Rapid palatal expansion is commonly uesd to correct maxillary transverse deficiency. The timing and effects of palatal expansion, and the choice of palatal expansion devices are related to the condition of midpalatal suture. Nowadays, there are several methods to assess the condition of midpalatal suture, including physiological age, skeletal age, occlusal film, CT, ultrasonography and so on. This narrative review seeks to review these methods for assessment of midpalatal suture.
Palatal Expansion Technique ; Cranial Sutures/diagnostic imaging* ; Maxilla/diagnostic imaging* ; Palate/diagnostic imaging*

OBJECTIVE: To compare the registration accuracy of three-dimensional (3D) facial scans for the design of full-arch implant supported restoration by five methods and to explore the suitable registration method. METHODS: According to the criteria, ten patients with maxillary edentulous jaw or end-stage dentition requiring implant supported restorations were enrolled in this study. A special rim with individual feature marks reflected appropriate occlusal relationship and esthetic characteristics was made for each patient. Both 3D facial scan data of natural laughter and with opener traction to expose the teeth or occlusal rim of each patient were acquired by facial scan and input to the digital analysis software Geomagic Qualify 2012. The dataset was superimposed by five different methods: seven facial anatomical landmark points alignment, facial immobile area alignment (forehead and nasal area), facial anatomical landmark points and immobile area combining alignment, facial feature points alignment, facial and intraoral feature points alignment with the same local coordinate system. The three-dimensional deviation of the same selected area was calculated, the smaller the deviation, the higher the registration accuracy. The 3D deviation was compared among the three registration methods of facial anatomical landmark points, facial immobile area alignment and the combination of the above two methods. Friedman test was performed to analyze the difference among the three methods (α=0.05). The effect of the aid of the facial and intraoral feature points were evaluated. Paired t test were performed to analyze the difference (P<0.05). RESULTS: The average three-dimensional deviation of the selected area after alignment with the facial anatomical landmarks was (1.501 2±0.406 1) mm, significantly larger than that of the facial immobile area best-fit alignment [(0.629 1±0.150 6) mm] and the combination of the two methods[(0.629 1±0.150 6) mm] (P < 0.001). The aid of the facial feature points could significantly reduce the deviation (t=1.001 3, P < 0.001). There was no significant statistical difference in the remaining groups. CONCLUSION The forehead area of the 3D facial scan can be exposed as much as possible. The establishment of facial characteristic landmark points and the use of the invariant area alignment can improve the accuracy of registration. It should be clinically feasible to apply three-dimensional facial scan to the design of full-arch implant supported restoration with the registration of the immobile area on the face especially the forehead area.
Computer-Aided Design ; Humans ; Imaging, Three-Dimensional ; Jaw, Edentulous/diagnostic imaging* ; Maxilla/diagnostic imaging* ; Radionuclide Imaging

OBJECTIVE: To explore more concise and unified forensic identification indexes for people with none dental disease in digital orthopantomogram. METHODS: To select randomly 170 digital orthopantomogram with none dental disease. Then to select indexes for full dentition patterns and dental alignment patterns according to the dental physiological variations and the characters of dental alignment respectively. Finally diversity of the indexes would be evaluated by statistical analysis. RESULTS: The group with none dental disease had 74 kinds of full dentition pattern in 170 samples, thus its diversity was 43.53%. The group had 129 kinds of dental alignment pattern, thus its diversity was 75.88%. The group had 150 kinds of full dentition/dental alignment pattern, thus its diversity was 88.24%. CONCLUSION The diversity of the full dentition pattern was not very good. So the full dentition coding was not very effective when it was used solely. The diversity of dental alignment pattern was good. So the method of dental alignment coding could be used in the maxillofacial forensic identification. If the group was coded by the full dentition and dental alignment pattern at the same time, its diversity was better than any single pattern. So the method would be valuable in forensic identification.
Dentition ; Forensic Dentistry ; Humans ; Mandible/diagnostic imaging* ; Maxilla/diagnostic imaging* ; Radiography, Dental, Digital ; Radiography, Panoramic/methods*

OBJECTIVETo measure the thickness of facial bone wall of maxillary anterior teeth and premolars based on cone beam computed tomography (CBCT) images.

