OBJECTIVE: To evaluate the type of wound healing following modified crown lengthening surgery in dog model to provide a biological basis for its clinical application. METHODS: Flap surgery, traditional crown lengthening procedure and modified crown lengthening procedure were performed on the right maxillary central incisor, the left maxillary central incisor and the left maxillary first lateral incisor respectively of five male beagle dogs. The right maxillary first lateral incisors with no surgical intervention were used as controls. Thirty-six weeks after the experimental procedure, tissue blocks were harvested and prepared for histological examination and analysis. RESULTS: Histometric examination of buccolingual sections stained with hematoxylin-eosin demonstrated that the type of wound healing in the flap surgery group was re-attachment, similar to the control group. For the traditional crown lengthening surgery group, all of the five beagle dogs had lamellar cementum defects on root surface, the wound healing of four beagle dogs was new attachment accompanied by new cementum formation at cementum defect areas and the suprac-restal connective tissue was functionally oriented perpendicular to the new cementum. The wound healing of the other beagle dog was long junctional epithelial attachment, in which the junctional epithelium extended to the apical terminus of the cementum defect. In the modified crown lengthening surgery group, four beagle dogs had cementum defects on root surface (two lamellar cementum defects and two shallow platform-like cementum defects), the wound healing of three beagle dogs was new attachment, however, the supracrestal connective tissue was parallel to the root surface. The type of wound healing of another one beagle dog was long junctional epithelial attachment. Wound healing of one beagle dog in this group could not be characterized due to incomplete dissection. CONCLUSION Wound healing in the modified crown lengthening surgery group was similar to the traditional crown lengthening surgery group, and two types of wound healing were observed: new attachment and long junctional epithelium attachment. Neither type of root treatment procedure (root planing or root reshaping) nor root surface defect pattern (the lamellar cementum defect or shallow platform-like cementum defect) influenced the observed type of wound healing.
Animals ; Connective Tissue ; Crown Lengthening ; Dogs ; Eosine Yellowish-(YS) ; Epithelial Attachment/pathology* ; Hematoxylin ; Male ; Tooth Root/surgery* ; Wound Healing

Charcot-Marie-Tooth disease (CMT) is the commonest form of inherited neuropathy and has an incidence of 1/2500. CMT1A is the commonest subtype of CMT, which is caused by duplication of peripheral myelin protein 22 (PMP22) gene and accounts for approximately 50% of CMT diagnosed by genetic testing. Duplication of PMP22 may influence the production of PMP22 mRNA and protein, and interfere with the proliferation, differentiation and apoptosis of Schwann cells. In addition, deregulation of NRG1/ErbB pathway and lipid metabolism can also lead to dysfunction of Schwann cells. Such factors may disturb the myelination process, leading to axon degeneration, muscle weakness, and atrophy subsequently. Accordingly, drug therapies for CMT1A are developed by targeting such factors. PXT3003, antisense oligonucleotides (ASOs) and small interfering RNA (siRNA) are supposed to down-regulate the level of PMP22 mRNA, while recombinant human NRG-1 (rhNRG1) and neurotrophin-3 (NT-3) may enhance Schwann cells survival and differentiation. In addition, lipid-supplemented diet may remedy the defect of lipid metabolism and maintain the proper structure of myelin. Other targeting drugs include ascorbic acid, progesterone antagonists, IFB-088, ADX71441, and ACE-083. This review is to sum up the pathogenesis of CMT1A and promising targeting drug therapies for further research.
Cell Differentiation ; Charcot-Marie-Tooth Disease ; genetics ; pathology ; therapy ; Genetic Testing ; Humans ; Schwann Cells ; cytology

