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

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

OBJECTIVETo investigate prevalence, location, negotiation and the effect of operating microscope (OM) in the treatment of the second mesiobuccal canal (MB2) in maxillary molars.

METHODS113 maxillary molars were studied. The crowns of the teeth were removed 1 mm above the chamber bottom for searching MB2 canal. Initially location and negotiation of MB2 canal were attempted without OM. Teeth in which MB2 canal were not located or negotiated were further explored under OM. Canal orifices including MB orifice, MB2 orifice and palatal orifice were filled by red gutta-percha cones, then the teeth were scanned by scanner. The images were analyzed by Image-Proplus 4.0 software to measure the relationship between MB2 canal and other canals.

RESULTSThe MB-MB2 distance is (1.47 +/- 0.54) mm, MB-P distance is (5.77 +/- 0.66) mm, the vertical distance from MB2 to MB-P line is (0.53 +/- 0.28) mm, the angle between MB-P line and MB-MB2 line is 23.07 degrees +/- 13.08 degrees. MB2 orifices were located in 70 teeth (61.9%) and negotiated in 53 teeth (46.9%) without OM. With OM, additional MB2 orifices were located in other 6 teeth, 4 were negotiated; and 2 were negotiated in which MB2 canal were not negotiated without OM.

CONCLUSIONSMB2 canal can be located in 67.3% and negotiated in 52.2% of maxillary molars. Ability to locate and negotiate MB2 canal is facilitated by OM. The MB2 canal was located less than 1 mm mesially to the MB-P line and 2 mm palatally from the MB orifice.

Dental Pulp Cavity ; anatomy & histology ; Humans ; Maxilla ; Microscopy ; Molar ; anatomy & histology

Objective: To explore the relationship between the width ratios of maxillary anterior teeth, the width/height ratios of maxillary central incisor and the esthetic proportions among individual normal occlusion, and to provide reference for the esthetic design of anterior teeth. Methods: A total of 300 Shanxi Medical University students who were residents from Shanxi province with normal occlusion (110 males, 190 females, aged 18-30 years) were recruited in this study from October 2020 to March 2021. Standardized digital photographs of the maxillary anterior tooth in natural head position were obtained, the perceived width of the maxillary anterior teeth (maxillary central incisors, lateral incisors and canines) on the left and right sides and height of maxillary central incisor were measured on the standardized digital photographs, then the width ratios of adjacent maxillary anterior teeth including the lateral incisor/central incisor width ratio (LI∶CI), the canine/lateral incisor width ratio (C∶LI), and the width/height ratios (W/H ratio) of the maxillary central incisor were calculated. The independent sample t test was used to compare the sex differences of each measurement project, Single sample t test was used to compare the difference of adjacent maxillary anterior teeth width ratios with golden proportion (0.618 and 0.618), Preston proportion (0.66 and 0.84), the recurring esthetic dental (RED) proportion (0.70 and 0.70). The percentage of anterior tooth width/intercanine width was calculated, the number and proportion of teeth conforming to golden percentage (25%, 15%, 10%)±1% or modified golden percentage (22.5%, 15.0%, 12.5%)±1% were calculated. The number and proportion of width/height ratio of maxillary central incisor ranged from 0.75 to 0.85 was counted. Results: The widths of maxillary central incisor, lateral incisor and canine were (8.50±0.52), (6.23±0.53) and (5.18±0.55) mm, respectively, the corresponding tooth of male [(8.74±0.49), (6.37±0.52), (5.41±0.47) mm] was significantly higher than that of female [(8.37±0.50), (6.15±0.52), (5.04±0.54) mm] (t=6.40, 3.55, 6.23,P<0.05). The width ratio of maxillary lateral incisor/central incisor was 0.73±0.05, and there was no significant difference between genders (t=-1.06, P>0.05). The width ratio of canine/lateral incisor was 0.84±0.10, and it was significantly higher in male (0.85±0.10) than in female (0.82±0.10) (t=2.42, P<0.05). Two width ratios of maxillary anterior teeth were significantly different from golden proportion and the RED proportion (t=38.50, 35.74, 11.48, 22.20, P<0.05). The lateral incisor/central incisor was significantly different from that of Preston proportion (t=24.66, P<0.05), while the canine/lateral incisor was not significantly different from that of Preston proportion (t=-0.92, P>0.05). In this study, a total of 0% (0/600) of central incisors, 63.0% (378/600) of lateral incisors and 5.8% (35/600) of canines met the golden percentage±1%. There were 42.8% (257/600) of central incisors, 63.0% (378/600) of lateral incisors and 56.7% (340/600) of canines met the modified golden percentage±1%. The width/height ratio of maxillary central incisors was 0.86±0.08, and there was no significant difference between genders (t=-0.88, P>0.05). Only 36.3% (218/600) of the subjects in this study ranged from 0.75 to 0.85. Conclusions: Gender differences should be considered in the esthetic design of anterior teeth; for the width ratios of maxillary anterior teeth, the golden proportion, the RED proportion and golden percentage do not accord with the natural tooth morphological characteristics of Shanxi nationality college students in normal occlusion. Preston proportion and modified golden percentage are of more reference value. The width/height ratio of maxillary central incisors is different from 0.75-0.85.
Cuspid/anatomy & histology* ; Esthetics, Dental ; Female ; Humans ; Male ; Maxilla/anatomy & histology* ; Odontometry ; Students

