Age-related changes in the location of the mandibular and mental foramen in children with Mongoloid skeletal pattern

Skeletal maturation and the location of the mandibular foramen within the ramus mandibulae

PURPOSE

It is well documented that the mandible does not grow at a constant rate. There are significant correlations between the increase of mandibular size and cervical vertebral maturation. The peak growth velocity of the mandible occurs after the third stage of cervical vertebral maturation. The location of the mandibular foramen (MF) and its changes subsequent to growth are of great interest to clinicians as they relate to the anesthesia of the inferior alveolar nerve and to mandibular surgical procedures. Therefore, the aim of the present study was to assess the influence of the mandibular growth spurt on the location of the MF in various skeletal growth patterns.

METHODS

Panoramic and lateral cephalometric radiographs of 98 (32 orthognathic, 50 retrognathic, 16 prognathic) patients before and after the growth peak were collected. For each subject, the maturational stage of the cervical vertebrae was defined on successive lateral cephalograms and the vertical and horizontal position of the MF was evaluated on two panoramic radiographs, one before and one after the growth peak.

RESULTS

The MF-Post/MF-Ant ratio (MF distance to the posterior border of the ramus/MF distance to the anterior border of the ramus) significantly increased after the growth peak in orthognathic and retrognathic subjects (P = 0.015 and 0.02, respectively). This ratio did not significantly increase in prognathic subjects (P = 0.882). No statistically significant changes in the vertical position of the MF were found in the three groups after the growth spurt.

CONCLUSION

The horizontal position of the MF moves in an anterior direction in orthognathic and retrognathic subjects during the mandibular growth spurt. The vertical position of the mandibular foramen remains unchanged during this period.

Evaluating Sensory Nerve Outcomes After Horizontal Osteotomy for Mandibular Distraction in Infant Robin Sequence Patients

ABSTRACT

There has yet to be a consensus on the appropriate technique for mandibular distraction in the infant Pierre Robin population nor is their sufficient data on sensory nerve outcomes. The purpose of this study is to validate the safety of the horizontal osteotomy by: (1) determining mandibular foramen location in infant Pierre Robin patients relative to the dentoalveolar plane and (2) evaluate long-term function of the inferior alveolar nerve in previously distracted Pierre Robin patients. Preoperative 3D Computed tomography (CT) scans of Pierre Robin patients < 1 year old were reviewed. A line at the level of the mandibular dentoalveolar plane was drawn across the lingual surface of the ramus and the distance to the mandibular foramen was then measured. Semmes-Weinstein monofilaments of the lower lip and chin bilaterally was performed on mandibular distraction patients in clinic. Inclusion criteria was patients >6 years of age having undergone bilateral mandibular distraction at <1 year of age. Fifteen patients' CT studies were examined. The mandibular foramen was consistently below the level of the dentoalveolar plane at an average distance of 4.7 mm. Eight patients were included in the prospective arm. Average age was 12.2. All patients had normal sensation at 2.83 through all areas. The mandibular foramen reliably exists below the dentoalveolar plane. In addition, all patients reviewed postoperatively with >10 years of follow up demonstrated normative sensation. The horizontal corticotomy performed just above the mandibular dentoalveolar plane spares the inferior alveolar nerve in young Pierre Robin patients undergoing distraction.

Comparison of 0.5% Centbucridine and 2% Lignocaine as Local Anesthetic Agents for Dental Procedures in Children: A Randomised Controlled Trial

OBJECTIVE

To compare 0.5% centbucridine and 2% lignocaine (with adrenaline) as local anesthetic agents for dental treatment procedures in 12 to 14 y old children.

METHODS

A split mouth, triple blind randomised controlled trial design was adopted for this study. Fifty six children between 12 to 14 y of age requiring bilateral administration of inferior alveolar nerve block (IANB) were recruited for this study. The mandibular quadrants were randomly allotted to the drug being administered. Standardised protocol for local anesthesia administration was used. The primary outcomes assessed were onset, duration and depth of anesthesia using the pre-validated Visual Analog scale and effect on perioperative pulse rate using a pulse oximeter.

RESULTS

There was no significant difference between centbucridine and lignocaine with respect to their mean onset [(105.181 and 99.727 s respectively), (p = 0.647)], duration of action [(91.931 and 91.613 min respectively), (p = 0.931)] and depth of anesthesia at 10, 30 and 60 min. Centbucridine showed a statistically significant drop in the pulse rate at 10 (p < 0.001) and 30 min (p < 0.001).