PURPOSE: The prevalence of supernumerary teeth has been reported to be between 0.1% and 3.8%. The aim of this study was to determine the prevalence, clinical significance, and associated pathologies of fourth molars based on a retrospective study and a literature review. MATERIALS AND METHODS: A 5-year retrospective prevalence study was conducted at the Department of Oral Diagnosis and Dentomaxillofacial Radiology of Okayama University Hospital, Okayama, Japan. The study involved extracting data from the digital records of patients from January 1, 2013 through December 31, 2017. The sampling frame included all patients who had panoramic radiographs, cone-beam computed tomography (CT), and multislice CT images during the period under review. RESULTS: A total of 26,721 cases were reviewed and 87 fourth molars were identified. The prevalence of fourth molars in the 5-year study at Okayama was calculated as 0.32%. The mean age of patients with a fourth molar was 30.43 years, and the male-to-female ratio was 1:0.98. The vast majority of cases were in the maxilla (92%) and had normal shapes (89.7%); furthermore, 82.8% of cases were unerupted. CONCLUSION: The prevalence of fourth molars in the study population was found to be 0.32%, and fourth molars occurred with approximately equal frequency in males and females. Fourth molars were more common in the maxilla and were predominantly unerupted and small.
Cone-Beam Computed Tomography ; Cross-Sectional Studies ; Diagnosis, Oral ; Female ; Humans ; Japan ; Male ; Maxilla ; Odontogenic Cysts ; Odontoma ; Pathology ; Prevalence ; Retrospective Studies ; Tooth, Supernumerary

PURPOSE: The aims of this study were first, to compare panoramic radiography with cone-beam computed tomography (CBCT) for evaluating topographic relationships, such as the classification of maxillary posterior teeth and their distance to the maxillary sinus floor; and second, to determine the relationship between maxillary sinus pathology and the presence of apical lesions. MATERIALS AND METHODS: In total, 285 paired CBCT and panoramic radiography records of patients (570 maxillary sinuses) were retrospectively analyzed. Both imaging modalities were used to determine the topographic relationship of the maxillary posterior teeth to the sinus floor. Mucosal thickening >2 mm was considered a pathological state. Data were analyzed using the chi-square, Wilcoxon, and Mann-Whitney U tests. Odds ratios (ORs) and confidence intervals (CIs) were calculated. RESULTS: The closest vertical distance measurements made between posterior maxillary teeth roots and the maxillary sinus on panoramic radiography and CBCT scans showed statistically significant differences from each other (P<0.05). Compared to panoramic radiography, CBCT showed higher mean values for the distance between the maxillary sinus floor and maxillary posterior teeth roots. The CBCT images showed that at least 1 apical lesion adjacent to the right maxillary sinus increased the risk of maxillary sinus pathology by 2.37 times (OR, 2.37; 95% CI, 1.58-3.55, P<0.05). CONCLUSION: Panoramic radiography might lead to unreliable diagnoses when evaluating the distance between the sinus floor and posterior roots of the maxillary teeth. Periapical lesions anatomically associated with maxillary sinuses were a risk factor for sinus mucosal thickening.
Classification ; Cone-Beam Computed Tomography ; Diagnosis ; Humans ; Maxillary Sinus ; Odds Ratio ; Paranasal Sinus Diseases ; Pathology ; Radiography, Panoramic ; Retrospective Studies ; Risk Factors ; Tooth

OBJECTIVES: Foreign bodies (FBs) account for 3.8% of all pathologies of the head and neck region, and approximately one third of them are missed on initial examination. Thus, FBs represent diagnostic challenges to maxillofacial surgeons, rendering it necessary to employ an appropriate imaging modality in suspected cases. MATERIALS AND METHODS: In this cross-sectional study, five different materials, including wood, metal, glass, tooth and stone, were prepared in three sizes (0.5, 1, and 2 mm) and placed in three locations (soft tissue, air-filled space and bone surface) within a sheep's head (one day after death) and scanned by panoramic radiography, cone-beam computed tomography (CBCT), and ultrasonography (US) devices. The images were reviewed, and accuracy of the detection modalities was recorded. The data were analyzed statistically using the Kruskal-Wallis, Mann-Whitney U-test, Friedman, Wilcoxon signed-rank and kappa tests (P < 0.05). RESULTS: CBCT was more accurate in detection of FBs than panoramic radiography and US (P < 0.001). Metal was the most visible FB in all of modalities. US was the most accurate technique for detecting wooden materials, and CBCT was the best modality for detecting all other materials, regardless of size or location (P < 0.05). The detection accuracy of US was greater in soft tissue, while both CBCT and panoramic radiography had minimal accuracy in detection of FBs in soft tissue. CONCLUSION: CBCT was the most accurate detection modality for all the sizes, locations and compositions of FBs, except for the wooden materials. Therefore, we recommend CBCT as the gold standard of imaging for detecting FBs in the maxillofacial region.
Cone-Beam Computed Tomography ; Cross-Sectional Studies ; Foreign Bodies ; Glass ; Head ; In Vitro Techniques ; Neck ; Oral and Maxillofacial Surgeons ; Pathology ; Radiography, Panoramic ; Tooth ; Ultrasonography ; Wood