Dental Pulp Cavity ; anatomy & histology ; Humans ; Male ; Maxilla ; Middle Aged ; Molar ; anatomy & histology ; Odontometry ; Tooth Root ; anatomy & histology

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

INTRODUCTIONAccurate localisation of the greater palatine foramen (GPF) is imperative while negotiating the greater palatine canal for blocking the maxillary nerve within the pterygopalatine fossa. The aim of this study was to define the position of the foramen relative to readily identifiable intraoral reference points in order to help clinicians judge the position of the GPF in a consistently reliable manner.

METHODSThe GPF was studied in 100 dried, adult, unsexed skulls from the state of Maharashtra in western India. Measurements were made using a vernier caliper.

RESULTSThe mean distances of the GPF from the midline maxillary suture, incisive fossa, posterior palatal border and pterygoid hamulus were 14.49 mm, 35.50 mm, 3.40 mm and 11.78 mm, respectively. The foramen was opposite the third maxillary molar in 73.38% of skulls, and the direction in which the foramen opened into the oral cavity was found to be most frequently anteromedial (49.49%). In one skull, the greater and lesser palatine foramina were bilaterally absent. Except for the invariably present incisive canals, there were no accessory palatal foramina, which might have permitted passage of the greater palatine neurovascular bundle in lieu of the absent GPF. To the best of our knowledge, this is the first study of such a non-syndromic presentation.

CONCLUSIONThe GPF is most frequently palatal to the third maxillary molar. For an edentulous patient, the foramen may be located 14-15 mm from the mid-palatal raphe or about 12 mm anterior to the palpable pterygoid hamulus.

Anesthesia ; methods ; Cadaver ; Humans ; India ; Maxilla ; anatomy & histology ; innervation ; Maxillary Nerve ; pathology ; Molar ; anatomy & histology ; Palate, Hard ; abnormalities ; anatomy & histology ; innervation ; Reference Values ; Skull ; anatomy & histology

OBJECTIVE: To provide anatomic data of pterygopalatine fossa(PPF) for endoscopic PPF surgery. METHOD: Fifteen wet adult skull specimen fixed in 10% formaldehyde were studies. From center the skulls were sawed, the middle and inferior turbinate were resected, the anterior and posterior ethmoid sinuses were resected. Then after punch out perpendicular part of palatine bone and posterior wall of maxillary,the pterygopalatine fossa were showed and some related measurements were made. RESULT: This pathway can lead to a good view of pterygopalatine fossa. The main soft structures in PPF were maxillary artery and nerve with their branches. The diameter of artery branches was smaller than 3 mm. CONCLUSION The endoscopic PPF surgery is safe and practical from the anatomic data.
Adult ; Endoscopy ; Ethmoid Sinus ; anatomy & histology ; Humans ; Maxilla ; anatomy & histology ; Maxillary Artery ; anatomy & histology ; Maxillary Sinus ; anatomy & histology ; surgery ; Nasal Cavity ; surgery ; Palate, Hard ; anatomy & histology ; Pterygopalatine Fossa ; anatomy & histology ; surgery

