Incisive Nerve Research Articles

Integrative approach for supernumerary teeth: a single-center retrospective analysis.

This study aimed to provide a comprehensive case analysis from a single center, with the objective of clarifying the optimal timing and recommendations for a preferred treatment strategy customized to the specific presentation of each type of supernumerary tooth identified in the research. A retrospective study was conducted on patients who presented with a supernumerary tooth and were treated interdisciplinarily at the clinic. In total, 55 patients with 81 supernumerary teeth of the permanent dentition were analyzed, 30 males and 25 females. The dentition status of the patients was as follows: 31 patients with mixed dentition, no patients with primary dentition, and 24 patients with permanent dentition. The diagnosis of supernumerary tooth was primarily made by general or pediatric dental practitioners and/or orthodontists. Patients were then referred to maxillofacial surgeons for treatment decision. The timing of treatment was mainly determined by the oral surgeon, based on the recommendations of the other specialists involved. Cases involving maleruption or malalignment of permanent teeth required both surgical and orthodontic treatment. Patients over 9 years old were treated either under local anesthesia or sedation, whereas those under 9 years old were treated under deep sedation or general anesthesia. A comprehensive investigation of cases involved the utilization of CBCT at the supernumerary tooth site to facilitate treatment planning. There was a significant correlation between younger age and the preference for treatment under sedation or general anesthesia (P = .01, t test). Similarly, a strong association was found between younger age and the need for additional orthodontic treatment (P = .016, t test). Cases of surgical removal of a supernumerary tooth at a young age typically did not require orthodontic traction of the permanent tooth, in contrast to cases of late surgical intervention (patients over 11 years old), which often did necessitate such traction. There was a strong tendency for treating supernumerary teeth in the maxilla. The proximity of supernumerary teeth to vital anatomical landmarks significantly influenced treatment decisions. Patients with supernumerary teeth near the mental foramen or the inferior dental canal in the premolar area were exclusively placed under follow-up care (P = .002, Pearson chi-square test). However, in the maxilla, the proximity of supernumerary teeth to vital structures such as the floor of the nose and the incisive nerve did not affect the treatment approach, and those supernumerary teeth were mostly removed. A team approach for managing supernumerary teeth is recommended. The timing of treatment should carefully consider the advantages and disadvantages of early versus late intervention. Early surgical treatment in cases where eruption is disturbed might result in spontaneous eruption, eliminating the need for orthodontic traction of the permanent teeth.

ANATOMICAL VARIABILITY OF THE SEGMENTS OF THE INFERIOR ALVEOLAR NERVE IN THE PEOPLE OF SECOND PERIOD OF MATURE AND OLDER AGE

To avoid complications of bicortical implantation, great importance is attached to the study of individual morphological features of the mandible and its structures, in particular, the anatomical variability of the inferior alveolar nerve (IAN) and mandibular canal. The purpose of the study was to fi nd out the peculiarities of the structure, topography and individual anatomical variability of the IAN in persons of the second period of maturity and older age. Cone-beam computer tomography of 54 people of both sexes aged 45-65 years with three- dimensional reconstruction, morphometry and statistical analysis was studied. On the basis of our own research on the topographical and anatomical features of the IAN and its syntopy with the mandible, in particular, with the mandibular canal, we propose to distinguish 4 of its divisions: extra- canal – from the place of formation to the entrance to the mandibular canal; intracanal – from the mandibular foramen to the mental foramen; mental – after exiting the mandibular canal; incisive – after the departure of the mental branch. The topographical and anatomical features and anatomical variability of the IAN were studied. In people of the second period of mature and elderly age, anatomical variability of the macroscopic structure and topography of the IAN was established, which manifested itself in high (4.0-11.0 mm) and low (22.0-33.0 mm) levels, relative to the foramen ovale its beginning and form (one or two trunks) of departure from the mandibular nerve. The largest number of nerve connections with other branches of the mandibular nerve is formed by the extracanal section of the IAN: with the auriculo-t emporal nerve (29 cases – 53.7 %), with the lingual nerve (5 cases – 9.26 %), with the nerve of the medial pterygoid muscle (3 observations – 5.56 %) and with the nerve of the lateral pterygoid muscle (2 specimens – 3.7 %). A diff erent level of departure of the nerve to mylohyoid from the extracanal section of the IAN was established: high (5.0-7.0 mm) and low (27.0-31.0 mm). Anatomical variability of the intracanal part of the IAN was manifested by structural variants: a single trunk (43 cases, 79.6 %), rarely – two trunks (11 observations, 20.4 %) and very rarely – the lower dental plexus (6 specimens, 11,11 %). The proximity of the roots of the 7th and 8th teeth to the IAN can be the cause of severe pain in the pathology of these teeth and cause nerve damage during their removal. Nerve connections occur between the right and left incisive nerves, the knowledge of which is an important practical value for performing anesthesia of the front row of teeth. The number of branches to the teeth, interalveolar septa and gingiva from the IAN signifi cantly decreases with age and with a violation of the integrity of the dentition.