METHODSCBCT images from 118 patients were collected from the Affiliated Stomatology Hospital of Zhejiang University. The thickness perpendicular to the long axis of facial bone wall was measured at two locations: 4 mm apical to the cementoenamel junction (point 1) and the middle of the root (point 2).

RESULTSThe thickness of the facial bone walls of central incisors, lateral incisors and canines ranged from 0.5 to 1.5 mm. A thin facial bone wall (<1.0 mm) was quite frequent in central incisors (44.1% at point 1, 56.8% at point 2), lateral incisors (65.2% at point 1, 89.8% at point 2) and canines (45.8% at point 1, 61.0% at point 2). In contrast, the majority of examined first premolars (77.1% at point 1, 68.7% at point 2) and second premolars (94.1% at point 1, 94.1% at point 2) exhibited a thick facial bone wall (>1.0 mm).

CONCLUSIONA thin facial bone wall of teeth in the anterior maxilla is common. Radiographic analysis of facial bone wall using CBCT is recommended for selection of appropriate treatment approach.

Adult ; Bicuspid ; diagnostic imaging ; Cone-Beam Computed Tomography ; Female ; Humans ; Incisor ; diagnostic imaging ; Male ; Maxilla ; diagnostic imaging ; Young Adult

OBJECTIVES: To compare the root length of maxillary and mandibular anterior teeth between open bite patients and normal overbite patients via cone-beam computed tomography (CBCT) as well as the root length of anterior teeth in different degree of open bite patients, and to analyze the correlation between the degree of open bite and root length. METHODS: A total of 106 untreated patients were enrolled retrospectively (53 anterior open bite patients and 53 normal overbite patients).Three-dimensional position of the CBCT image for the patient's teeth was performed using Dolphin software. The median sagittal plane of the tooth was used as the measurement plane, and the line connecting the apical point and the midpoint between the labial and lingual cementoenamel junctions was defined as the root length. Independent RESULTS: Significant differences were found in the root length of maxillary and mandibular anterior teeth between the open bite group and the normal overbite group ( CONCLUSIONS The root length of maxillary and mandibular anterior teeth in the open bite patients is shorter than that in the normal overbite patients, and the severer the degree of open bite, the shorter the root length of the mandibular central incisor tends to be. There is a certain relationship between maxillary anterior teeth and the root length of anterior teeth.
Cone-Beam Computed Tomography ; Humans ; Incisor/diagnostic imaging* ; Maxilla/diagnostic imaging* ; Open Bite/diagnostic imaging* ; Retrospective Studies

OBJECTIVE: To measure the three-dimensional morphology of the labial supraosseous gingiva (SOG) and the thickness of related labial bone in maxillary anterior teeth of periodontally healthy Han nationality youth using soft tissue indirect imaging cone-beam computed tomography (CBCT). METHODS: Twenty-five periodontally healthy subjects (11 males and 14 females) with 150 maxillary anterior teeth were involved in this study. A special impression with radiopaque material including the maxillary teeth was made, then a CBCT scan with the elastomeric matrix in position was taken for each subject. The imaging data were generated and transferred to a volumetric imaging software in which three-dimensional reconstruction was conducted and the image analyses were carried out. Measurements were made at the site of labial center of the maxillary anterior teeth. The height of the SOG, the distance between cemento-enamel junction (CEJ) and bone crest, the gingival thickness at the CEJ, and the thickness of bone 2 mm below the labial bone crest were measured and the correlation analysis between the parameters was made. All the data analyses were performed using SPSS 22.0. The data were analyzed with ANVOA and Pearson correlation tests with the significance level at α=0.05. RESULTS: The mean SOG values were (3.49±0.70) mm, (3.48±0.81) mm, and (3.54±0.67) mm for central incisors, lateral incisors and canines, respectively. There were no statistically significant differences among the different sites (P > 0.05). The mean gingival thickness values were (1.45±0.23) mm, (1.13±0.24) mm, (1.14±0.22) mm for central incisors, lateral incisors and canines, respectively. The gingival thickness of the central incisors was the largest among the maxillary anterior teeth with statistically significant difference (P < 0.05). No correlation was found between the SOG and gingival thickness among the maxillary anterior teeth (P > 0.05). CONCLUSION The gingival thickness of central incisors was the largest and the supraosseous gingival height had no correlation with gingival thickness among the periodontally healthy maxillary anterior teeth.
Adolescent ; Cone-Beam Computed Tomography ; Female ; Gingiva/diagnostic imaging* ; Humans ; Incisor/diagnostic imaging* ; Male ; Maxilla/diagnostic imaging* ; Tooth Cervix