CONCLUSIONS

There was no significant difference between 0.5% centbucridine and 2% lignocaine with respect to onset, duration and depth of anesthesia.

Measuring the Position of the Mandibular Foramen in Relation to the Dentoalveolar Plane in Pierre Robin Patients: Establishing Safety of the Horizontal Osteotomy

BACKGROUND

Mandibular distraction with horizontal osteotomy of the ramus and vertical distraction vector has successfully treated airway obstruction in young Pierre Robin patients. Placing the osteotomy just above the dentoalveolar plane can minimize damage to the inferior alveolar nerve. This study maps the position of the mandibular foramen relative to the height of the dentoalveolar plane to demonstrate the safety of this technique in Pierre Robin neonates.

METHODS

Retrospective review of 3D CT scans of Pierre Robin patients was performed with inclusion criteria: ≤1 year of age, bilateral micrognathia requiring surgical intervention for airway (ie, tracheostomy versus mandibular distraction), no prior mandible surgery, and pre-operative 3D CT study. Demographic information collected included: age at CT scan, age at surgery, and genetic diagnosis. Using the 3D study of each patient's right mandible, a line at the level of the mandibular dentoalveolar plane was drawn across the lingual surface of the ramus and the distance to the mandibular foramen at a length perpendicular to the dentoalveolar plane line was then measured.

RESULTS

Fifteen patients were included in the study (at least 9 Pierre Robin). Average age at time of CT scan was 71.4 days old. The mandibular foramen was below the level of the dentoalveolar plane in all cases at an average distance of 4.7 mm. Average ramus height 46.2±13.4 CONCLUSIONS:: The dentoalveolar plane was consistently above the mandibular foramen in all patients. Thus, the horizontal corticotomy at a level just above the mandibular dentoalveolar plane spares the inferior alveolar nerve in neonatal Pierre Robin patients undergoing vertical vector mandibular distraction.

The mandibular plane: a stable reference to localize the mandibular foramen, even during growth

Objectives

The location of the mandibular foramen is essential for the quality of the inferior alveolar nerve block anaesthesia and has often been studied with contradictory results over the years. The aim of this study was to locate the mandibular foramen, according to the dental age of the subject, through 3D analysis.

Methods

Three-dimensional images were reconstructed from mandibular computed tomography of 260 children, adolescents and adults. The occlusal plane was determined as the average plane passing through the buccal cusps of mandibular molars, premolars, and canines, and through the incisor edge. The mandibular foramen was located three dimensionally in relation to the anterior edge of the ramus (or coronoid notch), the sagittal plane and the occlusal plane.

Results

All along mandibular growth, the three distances defining the relative position of the mandibular foramen showed negligible changes. The mandibular foramen is located from − 0.4 to 2.9 mm above the occlusal plane. The distance between the mandibular foramen and the leading edge of the mandibular ramus ranged from 17 to 19.5 mm. The angle between the ramus and the sagittal plane ranged from 3° to 5.4°.

Conclusion

In our sample, and using the occlusal plane and the anterior edge of the ramus as anatomical references, the location of the mandibular foramen was considered to be similar in all patients regardless of age.

CBCT Assessment of Mental Foramen Position Relative to Anatomical Landmarks

Purpose. This study was carried out on an Iranian population aiming to investigate mental foramen position relative to inferior border of mandible and skeletal midline and its gender and age differences on CBCT projections. Materials and Methods. A number of 180 CBCT images of patients were analyzed in different planes (tangential, cross-sectional, and axial). The distances from the superior border of mental foramen to the inferior border of mandible and from the anterior border of mental foramen to the midline were calculated. Results. The mean distance from mental foramen to the inferior border of mandible in the right side was 13.26 mm (SD ± 2.34) and in the left side was 13.37 mm (SD ± 2.19). There was a statistically significant difference between genders in terms of the distance between mental foramen and inferior border of mandible (P value = 0.000). The mean distances from mental foramen to midline were 25.86 mm (SD ± 0.27) and 25.53 mm (SD ± 0.31) in the right and left sides, respectively. Conclusions. The vertical and horizontal positions of mental foramen can be determined from stable anatomical landmarks such as mandibular inferior border and skeletal midline in both dentulous and edentulous patients. The distance from the superior border of mental foramen to the inferior border of mandible exhibited sexual dimorphism.