A Retrospective Study of Location, Dimension, and Prevalence of Mandibular Incisive Nerve Canal with the Help of Cone-Beam Computed Tomography (CBCT).

To evaluate the mandibular incisive nerve canal's prevalence, location, and size. To ascertain the frequency, relationship to surrounding critical structures, and variance in the size and position of the mandibular incisive nerve canal. Mandibular incisive canal (MIC) measurements, locations, and prevalence were noted in 80 patients' cone-beam computed tomography (CBCT), ranging in age from 18 to 80. The overall incidence of missing canals was found to be 30% on the right side, 33.75% on the left, and 23.75% on both sides. Conclusion: In summary, magnetic resonance imaging (MRI) (3 Tesla) and other higher-resolution imaging modalities should be compared with CBCT for accurate MIC measurement and location assessment.

The Anatomy of the Mandibular Incisive Canal and Its Influence in Implant Therapy: A Scoping Review.

The interforaminal region is considered more favorable for implant placement than the posterior mandible in edentulous patients, mainly because the inferior alveolar nerve can interfere with implant placement in the severely resorbed posterior mandible. However, complications in the interforaminal region may occur due to the presence of the mandibular incisive nerve. This scoping review aims to describe the mandibular incisive nerve anatomy related to the potential interference in implant therapy. A comprehensive literature search was conducted in the following databases: MEDLINE (via PubMed), Web of Science, and Scopus. This scoping review was structured according to the Joanna Briggs Institute method. Thirteen studies were included in the review. All of the studies were observational cohort anatomical studies, carried out mainly by CBCT and on cadavers. A total of 1,471 patients/cadavers were studied. The mandibular incisive nerve was present in 87% to 100% of cases, with an average length of 9.97 mm and an average diameter of 1.97 mm. The mandibular incisive nerve may be damaged during drilling and implant placement, especially when using implant lengths > 12 mm. Damage to the mandibular incisive nerve due to implant placement could be present, but it is necessary to conduct more studies focusing on assessing mandibular incisive nerve damage to understand the clinical relevance of this nerve and its associated morbidities, such as neurosensorial alterations. Due to the different anatomical characteristics of this nerve, CBCT analysis is recommended for implant therapy in the anterior mandible to prevent the described complications.

Assessment of Anterior Loop of Inferior Alveolar Nerve – A Cone Beam Computed Tomography Study

Introduction: The anterior loop (AL) of the inferior alveolar nerve (IAN) and the mental foramen (MF) are important anatomical structures that should be taken into consideration during preoperative planning in the anterior mandibular region. This study aims to assess the prevalence, length, and type of the AL of the IAN in males and females in a South Indian population. Additionally, the distance from the MF to the lower border of the mandible is assessed. Materials and Methods: A total of 115 cone-beam computed tomography (CBCT) scans of 230 sides of mandibles were taken using a Carestream Select CS9300 CBCT machine (Carestream Dental LLC, Atlanta, USA). The scans were selected from archives and divided into three different age groups (<40, 41–60, >61 years). The scans were analyzed to detect the canal of the AL of the inferior alveolar nerve canal (IANC). The IANC, along with the AL canal and part of the incisive nerve canal, was traced using the CS 9300 software. The length of the mandibular nerve was measured for each patient in cross-sectional and panoramic views. Results: The AL was present in 92.6% of the 115 participants. Overall anterior loop length ranged between 0.9 and 15.2 mm. The mean length of AL in panoramic view on the right side was 3.284 ± 2.314 mm and it was 3.015 ± 2151 mm on the left side. Y-shaped AL was more predominant when compared to T-shaped AL in the sample. Conclusion: The prevalence of AL was relatively higher in subjects ranging from 41 to 60 years with a slight increase in female predominance.

