheses, which are usually made by placing at least two implants in the interforaminal region of the mandible, have become widespread. In these prostheses, bar, stud, magnetic, or ball and locator attachments are used. This study aimed to evaluate the stress on mandibles by an overdenture with locator attachments supported by two implants placed on three different bone types in three different regions. Finite element analysis (3D) was used to design a mandible and overdenture. Two implants and locator attachment systems were placed into the lateral incisor, canine, and premolar regions. In computer-generated mandible and overdenture models, a force of 100 N was loaded obliquely and vertically from the mandibular first molar teeth region; then, the values obtained from the forces were compared. Eighteen analyses were performed with two different loading options in nine different models. Von Mises, compressive, and tensile stress values were analyzed. As the bone type changed from D1 to D3, the stresses on the bone increased in direct proportion. However, with all three bone types, lower tensile values were found in cortical bone in an above-implant removable prosthesis supported by an implant in the lateral incisor region. Biomechanically, the lateral incisor and canine regions were more advantageous than the first premolar tooth region in prosthesis designs where two implants were used in all bone types.

Assessment of Anterior Loop of Inferior Alveolar Nerve and Its Anatomic Variations with Age, Gender, and Dentition Status in Indian Population: A CBCT Study.

Background The posterior region of the mandible is more often related to iatrogenic errors, but the interforaminal region is also not spared for neurovascular complications. This study aimed to use CBCT images to evaluate the prevalence of anterior nerve looping and its variations with age, gender, and dentition status. Methods This retrospective study was carried out by studying 600 CBCT scans retrieved from archival records of a CBCT center in Lucknow. The scans were inspected by two trained investigators. The length of the anterior loop was measured using the measuring tool of Carestream 3D imaging software. Descriptive and analytical tests were performed. Results The prevalence of the anterior loop of the inferior alveolar nerve was found to be 56%. The prevalence was found to be more on the right side (29.0%) compared to the left side (27.0%). The most common anterior looping of the inferior alveolar nerve was type 3 followed by type 1. Males were found to have significantly higher loops compared to females. The number of loops was found to decrease significantly with age. The mean length of the loop was found to vary from 1.14 to 1.61 mm. Conclusion The anterior looping of IAN is very much prevalent in the Lucknow population. The use of the CBCT technique and appropriate preplanning prior to surgery or implant placement should be performed to prevent nerve injury.

Evaluation of immediately loaded mandibular four vertical versus tilted posterior implants supporting fixed detachable restorations without versus with posterior cantilevers.

Distally inclining posterior implants may be technically challenging in certain situations. The presence of a posterior cantilever can also exert unfavorable forces on supporting implants. The aim of the present study was to evaluate and compare peri-implant soft and hard tissues around 4 mandibular interforaminal implants having tilted posterior implants with posterior cantilevers, versus vertical implants, 2 in the interforaminal region and 2 in the first molar regions, without posterior cantilevers. All implants supported full-arch fixed detachable restorations opposing complete dentures. A total of 80 implants were placed flapless in the mandibles of 20 edentulous participants. Four implants were placed for every participant, who were randomly assigned into 2 equal groups. Axial group implants were vertically aligned, with 2 implants in the interforaminal area and 2 in the molar area. Tilted group implants have 2 anterior axial and 2 posterior distally inclined implants. Interim screw-retained prostheses converted from pre-existing dentures were immediately fabricated and loaded on the same day of surgery. After awaiting period of 3months, all participants received fixed detachable metal acrylic resin definitive restorations. A follow-up protocol of 3, 6, and 12months was scheduled to assess the modified gingival index, modified plaque index, peri-implant probing depth, implant stability, and marginal bone level and bone density changes. No statistically significant differences (P > .05) were found in the modified gingival index, modified plaque index, peri-implant probing depth, implant stability, bone density, and marginal bone level between the axial and tilted implant groups after the 1-year follow-up period. Placing 4 flapless immediately loaded implants in mandibular edentulous patients that supported full-arch fixed restorations provided high implant and prosthodontic success rates whether posterior implants were tilted with posterior cantilevers or vertically aligned without posterior cantilevers. Pan African Clinical Trial Registry database, PACTR201907776166846. Registered 3 July 2019, www.pactr.org .

