OBJECTIVETo study the relationship between the mesiodistal tipping degree of maxillary and mandible posterior teeth and different vertical facial skeletal types of subjects with normal occlusion.

METHODS163 subjects with normal occlusion were selected, lateral cephalograms were taken and divided into three different facial skeletal types. The difference of the mesiodistal tipping degrees and intersection angles of upper and lower posterior teeth between the three different facial skeletal types were analyzed.

RESULTSAmong 163 subjects, vertical growth pattern, average growth pattern and horizontal growth pattern were 24, 96 and 43 respectively. There were statistic differences of mesiodistal tipping degrees of the first and second maxillary and mandible premolar and the first permanent molar between vertical growth and horizontal growth pattern, horizontal growth and average growth pattern (P < 0.05). But there were no statistically significant differences between vertical growth and average growth pattern (P > 0.05). The differences of the maxillary and mandible posterior teeth's intersection angle among three vertical facial skeletal types had no statistic significance (P > 0.05).

CONCLUSIONDifferent vertical facial skeletal type has its own normal and coordinated posterior teeth mesiodistal tipping degrees.

Dental Occlusion ; Humans ; Mandible ; anatomy & histology ; Maxilla ; anatomy & histology ; Tooth

Sagittal split ramus osteotomy (SSRO) is one of the surgical techniques used to correct mandibular deformities. In order to prevent many surgical anatomical problems, we observed the anatomical structures related to SSRO. In dry mandibles of Koreans, lingular tips were located somewhat posteriorly and superiorly on the mandibular ramus. On the coronal sections of mandible, the mean cortical width of facial cortex was increased toward the ramus region while the lingual cortex was thinnest in the ramus region. On the same sections, all the fusion points of the buccal and lingual cortical plate were located above the mandibular lingula and beneath the mandibular notch. So, performing the SSRO on Koreans, medial horizontal osteotomy should be done through the superior aspect of the mandibular lingula. The cut line is extended 5-8 mm posterior to the mandibular lingula to preserve sufficient cortical width to strengthen the involved osseous segments and reduce possible surgical complications.
Anatomy, Artistic ; Human ; Human ; Mandible/surgery* ; Mandible/anatomy & histology* ; Medical Illustration ; Osteotomy/methods*

OBJECTIVETo investigate the dental compensation in different sagittal jaw relationships.

METHODSOne hundred and fifty-seven post-treatment cases with satisfied outcome were chosen. Computerized cephalometric analysis was performed to evaluate the sagittal jaw relationship. Incisor torque were measured based on study models. Correlation analysis was performed.

RESULTSCompared with skeletal class I cases, the upper incisors of skeletal class III cases were more proclined, and lower incisors were more retroclined; the opposite result was found in skeletal class II cases. Dental compensation in class I cases took place primarily at lower incisors.

CONCLUSIONSIncisor torque control was important in patients with various sagittal jaw relationships.

Cephalometry ; Female ; Humans ; Incisor ; Male ; Malocclusion ; therapy ; Mandible ; anatomy & histology ; Maxilla ; anatomy & histology ; Orthodontics, Corrective ; Torque

OBJECTIVEThe purpose of this study was to investigate the center height of clinical crowns and the difference among individuals, together with the regularity of the Spee curve in mandible and compensating curve in maxilla for the people with normal occlusion in Chengdu area.

METHODSThe data were derived from systematically collected people with normal occlusion in Chengdu area, including 36 males and 39 females (ranged from 18 to 35 years). The values of center height of clinical crowns, the depths of Spee curve and curve formed by the center of clinical crowns in mandible were obtained by measurement. Afterwards, the distribution of the center height of clinical crowns was analyzed, as well as the depth of curve formed by the center of clinical crowns in mandible and its correlation with depth of Spee.

RESULTS(1) The distribution of the center height of clinical crowns accord with normal distribution and the standard deviation was minor(< 0.5 mm); (2) There was no statistical difference between male and female for the center height of clinical crowns; (3) The depth of curve formed by the center of clinical crowns in mandible and the depths of Spee curve showed highly correlation (gamma = 0.986, P < 0.0001).