OBJECTIVE: To observe the change of soft and hard tissue in dental immediate implantation and immediate reconstruction in anterior region after loading 3 years. METHODS: Patients with single anterior tooth loss in the Department of Second Dental Center, Peking University School and Hospital of Stomatology from October 2008 to October 2012 were enrolled. The gingival papilla height, labial gingival margin level and peri-implant bone level were measured immediately after the permanent restoration and 3 years later. RESULTS: In the study, 20 patients were treated by immediate implantation and immediate reconstruction for 22 implants; 24 patients were treated by delayed implant for 29 implants. Implant stability quotient (ISQ) value of the two groups showed no significant difference before permanent restoration (P>0.05). In all the cases after loading 3 years, the average mesial gingival papilla height in implant area of the immediate group and delayed group changed by (0.34±0.54) mm and (0.05±0.39) mm respectively (P=0.07), the distal gingival papilla height changed by (0.43±0.42) mm and (0.36±0.48) mm respectively (P=0.13), while the labial gingival margin level shrinkages were (0.70±0.40) mm and (0.62±0.34) mm respectively (P=0.23). Peri-implant bone losses in the mesial side were (1.02±0.50) mm and (0.88±0.46) mm respectively (P=0.53), while those in the distal side were (1.05±0.34) mm and (0.95±0.47) mm respectively (P=0.21). All these indicators showed no significant difference between the two groups (P>0.05); When the permanent prostheses delivered, the distributions of the gingival papilla index were different between the two groups whether in the mesial side or in the distal side (P<0.05). CONCLUSION The changes of the soft and hard tissue of the immediate implantation and immediate reconstruction in anterior region after loading 3 years were basically equivalent to the conventional implant restoration. But, the former was obviously better than the latter in reducing the duration of treatment and in getting the ideal dental papilla aesthetic effect.
Dental Implantation, Endosseous ; Dental Implants, Single-Tooth ; Dental Prosthesis, Implant-Supported ; Dental Restoration, Temporary ; Esthetics, Dental ; Gingiva/pathology* ; Humans ; Immediate Dental Implant Loading ; Maxilla/pathology* ; Prospective Studies ; Treatment Outcome