Bone quality and quantity of the mandibular symphyseal region in autogenous bone grafting using cone-beam computed tomography: a cross-sectional study

BackgroundBone volume plays a pivotal role in the success of dental implant treatment. Autogenous bone grafts should be harvested from reliable sites in the maxillofacial region. This study sought to assess the quantity and quality of bone in the mandibular symphysis for autogenous bone graft harvesting using cone-beam computed tomography (CBCT).MethodsThis cross-sectional study evaluated the CBCT scans of 78 adults presenting to three oral and maxillofacial radiology centers. The vertical (VD) and horizontal (HD) alveolar bone dimensions, cortical thickness (CT), and cancellous to cortical bone ratio (C/C) were measured in the interforaminal region of the mandible at the sites of central incisor to first premolar teeth. The interforaminal distance (ID) and the anterior loop length were also measured. Nonparametric statistical tests were used to analyze the data with respect to sex, age, and tooth position.ResultsThe median VD, HD, and CT of the symphysis were 20.21 (3.26), 4.13 (0.37), and 2.25 (0.23) mm, respectively. The median C/C was 1.51 (0.11). The median ID was 52.24 (8.24) mm, and the median anterior loop length was 1.82 (1.06) mm. Significant differences were observed in all parameters among different teeth. Most of the measured parameters were greater in males compared with females. There were significant differences in ID, VD, and CT between different age groups.ConclusionsThe quantity and quality of the available bone in the mandibular symphysis for bone graft harvesting vary by gender, age, and harvesting site, necessitating careful preoperative evaluation.

Retrospective Evaluation of Two-Implant-Supported Mandibular Overdentures with Radiographic and Clinical Aspects.

The aim of this retrospective study was to evaluate the clinical performance of two implants supporting mandibular overdentures by means of clinical and radiologic parameters, and also to explore the relationship of marginal bone loss with implant-/patient-related factors and soft tissue parameters. Data of patients who had undergone insertion of two implants into the interforaminal region between November 2012 and December 2016 using three different implant systems were retrieved from the archival records. Age, sex, implant length, implant diameter, observation period, mobility, and soft tissue parameters were recorded. Marginal bone levels and interimplant distances were measured with computer software on panoramic radiographs obtained at 3 months and at the recall session. A total of 43 patients with 86 implants were included in the study. Patients were evaluated with an average observation period of 41.79 months. Among the evaluated parameters, Gingival Index, Bleeding Index, and implant diameter were found to have significant effects on the marginal bone loss (P < .05). However, no significant effects of sex, age, implant length, observation period, and interimplant distance were observed on the marginal bone loss. No implants showed peri-implantitis or mobility, while eight implants showed peri-implant mucositis. Within the limitations of this study, it can be concluded that peri-implant soft tissue health and the diameter of the implant have an important effect on the marginal bone loss as well as the success of two-implant-supported mandibular overdentures.

Rehabilitation of extremely atrophic edentulous mandible in elderly patients with associated comorbidities: a case report and proof of concept

BackgroundOral rehabilitation of the atrophic mandible is, most of the time, a challenging procedure, especially in elderly patients with associated comorbidities.Case presentationThis clinical report describes the rehabilitation of an extremely atrophic mandible using an overdenture supported by four splinted implants, two of which are placed in the interforaminal region and the other two bypassing the inferior alveolar nerve at the level of the antegonial notch. A passive-fit bar structure splinting the four inserted implants was designed to compensate for mandibular flexure, to reduce the amount of strain on the implants, and avoid bone resorption and prosthetic failure. The 14-month postoperative cone-beam computed tomography (CBCT) and the clinical follow-up showed the bilateral integrity of the inferior alveolar nerve and the successful restoration of the atrophic edentulous mandible with a significant improvement in the patient’s quality of life.ConclusionsThe applied technique depicts several benefits such as a minimally invasive approach, reduced number of surgical interventions, reduced total treatment time, reduced treatment costs, and higher psychological acceptability.

Tomographic evaluation of the mandibular nerve in the mental region and its surgical implications: a cross-sectional study

The aim of this study was to evaluate the prevalence and length of the anterior loop (AL) of the inferior alveolar nerve, nerve emergence from the mental foramen, and prevalence of sensory disorders after implant placement in the interforaminal region. Four hundred and fifty hemimandibles (225 patients) were evaluated using cone beam computed tomography and panoramic radiographs. Information on the presence of sensory disorders was obtained from the medical records. AL prevalence was 13.6% and mean AL length was 1.25 mm. The false-negative rate for the identification of the AL using panoramic radiography was 58.6%. Straight nerve emergence from the mental foramen was the most prevalent (62.7%), followed by anterior (21.8%) and posterior (15.6%) emergence. The incidence of sensory disorders was 4.4%, and 1.1% were related to the presence of the AL. When implants were placed within the planned distance of the mental foramen or further, 1.2% had sensory problems associated with the presence of the mandibular incisive canal. In cases of distances smaller than planned, 12.9% had sensory alterations. Only five (1.1%) had the AL, with a length between 0 and 4.5 mm. However, in four cases, the planned distance was respected and, even so, there was a sensory disorder. Posterior nerve emergence from the mental foramen was associated with a higher prevalence of AL.