Needle-free Mental Incisive Nerve Block:In vitro, Cadaveric, and Pilot Clinical Studies

The present study aimed to optimize Needle-Free Liquid Jet Injection (NFLJI) for Mental Incisive Nerve Blocks (MINB) and evaluate its clinical safety and feasibility. A MINB protocol was developed and optimized by series of NFLJI experiments in soft tissue phantoms and cadavers, then validated in two pilot Randomized Controlled Trials (RCT). The NFLJI penetration depth was found to be directly proportional to the supply pressure and volume. High-pressure NFLJIs (620 kPa or above) created maximum force and total work significantly greater than needle injections. Low-pressure NFLJIs (413 kPa), however, produced results similar to those of needle injections. Additionally, high-pressure NFLJIs created jet impingement pressure and maximum jet penetration pressure higher than low-pressure NFLJIs. Pilot RCTs revealed that high-pressure NFLJI caused a high risk of discomfort (60%) and paresthesia (20%); meanwhile, low-pressure NFLJI was less likely to cause complications (0%). The preliminary success rates of MINB from cadavers using NFLJIs and needles were 83.3% and 87.5%. In comparison, those from RCTs are 60% and 70%, respectively. To conclude, NFLJI supply pressure can be adjusted to achieve effective MINB with minimal complications. Furthermore, the cadaver study and pilot RCTs confirmed the feasibility for further non-inferiority RCT.

Septoplasties are unlikely to cause postoperative numbness of the anterior palate.

Septoplasties and septorhinoplasties are very commonly performed surgical procedures in modern aesthetic and functional medicine. Throughout the surgery, close manipulation to the incisive nerves' course is being executed. This retrospective analysis followed up on potential sensitivity disorders of the anterior palate due to nerve damage. This retrospective review of 2000patients' charts, who had undergone the procedure of aseptoplasty or septorhinoplasty between June 2013 and January 2019 was conducted at the Department of General Otorhinolaryngology, Medical University of Graz. Medical records of all included patients were reviewed with special attention to postoperative numbness of the anterior palate. Among the 2000 included patients, aseptoplasty was performed in 48% (n = 955), aseptorhinoplasty in 35% (n = 703) and aseptoplasty in combination with afunctional endoscopic sinus surgery in 17% (n = 342). In total, 86% (n = 1721) showed no complications at all during the follow-up period. In 0.25% (n = 5) asensitivity disorder of the anterior palate occurred. Of the five cases with apostoperative numbness of the anterior palate four occurred after aseptoplasty and the fifth occurred following aseptorhinoplasty. At this current time, this is the largest study investigating postoperative numbness of the anterior palate retracing septoplasty or septorhinoplasty. As aresult, the currently used techniques for the operations do not pose arisk for the incisive nerve despite close surgical manipulation to the nerves' course. Nevertheless, patients should be informed and educated about the possibility of an occurring sensitivity disorder regarding the anterior palate during informed consent.

Bilateral mental incisive nerve block probably has a higher success rate than unilateral mental incisive nerve block in mandibular incisors with irreversible pulpitis

Kumar U, Aggarwal V, Singh S, Singh SP, Gauba K. Is bilateral mental incisive nerve block better than unilateral mental incisive nerve block during the endodontic management of mandibular incisors with symptomatic irreversible pulpitis? A prospective single-blind randomized clinical trial [published online ahead of print February 20, 2020]. J Endod. https://doi.org/10.1016/j.joen.2020.01.008.

