China ; Cone-Beam Computed Tomography ; Face ; diagnostic imaging ; Humans ; Jaw ; diagnostic imaging ; Mouth ; 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

The odontogenic keratocyst (OKC) is a developmental odontogenic cyst typically occurring in the jaws. Since the first description of OKC was published in 1956, the lesion has been of particular interest because of its specific histopathologic features, high recurrence rate, and aggressive behavior. Recurrences most commonly arise within bone at the site of the original cyst. However, as lining cells may find their way into surrounding tissues either from implantation during surgery or from cortical perforation recurrences may arise at a distance from the original cyst. Here, we report a rare case of recurrent OKC which was first developed in mandible and recurred within the masticatory space.
Diagnostic Imaging ; Jaw ; Mandible ; Masticatory Muscles ; Odontogenic Cysts ; Recurrence

Eosinophilic granuloma, a rare disease, has various clinical manifestations and no specific X-rays features and is thus easily misdiagnosed. This paper reports a case of multifocal eosinophilic granuloma of jaw with long-term follow-up. The patient initially presented with periodontal tissue destruction.The diagnosis, treatment and prognosis of multifocal eosinophilic granuloma of jaw were discussed in combination with the literature to alert this disease in clinical practice.
Diagnosis, Differential ; Eosinophilic Granuloma/diagnostic imaging* ; Humans ; Jaw ; Periodontium ; Radiography

OBJECTIVETo study the edentulous patients facio-maxillary characters, and discuss the base of recording jaw relation by swallowing action.

METHODSForty-three edentulous patients were included in this study, age ranged from 57 to 70 yr, with new comfortable full dentures. Two lateral cephalograms for one patient were taken by SIRONA digital X-ray dental system, one of which was centric occlusion with full denture, another was the end position of swallowing action without denture.

RESULTSThe vertical facial dimensions of male were a little more than that of female. The ratio of lower front facial height/upper front facial height was about 6/5, angle S-N-Po was about 78 approximately 80 degrees. These data may be useful for dentists to make diagnoses if the jaw relation is right or not. Both in vertical or anterior-posterior (horizontal) dimension, the differences between two groups (two actions in one patient) were not significant. It showed that two positions of two actions were the same.

CONCLUSIONSThe SIRONA digital X-ray dental system for cephalometry was swift, and had its own characters. The way of swallowing and occluding is one of efficient methods to record the jaw relation of edentulous patients veraciously and naturally.

Aged ; Cephalometry ; methods ; Deglutition ; Female ; Humans ; Jaw Relation Record ; Jaw, Edentulous ; diagnostic imaging ; Male ; Middle Aged ; Radiography, Dental, Digital

OBJECTIVETo evaluate the mandible angle and to investigate the relationship of angle size to gender, age-group, cortical thickness at the mandibular angle (CTMA), height of mandibular residual body, and edentulous period in the elderly edentulous subjects.

METHODSA total of 356 panoramic radiographs of three groups of subjects were evaluated: the young dentate group, 131 subjects (mean age: 27); the older dentate group, 97 (mean age: 64); and the elderly edentulous group, 128 (ages 76, 81, or 86). Mandibular angle size, CTMA, and height of mandibular residual body were measured from panoramic radiographs. A structured questionnaire was used to determine the history of edentulousness.

RESULTSDifference in angle size was found between dentate men and women (P < 0.05, P < 0.001), but not between the elderly edentulous men and elderly women. The elderly edentulous subjects had larger mandibular angles than did older dentate subjects (P < 0.001). The angle size was negatively related to CTMA only among 76-year-old edentulous women (P < 0.01) and negatively associated with average height of the mandibular residual body in the edentulous men and women (P < 0.01). No association existed between angle size and duration of edentulousness.

CONCLUSIONSElderly edentulous subjects have large mandibular angles and the angle size is correlated with low-height of the mandibular residual body, which suggests that masticatory function of natural dentition and complete denture may influence change of the mandibular angle. The significant relationship of mandibular angle size to CTMA probably indicates the effect of systemic factors on change in the mandibular angle.

Adolescent ; Adult ; Age Factors ; Aged ; Aged, 80 and over ; Alveolar Process ; diagnostic imaging ; pathology ; Cephalometry ; Female ; Humans ; Jaw, Edentulous ; diagnostic imaging ; Male ; Mandible ; diagnostic imaging ; pathology ; Middle Aged ; Radiography

