Ameloblastoma with mucous cells: A clinicopathological, BRAF mutation, and MAML2 rearrangement study.

OBJECTIVES: To investigate the clinicopathological features, BRAF V600E mutation, and MAML2 rearrangement of ameloblastoma with mucous cell differentiation. MATERIALS AND METHODS: Five cases of ameloblastoma with mucous cell differentiation were retrospectively studied. Clinicopathological features, BRAF V600E mutation, and MAML2 rearrangement were analyzed. Follow-up information was available for all cases. RESULTS: Of five cases, two cases were male and three were female, aged 18-55 years. Four cases were located in the mandible and one case in the maxilla. Histologically, four of the five cases (80%) presented with cystic features and three of the five cases (60%) with varying degrees of squamous metaplasia. The mucous cells were located in the epithelial islands or the luminal aspect of the cystic cavities. The BRAF V600E mutation was found in three of five cases (60%). All the cases showed no MAML2 rearrangement. Two cases were recurrent lesions, and one case had a local recurrence during the follow-up. CONCLUSIONS: Ameloblastoma with mucous cell differentiation is closely related to the cystic features, squamous metaplasia, and shows a high prevalence of BRAF V600E mutation. The absence of MAML2 rearrangement reveals that ameloblastoma with mucous cell differentiation and central mucoepidermoid carcinoma (MEC) are two distinct tumor entities.

Self-Assembling Nonconjugated Poly(amide-imide) into Thermoresponsive Nanovesicles with Unexpected Red Fluorescence for Bioimaging.

Nonconjugated red fluorescent polymers have been increasingly studied to improve the biocompatibility and penetration depth over conventional fluorescent materials. However, the accessibility of such polymers remains challenging due to the scarcity of nonconjugated fluorophores and lacking relevant mechanism of red-shifted fluorescence. Herein, we discovered that the combination of hydrogen bonding and π-π stacking interactions provides nonconjugated poly(amide-imide) with a large bathochromic shift (>100 nm) from blue-green fluorescence to red emission. The amphiphilic PEGylated poly(amide-imide) derived from in situ PEGylation self-assembled into nanovesicles in water, which isolated the aminosuccinimide fluorophore from the solvents and suppressed the hydrogen bonds formation between aminosuccinimide fluorophores and water. Therefore, the fluorescence of PEGylated poly(amide-imide) in water was soundly retained. Furthermore, the strong hydrogen bonding and hydrophobic interactions with water provided PEGylated poly(amide-imide) with a reversible thermoresponsiveness and presented a concentration-dependent behavior. Finally, accompanied by the excellent biostability and photostability, PEGylated poly(amide-imide) exhibited as a good candidate for cell imaging.

Low Annexin A1 expression predicts benefit from induction chemotherapy in oral cancer patients with moderate or poor pathologic differentiation grade.

BACKGROUND: The benefit of induction chemotherapy in locally advanced oral squamous cell carcinoma (OSCC) remains to be clearly defined. Induction chemotherapy is likely to be effective for biologically distinct subgroups of patients and biomarker development might lead to identification of the patients whose tumors are to respond to a particular treatment. Annexin A1 may serve as a biomarker for responsiveness to induction chemotherapy. The aim of this study was to investigate Annexin A1 expression in pre-treatment biopsies from a cohort of OSCC patients treated with surgery and post-operative radiotherapy or docetaxel, cisplatin and 5-fluorouracil (TPF) induction chemotherapy followed by surgery and post-operative radiotherapy. Furthermore we sought to assess the utility of Annexin A1 as a prognostic or predictive biomarker. METHODS: Immunohistochemical staining for Annexin A1 was performed in pre-treatment biopsies from 232 of 256 clinical stage III/IVA OSCC patients. Annexin A1 index was estimated as the proportion of tumor cells (low and high, <50% and ≥50% of stained cells, respectively) to Annexin A1 cellular membrane and cytoplasm staining. RESULTS: There was a significant correlation between Annexin A1 expression and pathologic differentiation grade (P=0.015) in OSCC patients. The proportion of patients with low Annexin A1 expression was significantly higher amongst those with moderate/poorly differentiated tumor (78/167) compared to those with well differentiated tumor (18/65). Multivariate Cox model analysis showed clinical stage (P=0.001) and Annexin A1 expression (P=0.038) as independent prognostic risk factors. Furthermore, a low Annexin A1 expression level was predictive of longer disease-free survival (P=0.036, HR=0.620) and locoregional recurrence-free survival (P=0.031, HR=0.607) compared to high Annexin A1 expression. Patients with moderate/poorly differentiated tumor and low Annexin A1 expression benefited from TPF induction chemotherapy as measured by distant metastasis-free survival (P=0.048, HR=0.373) as well as overall survival (P=0.078, HR=0.410). CONCLUSIONS: Annexin A1 can be used as a prognostic biomarker for OSCC. Patients with moderate/poorly differentiated OSCC and low Annexin A1 expression can benefit from the addition of TPF induction chemotherapy to surgery and post-operative radiotherapy. Annexin A1 expression can potentially be used as a predictive biomarker to select OSCC patients with moderate/poorly differentiated tumor who may benefit from TPF induction chemotherapy.