OBJECTIVE: To analyze the esthetic proportions of maxillary anterior teeth in term of the apparent widths proportion of the adjacent teeth and width/height ratio of the clinical crown in 120 Chinese adults. METHODS: Maxillary gypsum casts were obtained from the dental laboratories of stomatological hospitals in North China, Southeast China, and Southwest China, according to the inclusion criteria and exclusion criteria. Standardized digital photographs of each cast were recorded. The apparent widths and actual widths and heights of the central incisors, lateral incisors and canines were determined by ImageJ software for the calculation of apparent widths proportion of the adjacent teeth and width/height ratio of the clinical crown. The ideal apparent widths proportion (Golden proportion and Preston proportion) and width/height ratio (0.80) were tested. The gender, arch side, and regional differences were investigated. RESULTS: The apparent widths proportion of the lateral/central incisor was 0.724±0.047, of the canine/lateral incisor was 0.814±0.092. The width/height ratio of the central incisor was 0.848±0.072, of the lateral incisor was 0.834±0.094, of the canine was 0.883±0.098. The esthetic proportions were different from the predicted ideal ratio (P < 0.001). The apparent widths proportion of lateral/central incisor was significantly larger in the right side than that in the left side (0.730± 0.044 vs. 0.718±0.050), and was significantly smaller in North China than that in Southwest China (0.711±0.051 vs. 0.731±0.044). The width/height ratio of the central incisor was significantly larger in the female than that in the male (0.855±0.074 vs. 0.835±0.068), and in the right side than that in the left side (0.855±0.073 vs. 0.842±0.072). The width/height ratio of the lateral incisor was significantly larger in the female than that in the male (0.843±0.097 vs. 0.817±0.084). CONCLUSION The apparent widths proportion of adjacent teeth and the width/height ratio of the clinical crown in Chinese adults are different from the foreigner's. The esthetic proportion parameters have significant population specificity, and the measurements cannot be generalized as well as it should be applied with caution.
Adult ; Asians ; China ; Cuspid ; Esthetics ; Esthetics, Dental ; Female ; Humans ; Male ; Maxilla/anatomy & histology* ; Odontometry ; Tooth Crown/anatomy & histology*

The purpose of this study was to evaluate whether the cranial and circumaxillary sutures react differently to maxillary expansion (ME) and alternate maxillary expansions and constrictions (Alt-MEC) in a rat model. Twenty-two male Sprague-Dawley rats (6 weeks old) were used and divided into three groups. In ME group (n=9), an expander was activated for 5 days. In Alt-MEC group (9 animals), an alternate expansion and constriction protocol (5-day expansion and 5-day constriction for one cycle) was conducted for 2.5 cycles (25 days total). The control group comprised 4 animals with no appliances used, each of two sacrificed on day 5 and day 25 respectively. Midpalatal suture expansion or constriction levels were assessed qualitatively and quantitatively by bite-wing X-rays and cast models. Distances between two central incisors and two maxillary first molars were measured on cast models after each activation. Circumaxillary sutures (midpalatal, maxillopalatine, premaxillary, zygomaticotemporal and frontonasal suture) in each group were characterized histologically. Results showed that midpalatal suture was widened and restored after each expansion and constriction. At the end of activation, the widths between both central incisors and first molars in Alt-MEC group were significantly larger than those in ME group (P<0.05). Histologically, all five circumaxillary sutures studied were widened in multiple zones in Alt-MEC group. However, only midpalatal suture was expanded with cellular fibrous tissue filling in ME group. Significant osteoclast hyperplasia was observed in all circumaxillary sutures after alternate expansions and constrictions, but osteoclast count increase was only observed in midpalatal suture in ME group. These results suggested that cranial and circumaxillary sutures were actively reconstructed after Alt-MEC, while only midpalatal suture had active reaction after ME.
Animals ; Male ; Mandible ; anatomy & histology ; physiology ; Masticatory Muscles ; anatomy & histology ; physiology ; Maxilla ; anatomy & histology ; physiology ; Range of Motion, Articular ; physiology ; Rats ; Rats, Sprague-Dawley