CONCLUSION(1) The difference of the center height in clinical crowns among individuals with normal occlusion in Chengdu area was minor; (2) There was no significant difference on the center height in clinical crowns between male and female; (3) Provide a recommended bracket placement chart suitable for people of Chengdu area in clinical practice; (4) The brackets of the pre-adjusted appliance should be placed in the center of clinical crowns, despite some adjustment are needed in some special circumstances.

Adolescent ; Adult ; Anthropometry ; Dental Arch ; anatomy & histology ; Dental Occlusion ; Female ; Humans ; Male ; Mandible ; anatomy & histology ; Maxilla ; anatomy & histology ; Orthodontic Brackets ; Reference Values ; Tooth Crown ; anatomy & histology

OBJECTIVEThe aim of this study was to rebuild the anatomic structures of the mandibular bone and the canal, and to testify the reliability of the rebuilt model.

METHODS15 mandibular bones with teeth are chosen, and a three-dimensional model was built with the method of CT. The slices vertical to the compensating curve were made in every dental position. Then the authors collected the data of alveoli and mandibular canal in every slice. The same work was done to the bone specimen, and then comparative analysis was done.

RESULTSThe wideness of the alveoli and 10 mm bellow increased from mesial to distal position. It was the same of the alveoli from the top to the bottom. The mandibular canal lied in the inner and inferior side of the mandibular body. There was no significant difference in data collected with these two methods.

CONCLUSIONDifferent types of dental implants should be chosen according to the anatomic characteristic of the mandibular bone in every dental position before the operation to avoid complications. And a reliable, accurate and direct method of planning an implant operation is to rebuild a three-dimensional model.

Adult ; Computer Graphics ; Humans ; Mandible ; anatomy & histology ; diagnostic imaging ; innervation ; Mandibular Nerve ; anatomy & histology ; Models, Anatomic ; Tomography, Spiral Computed ; methods

OBJECTIVETo study the course and distribution of buccal and marginal mandibular branches of facial nerve, and its relevance to the treatment of facial paralysis and the protection of facial nerve during surgery.

METHODS12 cadaver heads were dissected (24 specimens). The course of the buccal and marginal mandibular branch and the interconnections between them were observed. The relationship of buccal branch to parotid duct, marginal mandibular branch to the inferior border of mandible were studied. With modified Sihler's staining technique, the distribution of facial nerve branches in innervated mimetic muscles was displayed. These anatomic relationships mentioned above were further confirmed during the operation of 40 patients with facial paralysis.

RESULTSParotid duct had a constant surface landmark. Buccal branch mainly consisted of 2-3 ramifications in 87.5% of the specimens, while marginal mandibular branch was double or single in 95.9% of the specimens. The buccal branch coursed within the distance between 10.7 mm above and 9.3 mm below the parotid duct, and innervated mimetic muscles of midface. The marginal mandibular branch coursed within the distance between 13.4 mm above and 4.8 mm below the lower border of mandible, crossed superiorly the facial artery and innervated mimetic muscles of lower lip.

CONCLUSIONSThere is a close relationship of buccal branch to parotid duct and marginal mandibular branch to facial artery and lower border of mandible. With modified Sihler's staining technique, the original 3-dimensional picture of the intramuscular nerve distribution in human mimetic muscles.

Adult ; Facial Nerve ; anatomy & histology ; Facial Paralysis ; surgery ; Female ; Humans ; In Vitro Techniques ; Male ; Mandible ; anatomy & histology ; innervation

OBJECTIVETo study applied anatomy of adult mandibular ramus and condyle.

METHODSObservation and measurement were made on 16 adult mandibular rami and condyles.

RESULTSThickness became gradually greater within 15 mm from the back edge of ramus. Some adult mandibular rami had no spongy bone at the level of 10 mm above mandibular foramen.

CONCLUSIONSThese date are very important for application of lag screw osteosynthesis in condylar fracture.