The mandibular incisive foramen, a false mental foramen

The mandibular incisive foramen (MIF) is an opening on the external surface of the dentate mandibular body, medial to, and facing the mental foramen (MF). There is actually scarce evidence of such MIF. A retrospective Cone Beam CT (CBCT) study of the archived files of a 56 y.o. male patient was documented anatomically for dental medical purposes. In the 2nd premolar region of the left hemimandible were found two adjacent foramina facing one each other: the distal one was opened medially, while the medial one was oriented distally. On axial CBCT slices the mandibular canal was detected to open at the distal foramen in the outer cortical plate of the mandible. The medial foramen in that cortical plate served as entrance to the mandibular incisive canal, thus being a MIF. CBCT accurately distinguishes the canals opening on the outer cortical plate of the mandible thus is of use to differentiate a MIF from a MF. Such adjacent foramina expose at risk not just the mental nerve, as in cases with true multiple MF, but also the IAN and the mandibular incisive nerve.

Is Bilateral Mental Incisive Nerve Block Better than Unilateral Mental Incisive Nerve Block during the Endodontic Management of Mandibular Incisors with Symptomatic Irreversible Pulpitis? A Prospective Single-blind Randomized Clinical Trial

IntroductionThe purpose of this clinical trial was to comparatively evaluate the anesthetic efficacy of unilateral and bilateral mental incisive nerve block (MINB) during the endodontic treatment of inflamed mandibular incisors. MethodsThe study was designed as a crossover single-blind study. A total of 76 patients requiring endodontic intervention in at least 2 mandibular incisors participated in this trial. The patients randomly received unilateral or bilateral MINB of 1.8 mL of 2% lidocaine with 1:80,000 epinephrine at 2 separate appointments. To blind the procedure, a saline injection was given on the contralateral side in the unilateral injections. The endodontic procedure was initiated in the incisors on the side of the first anesthetic injection. Patients with a negative response to electric testing received endodontic access opening under rubber dam. Patients were asked to report pain, if any, during the endodontic procedure by using a Heft-Parker visual analog scale. The anesthetic success was defined as no or mild pain on Heft-Parker visual analog scale (score, 0–54). The statistical analysis was performed with McNemar tests at P values <.05. ResultsThe success rates of unilateral MINB and bilateral MINB were 38% and 64%, respectively, for the central incisors and 44% and 69%, respectively, for the lateral incisors. The difference was statistically significant (P < .05). ConclusionsThe bilateral MINB was more successful during the endodontic management of mandibular incisors with inflamed pulps. However, both the techniques failed to give 100% success rates.

Evaluation of the effect of the inversion filter on enhancing the visibility of the mandibular incisive canal in comparison with the original images.

The mandibular incisive canal (MIC) is a neural canal containing one of the lower branches of the inferior alveolar nerve, called the mandibular incisive nerve, which can get damaged and cause complications during the removal of bone from the interforaminal region. The aim of this study was to determine the effect of the inversion filter (IF) on improving the visibility of MIC as compared to the original images. In this retrospective, descriptive, analytical study, 343 samples of digital panoramic radiography were examined. The images were analyzed with and without IF. The frequency and confidence intervals (CIs) of identifying MIC were used to determine its visibility, both with IF and in the original images. Besides, the difference between the maximum and minimum diameters of the canal as well as the distance from MIC to the alveolar crest and to the mental foramen were examined. For statistical analysis, McNemar's test and the paired t-test were used, and the concordance was calculated using the kappa coefficient. No significant differences were found in the prevalence of the incisive canal, or in its unilateral or bilateral visibility between the original and filtered radiography in this study (p = 0.42 and p = 0.67, respectively). The absolute values of the interval difference between MIC and the mental foramen, the maximum and minimum diameters of MIC, and the distance from MIC to the alveolar crest were statistically significant between the filtered and original radiography, although the difference was clinically unimportant. The use of IF produced results similar to the original radiography; its application neither increased the clarity nor improved the visibility of the incisive canal.