ADEQUACY OF THREE DIMENSIONAL MINIPLATE IN TREATMENT OF MANDIBULAR FRACTURE IN INTERFORAMINAL REGION

Background: Mandible is one of the commonly fractured bone due to trauma, assault and falls. Treatment includes closed and open methods. Methods of open reduction and internal fixation have changed and di­versified enormously in the past few years. Champy’s miniplate fixation, dynamic compression plating has become a standard approach. More recently, three dimensional miniplates have been developed by Farmand which may be effectively used in mandibular fractures. The aim of this study was to check the adequacy of three dimensional miniplate in man­agement of mandibular fracture occurring in the interforaminal region. &#x0D; Methods: A prospective clinical study was carried out in patients attend­ing Emergency Department and Department of Oral and Maxillofacial Surgery, Nobel Medical College and Teaching Hospital (NMCTH) suffer­ing from mandibular fractures in interforaminal region from May 2018 to January 2019. &#x0D; Results: A total of 17 patients with 18 fracture in interforaminal region, all male were included in the study. The age ranged from 16 to 50 years with a mean of 29.17 ± 9.48. Road traffic accident was the leading cause of injury with 15 out of 17 patients (88.23%). There was no incidence of wound infection, wound dehiscence, malunion, nonunion, plate fracture within the follow up period of 3 months. One fracture was unstable on 1st postoperative day and also had mildly deranged occlusion which was man­aged with intermaxillary fixation for two weeks. &#x0D; Conclusions: Three dimensional plates fulfills the treatment goals of ad­equate stabilization and fixation of mandibular interforaminal fractures.

Three-dimensional radiographic assessment of the mandibular interforaminal donor site in different vertical facial growth types

PurposeTo assess volumetrically, the impact of vertical facial growth types (VFGT) on the mandibular interforaminal region as a potential bone donor site. Material and methods60 cone beam computed tomography (CBCT) scans of adult individuals were classified in three groups according to their SN-GoGn angle: hypodivergent group (hG) (N=20), normodivergent group (NG) (N=19) and hyperdivergent group (HG) (N=21). Total harvestable bone volume (TBV), cortico-cancellous bone volume (CBV-cBV), and cortical bone surface (CBS) were evaluated. ANOVA test followed by Tukey post hoc tests were used to compare the mean continuous outcomes according to their VFGT. ResultsThe whole sample showed a mean TBV of 1376.32±541.01mm3, CBV of 468.52±121.54mm3 and cBV of 908.73±474.71mm3. The mean CBS amounted to 782.58±146.80mm2.The comparison between the groups stated a significantly different mean TBV and cBV (-p-value<0.001). The mean CBS was significantly different (-p-value=0.015): the smallest for the NG, but not significantly different (-p-value<0.001): the highest for the HG, intermediate for the NG and the smallest for the hG. ConclusionHypodivergent individuals have the thickest cancellous bone suitable for an onlay bone graft, while hyperdivergent individuals have the thinnest bone ideal for a 3D grafting approach.

Novel method to obtain human non-separated histological samples for the assessment of peri-implant soft tissue response: A feasibility study.

To introduce a standardized and less invasive clinical model that provides histological information on the abutment-mucosa interface in humans. New experimental healing abutments were left in an open healing position on bone-level implants in the interforaminal region of the mandibles in six edentulous patients. The one-piece abutments were hollow cylinder-shaped with two lateral openings that allow for ingrowth of the peri-implant mucosa into the central abutment cavity. After three months of healing, abutments and ingrown mucosa were sampled and processed for histological analysis in a non-separated resin-embedding technique. To test the validity of the new model, the ingrown tissue was compared to the peri-implant mucosa around the same samples. None of the experimental abutments exhibited signs of failure, and all samples showed mucosal ingrowth to the inner-abutment cavity. Comparison of ingrown tissue and peri-implant mucosa revealed no significant differences regarding the traits: tissue morphology, quality of collagen fibers, and adherence to the abutment. Ingrown mucosa exhibited a tendency for higher leukocyte infiltration. The presented model is a promising approach to reduce invasiveness during the sampling process for human non-separated abutment biopsies.

Cone-beam computed tomography evaluation of prevalence and location of mandibular incisive canal in patients attending King Saud University Dental Hospital.

OBJECTIVE:This study aims to facilitate a surgeon's preoperative assessment by detecting the prevalence, location, and course of the mandibular incisive canal (MIC) in our population.METHODOLOGY:A retrospective study was conducted at King Saud University, Riyadh, Saudi Arabia. A total of 93 cone-beam computed tomography (CBCT) scans of patients aged 18–50 years were taken. The images were reformatted from the sagittal sections to para-sagittal sections at premolars, canines, lateral incisors, and central incisors measured to the distance of MIC to the tooth apex, to the inferior border of the mandible, to the buccal cortex, and to the lingual cortex.RESULTS:MIC among the patients was found to be present in 96.8% of the total subjects. Prevalence between genders showed that it was present in 97.9% of the male patients and 95.5% of the female patients. The average distance from the buccal cortex is 4.88, the lingual cortex is 5.54, inferior border is 9.94, and root apices is 7.67. The age-wise and gender-wise comparison of a mean distance of MIC to the different surfaces in the different cross-sections showed that there is no correlation, and there is a significant correlation, respectively.CONCLUSION:The detection of the MIC presence and location using CBCT should be earnestly considered for surgical procedures that are intended to be done in the interforaminal region.