Malignant hemangiopericytoma of the condyle.

Hemangiopericytoma (HPC) is an uncommon vascular tumor arising from pericytic cells with variable malignant potential. Primary HPCs of the bone are extremely rare; however, involvement of the condylar process has not been reported. We presented a 21-year-old female patient with low-grade malignant HPC in the right mandibular condyle. Clinical examination and imaging findings revealed a well-defined soft mass, encapsulating the mandibular condyle from behind. The lesion and mandibular condyle were removed simultaneously; then, the costochondral graft was used to reconstruct the defect. Histopathologic examinations of the specimen confirmed the diagnosis. After 2 years of follow-up, the patient is free of disease, and mouth opening returned to normal.

[Effect of Er:YAG laser in pulp revascularization in miniature pigs].

PURPUSE: To compare the effectiveness of Er:YAG laser and Ca(OH)2 in pulp revascularization in miniature pigs. METHODS: The second and third premolars of three 14-15-month-old miniature pigs were randomly divided into three groups: laser group, medication group and negative control group. After establishment of pulp necrosis model in each group, the negative control group had no more procedures, while the laser group and medication group were treated with pulp revascularization. Intracanal antisepsis operation was conducted using Er:YAG laser in laser group and Ca(OH)2 in medication group. The maxillary first premolars, as a positive control group, were left untreated and grew naturally. Three months after surgery, X-ray and cone-beam CT(CBCT) were taken. The animals were sacrificed, and the teeth were used to make H-E staining sections. The development of the teeth and the histological manifestations in the root canals of both groups were compared and evaluated by radiographic and histological assessment. SPSS 24.0 software package was used for statistical analysis of the data. RESULTS: Radiographic results showed that 3 months after surgery, apical foramen was closed in the laser group and the medication group. It also showed that intracanal calcification, and some specimens manifested root absorption. There was no significant difference between the two groups in the aspects of increase of root length, root thickness, or decrease of apical foramen size(P>0.05). Histological results showed that there was dentin-like and cementum-like tissue deposition along the root canal walls; apical closure was apparent; and fibrous connective tissue and cementum-like tissue or bone-like tissue formation in the root canal space were evident in the laser group and the medication group 3 months after surgery. There was no significant difference in the histological findings between the two groups(P>0.05). CONCLUSIONS: Er: YAG laser can be applied to pulp revascularization in miniature pigs, and the effect is equivalent to that of intracanal medication using Ca(OH)2.

Malignant transformation of oral verrucous leukoplakia: a clinicopathologic study of 53 cases.

BACKGROUND: Oral verrucous leukoplakia (VL) is one of the non-homogenous oral leukoplakias. The objective of this study was to investigate the clinicopathologic features of VL and identify the clinicopathologic risk factors that might be associated with VL malignant transformation from China. METHODS: Among 1541 patients with oral leukoplakia, a total of 53 patients with clinical and histopathologic diagnosis of VL between 1996 and 2009 were reviewed retrospectively in our hospital. RESULTS: Of the 53 patients, 11 (20.8%) with VL were observed to develop cancer in the study period. The average age at diagnosis was 59.8 years with a male/female ratio of 1.7:1. Tongue was the predominant site (41.5%). Multivariate regression analysis revealed that the elderly patients (>65 years old) were associated with 8.36-fold [95% confidence interval (95% CI), 1.45-48.09; P = 0.017] increased risk of malignant transformation compared with the non-elderly patients. The lesion located on gingiva was associated with 20.81-fold (95% CI, 1.94-222.80; P = 0.012) increased risk of malignant transformation compared with tongue. However, the gender, smoking, alcohol intake, and epithelial dysplasia were not risk factors. CONCLUSION: Clinicopathologic features of VL in China were elucidated. The utilization of age and lesion site at diagnosis as significant factors for evaluating malignant transformation risk in patients with VL was suggested. Further studies are required to investigate the roles of the potential risk factors in the VL malignant transformation.

Giant cell-rich osteosarcoma or giant cell reparative granuloma of the mandible?