Assessment of prevalence and position of mandibular incisive canal: A cone beam computed tomography study.

Objectives:To avoid anatomical and functional damage to mandibular interforaminal region during surgeries, it is necessary to detect the existence of mandibular incisive canal (MIC) and its proximity to adjacent structures. This study was aimed to evaluate the prevalence of MIC and its proximity to adjacent structures among Indian population.Materials and Methods:The images of 80 subjects with the age range of 20–60 years who had undergone cone beam computed tomography examination of the mandible were retrieved from the archival records. There was equal distribution of males and females.Results:The prevalence of MIC in the current study sample was found to be 43.89% with a slightly higher prevalence on left side as compared to right side, and higher prevalence among females as compared to males. Among different age groups, there was an increased incidence in the age group of >50 years. The distance of MIC from labial and lingual cortical plates and lower border of mandible were 4.338 ± 1.478 mm, 4.34 ± 1.53 mm and 9.417 ± 1.832 mm respectively.Conclusions:To conclude, the prevalence of MIC among Indian population was lower as compared to the prevalence among other populations. There were variations in prevalence in terms of age, gender and laterality, which could be used as a reference for further studies conducted on larger sample size. Mapping the incisive nerve canal will enable oral radiologists, to plan safely and negotiate the interforaminal region.

Anatomical features of mandibular incisive canal according to CBCT-data in patients in edentulous anterior mandibula (literature review)

Dental implant placement in the anterior mandibula can lead to the range of complications including neurological disorders and bleeding. One of the reasons is mandibular incisive nerve damage that carries homonymous neurovascular bundle. The aim of the study is the review of CBCT-studies of mandibular incisive canal in patients in edentulous anterior mandibula.

Imaging Aspects of the Mandibular Incisive Canal: A PROSPERO-Registered Systematic Review and Meta-Analysis of Cone Beam Computed Tomography Studies

This study aimed to perform a systematic review and meta-analysis of the literature on the mandibular incisive canal (MIC) studies using cone beam computed tomography (CBCT). A PROSPERO-registered systematic review (#42017056619) was conducted following the PRISMA statements to summarize current knowledge on the CBCT aspects of the MIC. A search was performed in PubMed's Medline and Scopus databases, without date or language restrictions, using the algorithm {[(Interforaminal region) OR (mandibular incisive channel) OR (mandibular incisive nerve) OR (mental mandible) OR (anterior mandible) (cone beam computed tomography). Also, the references were crosschecked. The Meta-Analysis of Statistics Assessment and Review Instrument and meta-analysis was used to evaluate the selected studies. A total of 410 articles were found, and 25 studies were selected after a two-step selection process. The CBCT systems differed regarding field of view (FOV) (large, n = 3; medium, n = 2; small, n = 4; not informed, n = 16) and voxel size (0.15 to 0.4 mm). Geographically, the studies were distributed across four continents (South America, North America, Asia, and Europe), and there was a statistical significance of studies from the American and Asian continents (P < .0001). From 3,421 CBCT exams, the number of female patients was slightly higher than male, and the mean age ranged from 29.8 to 59.1 years. The overall mean prevalence of MIC was 89.6% ± 15.08%, and bilateral occurrence was statistically significant (P < .0001). The studies using a voxel size lower than 0.3 mm showed the highest mean prevalence (93.88%) in comparison with voxel size described as ≥ 0.3 mm (89.33%). Diameter (0.45 to 4.12 mm) and length (6.6 to 40.3 mm) showed great variability among the included studies. In summary, the results of this systematic review evidenced a high worldwide prevalence of MIC. There was no prevalence of MIC in relation to sex, and its presence was mainly related to adults between the fourth and sixth decades of life. In addition, great heterogeneity of methodologies was observed.

Is Hypoesthesia in Mental and Incisive Nerves Areas A Complication of Inferior Alveolar Nerve Block or/and Wisdom Tooth Odontectomy?

Is Hypoesthesia in Mental and Incisive Nerves Areas A Complication of Inferior Alveolar Nerve Block or/and Wisdom Tooth Odontectomy?