Effect of different mini implants distribution for mandibular overdenture cases on maxillary ridge height. retrospective radiographic study

Purpose. The purpose of the study is to evaluate the maxillary ridge change under complete dentures opposed by mandibular overdentures assisted by four mini-implants, in case of inter-foraminal distribution or in case of wide distribution after wearing dentures for 6 years. Methods and material. The subjects enrolled for this study (n = 20). They were treated with maxillary complete dentures, randomly assigned into two equal groups: group І received mandibular overdenture assisted by four mini implants distributed equally in the inter-foraminal region exposed to immediate loading protocol. Group II received mandibular overdenture assisted by four mini-implants (two inserted in canine region and two inserted in first molar region) exposed to immediate loading protocol. Radiographic evaluation of maxillary bone height using digital panorama for every patient of both groups recorded at the time of mini-implants insertion and after 6 years. Results: The results showed non- significant differences using independent t-test between wide & inter-foraminal distribution groups for midline, premaxilla. While, for maxillary tuberosity, the results give significant difference between wide & inter-foraminal distributions at significant levels P Conclusion: the combination syndrome also may occur in conventional maxillary dentures opposed by mini implants assisted mandibular overdentures and wide mini implants distribution has similar effect as inter-foraminal distribution in the maxillary alveolar ridge resorption.

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.

A CBCT aided assessment for the location of mental foramen and the emergence pattern of mental nerve in different dentition status of the Saudi Arabian population

Objective: The anatomy of mental foramen (MF) is a noteworthy landmark during any surgical procedures in the inter-foraminal region. Thus, the study aims at evaluating the location of MF and the emergence pattern of MN in three status of dentition in Saudi Arabian population. Material and Methods: In a prospective study, we have analyzed 240 cone beam computed tomography (CBCT) for the location of MF and the emergence pattern of MN. The study comprising three groups, namely dentulous, partially edentulous and edentulous, each having eighty CBCT scans. We presented the data in percentages. The chisquare and McNemar’s test were used for testing association and pair-wise analysis, respectively. Results: The most common location of MF was below the apex of the second premolar irrespective of dentition status, with 54.2% in right and 60% in the left side of the jaw. Among the dentition status, left side of the mandible has shown significant variation for the location of MF, whereas gender and age showed variation in the right side. Anterior loop (AL) (Type-III) the emergence pattern of MN was the highest in all dentition status, with 51.7% in right and 53.8% on the left side. The variation in the emergence pattern of MN in terms of gender and side of the jaw was statistically significant. Conclusion: In the Saudi Arabian population, the apex of second premolar and type III/AL was the most prevalent location of MF and the emergence pattern of MN, respectively. KEYWORDS Anterior loop; Cone beam CT; Mandible; Mental foramen; Mental nerve.

Radiographic Evaluation of the Effect of Different Mini-implants Distribution on Posterior Mandibular Ridge Hight In Mandibular Mini-implants Assisted Overdentures Cases. An 6-Year Retrospective Study

ABSTRACT Statement of problem: Mandibular overdentures assisted by mini-implants induce sever bone changes in posterior mandible. Purpose: This study aimed to evaluate the posterior mandibular ridges height changes using the digital panoramic radiographic technique under mandibular overdentures assisted by four mini-implants, in case of interforaminal distribution and in case of wide distribution after wearing overdentures for 6 years. Methods and material: The subjects enrolled for this study (n = 20). They were treated with maxillary complete dentures, randomly assigned into two equal groups: group І received mandibular overdentures assisted by four mini-implants distributed equally in the interforaminal region, exposed to immediate loading protocol. Group II received mandibular overdentures assisted by four mini-implants (two mini-implants inserted in canine regions and two mini-implants inserted in first molar regions) exposed to immediate loading protocol. Digital panoramic radiographic evaluation of posterior mandibular region was done for every patient of both groups, recorded at the time of mini-implants insertion and after 6 years. Results: There was statistically significant difference in bone heights changes between interforaminal and wide distribution groups after six years. There is bone apposition in the wide distribution at 15mm and 20mm distal to mental foramen. Conclusion: Posterior mini implants placement resulted in improved denture support and minimal overdenture displacement. The functional load on posterior mini implants has a positive effect on preservation of the residual alveolar ridge. Wide mini implants distribution is an acceptable alternative prosthodontic design to four-interforaminal mini implants distribution when anatomical and economical factors permit.