OBJECTIVESTo evaluate the naso-maxillary complex width and pharyngeal airway volume changes after rapid maxillary expansion (RME).

METHODSThirty-five patients were selected (18 males, 17 females, mean age, 12.1 ± 1.1 years). All patients underwent orthodontic treatment with Hyrax palatal expanders. Cone-beam CT (CBCT) scan was taken before treatment (T0), 16 days (T1) and three months (T3) after RME. Naso-maxillary complex width and pharyngeal airway volume were measured.

RESULTSAfter treatment the width of piriform aperture and maxillary width were significantly increased compared with that before treatment (P < 0.05). Three months after RME, no statistical difference was found in maxillary width compared with that before treatment. The nasopharyngeal volume significantly increased by 29.9% compared with that before treatment (P < 0.05), and the volume remained relatively stable after three months.

CONCLUSIONSRME resulted in a significant increase in the naso-maxillary complex width and nasopharyngeal volume.

Cone-Beam Computed Tomography ; Female ; Humans ; Imaging, Three-Dimensional ; Male ; Maxilla ; diagnostic imaging ; Nose ; diagnostic imaging ; Palatal Expansion Technique ; Palate ; diagnostic imaging ; Pharynx ; diagnostic imaging

OBJECTIVETo evaluate the degree and pattern of alveolar bone defect in aggressive periodontitis (AgP) using cone-beam CT (CBCT), and to investigate the distribution of alveolar bone defects in aggressive periodontitis.

METHODSForty AgP patients (age: 14-36 years, male: 15 cases, female: 25 cases) were selected by simple random method and scanned by CBCT. NNT software was applied to measure the average degree of alveolar bone defects and bone loss types in different regions.

RESULTSIn forty AgP patients, 86.6% (3,769/4,352) sites presented moderate and severe alveolar bone defects. In the maxilla, the molar areas presented the heaviest alveolar bone defect [(6.3±0.7) mm], the canine areas showed the lightest bone loss [(4.8±0.8) mm]. In the mandible, the incisal areas presented the heaviest alveolar bone defect [(5.9±0.9) mm], the canine areas showed the lightest bone loss[(5.1±0.7) mm]. The degree of alveolar bone defect in the areas of maxillary canine, maxillary molars, mandibular premolar was significantly different (P<0.05). The degree of alveolar bone defect in mandibular canine and mandibular molars was significantly differenct (P<0.01). The most serious alveolar bone defect was in the mesial side of maxillary molar [(6.9±0.7) mm] and the mesial side of mandibular incisor [(6.5±1.1) mm]. The oblique bone defects were found in the mesial part of the first molars in mandibula [13.6% (42/308)], the first molars in maxilla [12.0% (39/316)] and the first premolar in maxilla [10.8% (34/316)].

CONCLUSIONSThe alveolar bone defects of generalized AgP patients were serious. The most serious areas were located in the mesial side of maxillary molars and the mesial side of mandibular incisor.