Measuring anterior loop length of the inferior alveolar nerve to estimate safe zone in implant planning: A CBCT study in a Malaysian population

Statement of problemThe inferior alveolar nerve (IAN) frequently loops backward before exiting from the mental foramen and spreads several millimeters medially to the foramen. Implant placement in this area may damage the nerve if the anterior loop area is not carefully identified in a radiographic or computed tomography (CT) evaluation. PurposeThe purpose of this observational study was to measure the prevalence of the presence of the anterior loop and to estimate sex and ethnicity-related variations in anterior loop length in the Malaysian population. Material and methodsA total of 100 cone beam computed tomography (CBCT) Digital Imaging and Communications in Medicine (DICOM) files were selected from a pool of 810 ongoing or completed patients in 3 different ethnic groups: Malay (33), Indian (33), and Chinese (34). The DICOM data were imported into commercial software. The IAN was traced with software along with the anterior loop and part of the incisive nerve. The vertical length of the nerve was estimated from the canal to the opening of the mental foramen from the cross-sectional view and translated to the panoramic view. Measurement was made from this point to the most anterior point of the anterior loop by following the trajectory of the nerve and was repeated on the opposite side. A 2-way mixed analysis of variance (ANOVA) test was carried out to evaluate the sex- and ethnicity-related variations (α=.05). ResultsThe anterior loop was present in 94% of the 100 participants. Overall anterior loop length (AnLL) ranged between 0.73 and 7.99 mm with a mean length of 3.69 ±1.75 mm on the left side and 3.85 ±1.73 mm on the right side. Among all participants, no statistically significant differences were found between the left and right sides of the mandible (P=.379). Overall, no significant main effect of ethnicity (P=.869) or sex (P=.576) was found on AnLL measurements. Also, with multiple comparisons, no significant effect was found between each pair of ethnic groups. Men in all 3 ethnic groups had greater AnLL than women. ConclusionsThe anterior loop was present in 94% of the 100 participants among the 3 major ethnic groups of Malaysia. Overall AnLL ranged between 0.73 and 7.99 mm and mean lengths of 3.69 ±1.75 mm on the left side and 3.85 ±1.73 mm on the right side, with no significant ethnicity- or sex-related variations.

Efficacy and evaluation of cone beam computed tomography in determining the prevalence and length of anterior loop of inferior alveolar nerve in North Indian population

Introduction: The section of the inferior alveolar nerve (IAN) in front of the mental foramen and just before its ramification to the incisive nerve is known as anterior loop (AL) of IAN. Surgeries in the area of the anterior mandible may violate the AL resulting in neurosensory disturbances. Cone beam computed tomography (CBCT) is a new imaging modality that provides a multidimensional view of the facial skeleton. Aim: To evaluate the efficacy of CBCT in measuring the anterior looping of IAN. Objectives: To determine the prevalence of AL of IAN using CBCT, and to determine AL length using CBCT. Materials and Methods: Out of the total 1075 reported patients, 193 study participants fulfilling the inclusion criteria constituted the sample size were assessed for estimating the prevalence and determining the length of AL of IAN. They were scanned with a suitable digital imaging system for a variety of clinical indications using appropriate Dental Imaging Software. Results: The prevalence of anterior looping was found to be 37.3% and was highest (43.5%) in the age group of 36–56 years and was found to be statistically significant. The mean length of anterior looping was found to be 3.661 mm (SD ± 1.9933) with a maximum loop length of 8.8 mm. Conclusion: CBCT provides an accurate means to determine the anterior looping of IAN, measures its length, and thereby, helps in preoperative surgical planning.

Topography of the inferior alveolar nerve in human embryos and fetuses. An histomorphological study.