Giant cell-rich osteosarcoma (GCRO) is a rare subtype of osteosarcoma, and no literature has reported occurrence in the mandible region up to now. In this article, we report a case of GCRO originating from the mandible in a 67-year-old woman who presented a history of painless mass located in the left side of the mandible after teeth extraction. The curettage biopsy histologic diagnosis is giant cell reparative granuloma before mandibulectomy surgery, but panoramic radiograph revealed an osteolytic lesion. The tumor was completely resected with segmental mandibulectomy and soft tissue with postoperative histologic diagnosis of GCRO. The free fibula osteomyocutaneous flap was performed to reconstruct the defect of the mandible and gingival mucosa. The patient received postoperative radiotherapy and chemotherapy. The 1-year follow-up situation is fine.

Melanotic Neuroectodermal Tumor of Infancy: A Clinicopathological and BRAF V600E Mutation Study of 11 Cases.

PURPOSE: To investigate the clinicopathological features and BRAF V600E mutation of melanotic neuroectodermal tumor of infancy (MNTI). MATERIALS AND METHODS: Eleven cases of MNTI diagnosed at the Department of Oral Pathology were collected. Clinicopathological characteristics were obtained from the medical records. Immunostaining was performed by immunohistochemistry (IHC). Amplification-Refractory Mutation System-qPCR (ARMS-qPCR) and Sanger Sequencing were used to detect BRAF V600E mutation. RESULTS: Of the 11 cases, 3 cases were female and 8 cases were male. The mean age of the first symptoms was 3.2 months (range: 1 to 6 months). Ten cases (90.9%) located in maxilla but only one (9.1%) in mandible. Most of the cases demonstrated well-defined mass with lytic bone destruction and tooth germ affecting radiologically. Histologically, MNTI was consisted of large polygonal melanin-producing epithelioid cells and small round neuroblast-like cells which arranged in irregular alveolar, tubuloglandular and fissured architecture. The epithelioid cells expressed Vim, Pan-CK, NSE and HMB45, while the smalls cells expressed Syn, NSE and scattered Vim. Most cases showed low Ki-67 index (range: <1% to 50%). None of the MNTI cases showed BRAF V600E mutation. Most cases were treated with enucleation (45.4%) or curettage (36.4%). Among the 11 cases, 6 cases had follow-up information, and 2 cases had recurrence lesions after surgery. CONCLUSION: MNTI, an extremely rare tumor, mainly affects male infants with strong preference for maxilla. Distinct histopathological features and immunohistochemical profile are helpful to distinguish from other melanin-containing tumors and small round cell tumors. No BRAF V600E mutation in MNTI is detected in the present study and needs further investigations. The factors that contribute to the local recurrence of MNTI are controversial, but the close follow-up for the patients is recommended.

Primary pseudomyogenic hemangioendothelioma of right maxilla: a case with immunohistochemistry and FOSB rearrangement study.

OBJECTIVE: Primary pseudomyogenic hemangioendothelioma (PMH) of bone is an extremely rare vascular neoplasm. We present here a case of primary PMH occurring in the maxilla. STUDY DESIGN: A 34-year-old man was referred to our hospital for treatment because of possible recurrence after surgery and chemotherapy of a right maxillary malignant tumor. Morphologic features, immunophenotypes, and FOSB gene rearrangement status of the surgically sectioned sample were assessed by hematoxylin-eosin staining, immunohistochemistry, and fluorescence in situ hybridization, respectively. RESULTS: Morphologically, the tumor cells were arranged in a loose fascicular and sheet-like manner, with a large number of reactive woven bones forming. The most striking feature was the presence of epithelioid cells with abundant brightly eosinophilic cytoplasm, which resembled the rhabdomyoblast in appearance. The tumor was diffusely positive for AE1/AE3, CD31, erythroblast transformation-specific transcription factor, and Friend leukemia integration 1; negative for CD34, CAM5.2, epithelial membrane antigen, and desmin; and had retained expression of integrase interactor 1. The tumor harbored FOSB rearrangement. No distant metastasis was found during the follow-up period (18 months). CONCLUSIONS: To the best of our knowledge, this case represents the first report of PMH arising in the maxilla. The distinct morphologic features, immunophenotypes, and FOSB rearrangement could help achieve precise diagnosis and prevent misdiagnosis of mimics with overlapping features.

[Determination of life elements in hair and urine with brick-tea fluorosis in Inner Mongolia by ICP-OES].

In brick-tea fluorosis affected areas XiLinHot city in Inner Mongolia, herdsmen who like drinking a large amount of brick tea in everyday life and Han habitants rarely drinking brick tea as control group were enrolled, and their hair and urine were sampled. The concentrations of Ca, Mg, K, Al, P, Cu, Zn and Fe in hair and urine were detected using ICP-OES. The RSDs of the method were between 2.32% and 8.03%, and the analytical results of the hair reference samples were consistent with the certified values. The results showed that the contents of Al, Mg and K in hair, and contents of Al and Ca in urine of herdsmen who were accustomed to drinking brick tea were obviously higher than those in control group (P<0.05), while the contents of K in urine of herdsmen who were accustomed to drinking brick tea was lower than those in control group (P<0.05), and other elements did not have statistic significance (P>0.05). Chronically drinking brick tea probably brings metabolic disorder of Ca and Al in human body, and the interaction mechanism of life elements in brick-tea fluorosis should be further studied.