Adult ; Bone Screws ; Fracture Fixation, Internal ; Humans ; Mandible ; anatomy & histology ; Mandibular Condyle ; anatomy & histology ; Mandibular Fractures ; surgery

OBJECTIVETo study the anatomy of mandibular bone flap pedicled with temporal muscle for midfacial bone defects.

METHODSThe shape and blood supply of the temporal muscle and mandibular ramus, as well as their relationship, were observed and measured in 30 sides of adult head specimens.

RESULTSThe temporal muscle has a fan-shaped main portion, then is scattered into three bundles as anterolateral, anteromedial, posterior bundles, which end respectively at anterior border of ramus, the temporal ridge and posterior portion of coronoid process. Then the muscle goes downward until it reaches the distal side of the third medial surface molar and attaches the 3/4 of medial surface of anterior portion of ramus. The blood supply of temporal muscle includes the medial temporal artery with external diameter of (0.76 +/- 0.20) mm, the anterior deep temporal arteries with external diameter of (0.79 +/- 0.21) mm, posterior deep temporal arteries with external diameter of (0.98 +/- 0.64) mm, the accessory deep temporal artery formed by many little branches. The anterior part of ramus is supplied by the periosteal arteries and the bony perforator of the deep temporal arteries. Rectangular ramus of mandible was divided into anterior portion and posterior portion by the line linking the lowest point of mandibular notch, mandibular foramen and mandibular canal. Anterior portion can supply a bone flap with a size of (46.67 +/- 6.85) mm x (17.98 +/- 2.64) mm x (11.49 +/- 0.99) mm.

CONCLUSIONSThe mandibular bone flap pedicled with temporal muscle has a reliable blood supply and abundant bone volume. It is feasible to design a mandibular bone flap pedicled with temporal muscle for midfacial bone defect.

Adult ; Bone Transplantation ; Female ; Humans ; Male ; Mandible ; anatomy & histology ; surgery ; Surgical Flaps ; Temporal Muscle ; anatomy & histology ; blood supply ; innervation

It is a basic prerequisite for the successful completion of endodontic treatment to thoroughly understand the root canal space anatomy. With the development of dental devices in dentistry, the root canal morphology of the mandibular first premolars can be presented in more detail. Before conducting root canal therapy on the mandibular first premolar with complex root canal morphology, it should be necessary to evaluate the potential difficulties and risks for making an appropriate treatment plan. The present paper reviews the research progress on the diversities of root canal morphology in mandibular first premolars in recent years, and then makes technologic recommendations based on the morphology diversities.
Humans ; Dental Pulp Cavity/diagnostic imaging* ; Bicuspid/anatomy & histology* ; Mandible ; Tooth Root/anatomy & histology* ; Root Canal Therapy

OBJECTIVETo examine adaptive changes in the shape of the upper airway during titrated mandibular advancement. Furthermore, to understand the mechanism of mandible-adjustable therapy to improve the ventilation.

METHODSFourteen non-apnea participated in the study. A custom-made oral device was used to keep the mandible in titrated advancement at 0% (F0), 50% (F50), 75% (F75), 100% (F100) of the maximum advancement. Magnetic resonance imaging was used to investigate the difference in the shape of upper-airway in these 4 positions. Changes in the anteroposterior direction (AP), lateral direction (Lat) and its ratio (AP/Lat) were calculated, which were transformed into the percentage of the original ones.

RESULTSThe dose-dependent decrease of AP/Lat was found when the mandible was advanced (P = 0.0001). Lateral change rate in percentage increased by degrees (P = 0.0023), while the increase of anteroposterior change rate in percentage showed no statistical significance.

CONCLUSIONThe shape of upper airway tended to be less round. The enlargement of upper airway during titrated mandibular advancement was mainly the result of enlargement in lateral direction.

Asian Continental Ancestry Group ; Humans ; Magnetic Resonance Imaging ; Male ; Mandible ; anatomy & histology ; Mandibular Advancement ; Palate, Soft ; anatomy & histology ; Pharynx ; anatomy & histology