PURPOSE: The aim of the present exploratory study was to evaluate extraction socket healing at sites with a history of periodontal and endodontic pathology. METHODS: The mandibular 4th premolar teeth in 5 adult beagle dogs served as experimental units. Periodontal and endodontic lesions were induced in 1 premolar site in each animal using wire ligatures and pulpal exposure over 3 months (diseased sites). The contralateral premolar sites served as healthy controls. The mandibular 4th premolar teeth were then extracted with minimal trauma, followed by careful wound debridement. The animals were sacrificed at days 1, 7, 30, 60, and 90 post-extraction for analysis, and the healing patterns at the healthy and diseased extraction sites were compared using radiography, scanning electron microscopy, histology, and histometry. RESULTS: During the first 7 days of healing, a significant presence of inflammatory granulation tissue was noted at the diseased sites (day 1), along with a slightly accelerated rate of fibrin clot resolution on day 7. On day 30, the diseased extraction sites showed a greater percentage of persistent fibrous connective tissue, and an absence of bone marrow formation. In contrast, healthy sites showed initial signs of bone marrow formation on day 30, and subsequently a significantly greater proportion of mature bone marrow formation on both days 60 and 90. Radiographs exhibited sclerotic changes adjoining apical endodontic lesions, with scanning electron microscopy showing collapsed Volkmann canals protruding from these regions in the diseased sites. Furthermore, periodontal ligament fibers exhibited a parallel orientation to the alveolar walls of the diseased sites, in contrast to a perpendicular arrangement in the healthy sites. CONCLUSIONS: Within the limitations of this study, it appears that a history of periodontal and endodontic pathology may critically affect bone formation and maturation, leading to delayed and compromised extraction socket healing.
Adult ; Animals ; Bicuspid ; Bone Marrow ; Connective Tissue ; Debridement ; Dogs ; Fibrin ; Granulation Tissue ; Humans ; Ligation ; Microscopy, Electron, Scanning ; Models, Biological ; Osteogenesis ; Pathology* ; Periodontal Ligament ; Radiography ; Tooth ; Wound Healing ; Wounds and Injuries

BACKGROUNDX-linked Charcot-Marie-Tooth type 1 (CMT1X) disease is one of the most common forms of inherited neuropathy caused by mutations in the gap junction beta-1 protein (GJB1) gene (also known as connexin 32). This study presented the clinical and genetic features of a series of Chinese patients with GJB1 gene mutations.

METHODSA total of 22 patients from unrelated families, who were referred to Department of Neurology, Peking University First Hospital from January 2005 to January 2016, were identified with GJB1 mutations. Their clinical records and laboratory findings were retrospectively collected and reviewed. Mutations in the GJB1 gene were analyzed by targeted next-generation sequencing (NGS). Nucleotide alternations were confirmed with Sanger sequencing.

RESULTSThe CMT1X patients predominantly showed distal muscle weakness of lower limbs with mild sensory disturbance. The mean age of onset was 15.6 ± 8.7 years (ranging from 1 year to 42 years). The sudden onset of cerebral symptoms appeared in four patients (18.2%); two were initial symptoms. One case had constant central nervous system (CNS) signs. There were 19 different heterozygous mutations, including 15 known mutations and four novel mutations (c.115G>T, c.380T>A, c.263C>A, and c.818_819insGGGCT). Among the 22 Chinese patients with CMT1X, the frequency of the GJB1 mutation was 4.5% in transmembrane domain 1 (TM1), 4.5% in TM2, 22.7% in TM3, 9.1% in TM4, 4.5% in extracellular 1 (EC1), 27.3% in EC2, 9.1% in intracellular loop, 13.6% in the N-terminal domain, and 4.5% in the C-terminal domain. CMT1X with CNS impairment appeared in five (22.7%) of these patients.

CONCLUSIONSThis study indicated that CNS impairment was not rare in Chinese CMT1X patients. Mutations in the EC2 domain of the GJB1 gene were hotspot in Chinese CMT1X patients.

Adolescent ; Adult ; Central Nervous System ; metabolism ; Charcot-Marie-Tooth Disease ; genetics ; pathology ; Child ; Child, Preschool ; Connexins ; genetics ; DNA Mutational Analysis ; Electrophysiology ; Female ; Genotype ; Humans ; Infant ; Male ; Mutation ; Phenotype ; Retrospective Studies ; Young Adult