Abstract: The aim of this study is to establish the position of the inferior alveolar nerve in relation to the Meckel’s cartilage, the anlage of the mandibular body and primordia of the teeth, and also to trace the change in nerve trunk structure in the human prenatal ontogenesis. Serial sections (20µm) from thirty-two 6-12 weeks-old entire human embryos and serial sections (10µm) of six mandibles of 13-20 weeks-old human fetuses without developmental abnormalities were studied. Histological sections were impregnated with silver nitrate according to Bilshovsky-Buke and stained with hematoxylin and eosin. During embryonic development, the number of branches of the inferior alveolar nerve increases and its fascicular structure changes. In conclusion, the architecture of intraosseous canals in the body of the mandible, as well as the location of the foramina, is predetermined by the course and pattern of the vessel/nerve branching in the mandibular arch, even before the formation of bony trabeculae. Particularly, the formation of the incisive canal of the mandible can be explained by the presence of the incisive nerve as the extension of the inferior alveolar nerve. It has also been established that Meckel’s cartilage does not participate in mandibular canal morphogenesis.

A radiographic analysis of anatomical variation at the mandibular sites of intraoral bone harvesting

AbstractObjectivesIntraoral bone grafting is an important component of implant treatment, but also a source of intra‐ and post‐operative complications. This study sought to determine the relationship of bone surface to underlying nerves and vasculature, at the two most commonly employed intraoral sites for bone harvesting.Materials and MethodsData were collected by direct measurement of 103 potential graft sites (50 retromolar sites: 53 symphyseal sites) of patients undergoing CT scanning for implant surgery assessment.ResultsSymphyseal analysis included 26 female and 27 male patients. Data recorded were as follows: maximal width of the mandible between lower central incisor root tips (mean: 13.7 mm; range: 11.3–16.4 mm), maximal width of the mandible below the canine tip (mean: 11.5 mm; range: 7.7–14.9 mm), tip of canine to mandibular incisive nerve (mean: 4.3 mm; range: 1.2–8.9 mm), canine root tip to outer labial cortex (mean: 4.0 mm; range: 1.9–7.3 mm) and midline distance from the incisive nerve to outer labial cortex (mean: 3.0 mm; range: 1.0–6.9 mm). Retromolar analysis comprised of 33 female and 17 male patients. Data recorded included distance from inferior dental canal to the outer buccal cortex (mean: 3.2 mm; range: 1.0–7.9 mm), the most buccal point of the lower second molar roots to the outer buccal cortex (mean: 3.3 mm; range: 1.0–6.5 mm) and thickness of the mandibular crest at the lower second molar (mean: 13.8; range: 10.2–18.2 mm).ConclusionsThe proximity of underlying vital structures may be easily overlooked in routine examination of implant patients and may be related to patient characteristics.

A Prospective Study of Chin Bone Graft Harvesting for Unilateral Maxillary Alveolar Cleft During Mixed Dentition

The chin is a common donor site for alveolar cleft bone grafting. The amount of bone available at this site can be limited, because conservative harvesting with mixed dentition must consider the incisive nerve, the unerupted mandibular canine, and the integrity of the inferior mandibular border. Patients with nonsyndromic unilateral alveolar cleft in the mixed dentition stage were selected for this study. The volume of bone obtained from the mandibular symphysis (symphysis menti), degree of alteration in lower lip sensation, anterior tooth vitality, remaining bone in the alveolar cleft, and bone defects at the donor site 1year after surgery were evaluated. Eighteen patients were enrolled in this study. The mean volume of bone harvested from the symphysis was 2.1mL (range, 1.6 to 2.3mL). For all cases, the bone volume harvested from the symphysis was insufficient to fill the alveolar cleft defect, and allograft had to be added to completely fill the cleft. Allograft was admixed in the range of 0.5 to 1mL with autogenous bone harvested from the mandible. Lower lip sensation and vitality of the anterior teeth of the mandible were within the normal range 1year after surgery in all cases. Fourteen of 18 patients (77.8%) had normal bone height or bone height at least three fourths of the expected height in the grafted alveolar cleft after 1year; only 10% of the defect remained in the mandible. The amount of bone yielded by conservative monocortical bone harvest from the mandibular symphysis during the mixed dentition stage for unilateral alveolar cleft bone grafting is not sufficient in volume and should be mixed with allograft. However, donor site morbidity is low with this approach.