OBJECTIVE: To discuss the coding of full dentition with 32 locations and measure the characteristics of some bony indexes in occlusal-facial digital radiology (DR). METHODS: To select randomly three hundred DR orthopantomogram and code the full dentition, then analyze the diversity of dental patterns. To select randomly one hundred DR lateral cephalogram and measure six indexes (N-S,N-Me,Cd-Gn,Cd-Go,NP-SN,MP-SN) separately by one odontologist and one trained forensic graduate student, then calculate the coefficient variation (CV) of every index and take a correlation analysis for the consistency between two measurements. RESULTS: (1) The total diversity of 300 dental patterns was 75%.It was a very high value. (2)All six quantitative variables had comparatively high CV value.(3) After the linear correlation analysis between two measurements, all six coefficient correlations were close to 1. This indicated that the measurements were stable and consistent. CONCLUSION The method of coding full dentition in DR orthopantomogram and measuring six bony indexes in DR lateral cephalogram can be used to forensic identification.
Cephalometry/methods* ; Facial Bones/diagnostic imaging* ; Female ; Forensic Dentistry ; Humans ; Image Processing, Computer-Assisted/methods* ; Jaw/diagnostic imaging* ; Male ; Radiography, Dental, Digital/methods* ; Radiography, Panoramic ; Tooth/diagnostic imaging*

Adult ; Humans ; Imaging, Three-Dimensional ; Jaw Fixation Techniques ; Joint Dislocations ; diagnostic imaging ; etiology ; surgery ; Male ; Mandible ; surgery ; Mandibular Condyle ; diagnostic imaging ; injuries ; surgery ; Mandibular Fractures ; complications ; diagnostic imaging ; surgery ; Tomography, X-Ray Computed

BACKGROUND: Temporomandibular joint disorder (TMD) is a group of musculoskeletal conditions characterized by pain in the pre-auricular area, limitation of jaw movement and palpable muscle tenderness. Thermography is a nonionizing, noninvasive diagnostic alternative for the evaluation of TMD. This study was conducted to evaluate the usefulness of thermography in the assessment of TMD. METHODS: Thermography was conducted on the 61 patients who had been diagnosed with TMD, and on the 34 normal symptom-free volunteers. The temperature differences between opposite sides of the temporomandibular joint (DeltaTTMJ) and the masseter muscle (DeltaTMST) were calculated. The sensitivity and specificity of thermography was calculated at the cut off values of 0.2, 0.3, and 0.4 degrees C. RESULTS: In the patient group, the DeltaTTMJ was 0.42 +/- 0.38 degrees C and the DeltaTMST was 0.38 +/- 0.33 degrees C, whereas in the control group the DeltaTTMJ was 0.10 +/- 0.07 degrees C and the DeltaTMST 0.15 +/- 0.10 degrees C. In addition, the patient group demonstrated a significantly lower level of thermal symmetry than the control group (P < 0.001) in both the temporomandibular joints and the masseter muscles. The sensitivity of thermography at the cut off values of 0.2, 0.3 and 0.4 degrees C was 67.2, 49.2, and 42.6% in the temporomandibular joint (TMJ) and 60.7, 49.2 and 37.7% in the masseter muscle, respectively. The specificity of thermography at the cut off values of 0.2, 0.3 and 0.4 degrees C was 88.2, 100, and 100% in the TMJ and 61.8, 91.2 and 100% in the masseter muscles, respectively. The accuracy of thermography at the cut off values of 0.2, 0.3 and 0.4 degrees C was 74.7, 67.4, and 63.2% in TMJ and 61.1, 64.2 and 60.0% in the masseter muscles, respectively. CONCLUSIONS: Temperature differences exist between the opposite sides of the TMD and masseter muscles in patients with TMD. Although the sensitivity of thermography in the diagnosis of TMD is low, it has high specificity in the evaluation of TMD, and is therefore applicable to patients with TMD.
Diagnosis ; Diagnostic Imaging ; Humans ; Jaw ; Masseter Muscle ; Myalgia ; Sensitivity and Specificity ; Temporomandibular Joint Disorders ; Temporomandibular Joint* ; Thermography* ; Volunteers

OBJECTIVETo establish the automatic X-ray cephalometric analysis system to simplify cephalometric steps and to provide a convenient and reliable method for cephalometric analysis.

METHODSThe system which was programmed by visual-c language, and graphics and image processing techniques and artificial intelligence were used. The techniques related to computer digital image processing and pattern recognition such as Median filtering, Histogram equalization, Laplacian and Canny edge detection were introduced. It could automatically outline the contour lines of the hard and soft tissues by establishing the templates of the variable anatomical structures.

RESULTSThe following functions were established: (1) automatically outlining the contour lines of the soft tissues. (2) automatically recognizing, measuring and analysing the landmarks of soft tissues. (3) automatically recognizing porion, sella and the landmarks of the mandible. (4) automatically building the contour lines of the hard tissues. In brief, the system used the more advanced methods, calculated more precisely and saved more time and energy than other systems.

CONCLUSIONThe system is a more convenient and precise tool in cephalometry.

Cephalometry ; methods ; Humans ; Image Processing, Computer-Assisted ; Jaw ; anatomy & histology ; diagnostic imaging ; Orthodontics ; methods ; Radiography ; Sensitivity and Specificity