Dental pathology has the potential to provide insight into the interpretation of the health and life style of past population. In particular, dental pathologies are strongly correlated to subsistence pattern, diet habits and food-preparation techniques. For this reason, my studies have focused on analyses of dental diseases (e.g., caries, abscesses, ante-mortem tooth loss, enamel hypoplasia, dental attrition, and periodontal diseases). The purpose of this study is to investigate the prevalence of dental pathologies of the Imdang population dating to between A.D. 3rd and A.D. 7th centuries (Three Kingdoms Period). In this study, through a macroscopic observation of dental remains from 138 individuals of the Imdang site, the prevalence of caries, abscess and ante-mortem tooth loss was examined. The association between sex, age and the frequencies of pathology was analyzed by the Chi-square tests. The results showed that the frequency of dental pathologies was consistently low level in Imdang population. Caries prevalence in the Imdang population was higher in females (6.15%) that in males (4.89). Among dental pathologies, abscess prevalence (0.7%) was lowest in Imdang population. Meanwhile, AMTL prevalence was 10.81% in males and 3.8% in females. There is a statistically significant difference between the anterior teeth of males and females (p<0.05). This study revealed that the rate of dental caries, abscess and AMTL in the Three Kingdoms Period population was relatively low level. This study is the first report of the patterns of dental pathologies in the Three Kingdoms Period population. It is necessary to investigate more number of pathologic markers that needed for deeper understanding of the multi-faceted nature of dental pathologies of ancient populations.
Abscess ; Dental Caries ; Dental Enamel Hypoplasia ; Female ; Food Habits ; Gyeongsangbuk-do* ; Humans ; Korea* ; Life Style ; Male ; Pathology* ; Prevalence ; Stomatognathic Diseases ; Tooth ; Tooth Loss

BACKGROUNDThe accuracy of three-dimensional (3D) reconstructions from cone-beam computed tomography (CBCT) has been particularly important in dentistry, which will affect the effectiveness of diagnosis, treatment plan, and outcome in clinical practice. The aims of this study were to assess the linear, volumetric, and geometric accuracy of 3D reconstructions from CBCT and to investigate the influence of voxel size and CBCT system on the reconstructions results.

METHODSFifty teeth from 18 orthodontic patients were assigned to three groups as NewTom VG 0.15 mm group (NewTom VG; voxel size: 0.15 mm; n = 17), NewTom VG 0.30 mm group (NewTom VG; voxel size: 0.30 mm; n = 16), and VATECH DCTPRO 0.30 mm group (VATECH DCTPRO; voxel size: 0.30 mm; n = 17). The 3D reconstruction models of the teeth were segmented from CBCT data manually using Mimics 18.0 (Materialise Dental, Leuven, Belgium), and the extracted teeth were scanned by 3Shape optical scanner (3Shape A/S, Denmark). Linear and volumetric deviations were separately assessed by comparing the length and volume of the 3D reconstruction model with physical measurement by paired t- test. Geometric deviations were assessed by the root mean square value of the imposed 3D reconstruction and optical models by one-sample t-test. To assess the influence of voxel size and CBCT system on 3D reconstruction, analysis of variance (ANOVA) was used (μ = 0.05).

RESULTSThe linear, volumetric, and geometric deviations were -0.03 ± 0.48 mm, -5.4 ± 2.8%, and 0.117 ± 0.018 mm for NewTom VG 0.15 mm group; -0.45 ± 0.42 mm, -4.5 ± 3.4%, and 0.116 ± 0.014 mm for NewTom VG 0.30 mm group; and -0.93 ± 0.40 mm, -4.8 ± 5.1%, and 0.194 ± 0.117 mm for VATECH DCTPRO 0.30 mm group, respectively. There were statistically significant differences between groups in terms of linear measurement (P < 0.001), but no significant difference in terms of volumetric measurement (P = 0.774). No statistically significant difference were found on geometric measurement between NewTom VG 0.15 mm and NewTom VG 0.30 mm groups (P = 0.999) while a significant difference was found between VATECH DCTPRO 0.30 mm and NewTom VG 0.30 mm groups (P = 0.006).

CONCLUSIONSThe 3D reconstruction from CBCT data can achieve a high linear, volumetric, and geometric accuracy. Increasing voxel resolution from 0.30 to 0.15 mm does not result in increased accuracy of 3D tooth reconstruction while different systems can affect the accuracy.

Cone-Beam Computed Tomography ; methods ; Humans ; Image Processing, Computer-Assisted ; methods ; Imaging, Three-Dimensional ; methods ; Tooth ; anatomy & histology ; pathology