Adolescent ; Adult ; Aggressive Periodontitis ; diagnostic imaging ; Alveolar Process ; diagnostic imaging ; Bicuspid ; Cone-Beam Computed Tomography ; Cuspid ; Female ; Humans ; Incisor ; Male ; Mandible ; diagnostic imaging ; Maxilla ; diagnostic imaging ; Molar ; Software

Objective: To measure the labial gingival thickness and bone lamella thickness in the maxillary anterior area using digital method, and to analyze the correlation between the two, so as to provide a reference for esthetic restoration and implantation treatment of the upper anterior area. Methods: Fifty-seven patients [23 males, 34 females, (25.8±4.5) years old] who planned to receive posterior dental implant restoration were recruited randomly with the inclusion and exclusion criteria in Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University from May 2020 to October 2020. The 3Shape software was used to perform oral scanning, and cone beam CT (CBCT) was taken for each patient. The image data was fitted and registered by the 3Shape software. The gingival thickness at 2 mm below the gingival margin, bone thickness and gingival thickness at 2 and, 4 mm below the crest of the labial alveolar crest in maxillary central incisors, lateral incisors and canines, were measured. Results: The gingival thickness at 2 mm below the gingival margin of maxillary central incisors, lateral incisors and canines was (1.42±0.21), (1.19±0.17) and (1.23±0.20) mm respectively (F=12.47, P<0.001). The gingival thickness at 2 mm below gingival margin and 4 mm below crest of residual ridge in the male patients were (1.31±0.21) and (0.67±0.22) mm, and those in the female patients were (1.26±0.22) and (0.58±0.19) mm respectively, and there were statistically significant differences in the gingival thickness between the "2 mm below gingival margin" group and the "4 mm below crest of residual ridge" group (t=2.01 and 3.97, P<0.05). There was a positive correlation between gingival thickness and alveolar bone thickness at 2 mm and 4 mm below the crest of residual ridge in maxillary anterior region, and the correlation coefficients (r) were 0.387 and 0.344 respectively (P<0.05). Conclusions: Gingival thickness of maxillary anterior area is related to the tooth position and gender. The gingival thickness of men is greater than that of women.The gingival thickness at 2 and 4 mm below the crest of the alveolar crest is positively correlated with the thickness of the alveolar bone.
Adult ; Alveolar Process/diagnostic imaging* ; Cone-Beam Computed Tomography ; Esthetics, Dental ; Female ; Gingiva/diagnostic imaging* ; Humans ; Incisor/diagnostic imaging* ; Male ; Maxilla/diagnostic imaging* ; Young Adult

The purpose of this study was to develop a new way to localize the impacted canines from three dimensions and to investigate the root resorption of the adjacent teeth by using cone beam computed tomography (CBCT). Forty-six patients undergoing orthodontic treatments and having impacted canines in Tongji Hospital were examined. The images of CBCT scans were obtained from KaVo 3D exam vision. Angular and linear measurements of the cusp tip and root apex according to the three planes (mid-sagittal, occlusal and frontal) have been taken using the cephalometric tool of the InVivo Dental Anatomage Version 5.1.10. The measurements of the angular and linear coordinates of the maxillary and mandibular canines were obtained. Using this technique the operators could envision the location of the impacted canine according to the three clinical planes. Adjacent teeth root resorption of 28.26 % was in the upper lateral incisors while 17.39% in upper central incisors, but no lower root resorption was found in our samples. Accurate and reliable localization of the impacted canines could be obtained from the novel analysis system, which offers a better surgical and orthodontic treatment for the patients with impacted canines.
Adolescent ; Adult ; Cephalometry ; methods ; Child ; Cone-Beam Computed Tomography ; methods ; Cuspid ; diagnostic imaging ; Female ; Humans ; Imaging, Three-Dimensional ; methods ; Incisor ; diagnostic imaging ; Male ; Maxilla ; diagnostic imaging ; Reproducibility of Results ; Root Resorption ; diagnostic imaging ; Tooth, Impacted ; diagnostic imaging ; Young Adult