[Construction of clinical practice system of oral pathology for long-term program students in stomatology].

PURPOSE: To construct clinical practice system, making up for the shortcomings in the instructional framework of oral histology and pathology, promoting the integration of theory and clinical practice, and enhancing teaching quality of long-term students of stomatology. METHODS: Laying down clinical practice plans and formulating technical operation criteria for pathological experiments, constructing a complete database and training high-level teachers, and evaluating through the following three aspects: practice assessment, teacher-student symposium and questionnaire survey. RESULTS: After completing the clinical practice, the students got the average score of 89.37. In questionnaire survey, the students generally expressed that they had a better understanding of the specialized characteristics and routine skills of the speciality, and improved their practical ability, thus stimulating their interest in self-directed learning. CONCLUSIONS: The construction and practice of clinical practice system of oral histology and pathology can effectively improve the educational objectives and teaching quality of this discipline, which will play a positive role in scientific research and future medical work of long-term students majoring in stomatology.

Computed tomographic features of adenoid cystic carcinoma in the palate.

BACKGROUND: To evaluate the computed tomographic features and create a prediction model for clinical diagnosis of adenoid cystic carcinoma (ACC) in the palate with intact mucosa. METHODS: From March 2016 to May 2018, 102 patients with palatal tumors and intact mucosa, including 28 patients with a pathological diagnosis of ACC after surgery, were enrolled in this study. The patients' clinical symptoms, computed tomographic features and pathological diagnoses were recorded and analyzed. Independent predictors of ACC were determined by using univariate analysis and multivariate logistic regression, and the discrimination and calibration of the prediction model was evaluated, and internal validation was performed. RESULTS: Univariate analysis of patients showed that ACC patients were more likely than non-ACC patients to be older (P = 0.019); to have palatine bone destruction (P<0.001) and greater palatine foramen (GPF) enlargement (P<0.001); to have involvement of the pterygopalatine fossa (P<0.001), foramen rotundum (P<0.001), nasal cavity (P<0.001) and maxillary bone (P<0.001); and to have numbness (P = 0.007) and pain (P<0.001). Multivariate logistic analysis showed that age and GPF enlargement were independent predictors of ACC in palatal tumors. The diagnostic prediction model showed good discrimination and calibration, as evaluated by the area under the receiver operating characteristic curve (0.98) and the Hosmer-Lemeshow goodness-of-fit test (P = 0.927). CONCLUSIONS: The palate ACC prediction model based on age and GPF enlargement shows excellent discrimination with no evidence of poor calibration. Older patients with palatal tumors and intact mucosa should be considered for ACC when they have GPF enlargement.

Clinical and pathologic analyses of tuberculosis in the oral cavity: report of 11 cases.

OBJECTIVE: The aim of this study was to analyze tuberculosis (TB) in the oral cavity according to clinical appearance, clinical differential diagnosis, treatment, and outcome. STUDY DESIGN: We enrolled 11 patients with TB in the oral cavity between November 2012 and November 2016. Glossal lymphoid TB was excluded. Clinical symptoms, auxiliary examinations, treatments, and outcomes were recorded and analyzed. RESULTS: The study population comprised 6 men and 5 women, with a mean age of 59 years. Five patients presented with ulcer, 5 with a mass, and 1 with osteomyelitis. Excisional biopsy was performed in 3 patients, mass resection in 7, and curettage of mandibular lesion in 1. After pathologic diagnosis of TB in the oral cavity in 8 patients; 6 of them underwent purified protein derivative examination, and 4 of them had positive results and received drug therapy. The mean follow-up period was 24.9 months, and there was no recurrence. CONCLUSIONS: TB in the oral cavity is rare and has no specific clinical features. Pathology, acid-fast staining, polymerase chain reaction, and DNA testing for Mycobacterium tuberculosis are useful for final diagnosis. Surgery is recommended as the treatment of choice to achieve good clinical outcomes.

[Improving the teaching quality by multiple tools and technology in oral histopathology experimental course].

PURPOSES: Oral histopathology is a course which needs to be combined with theory and practice closely. Experimental course plays an important role in teaching oral histopathology. Here, we aim to explore a series of effective measures to improve the teaching quality of experimental course and tried to train observation, thinking, analysis and problem solving skills of dental students. METHODS: We re-edited and updated the experimental textbook "guidelines of experimental course of oral histopathology", and published the reference book for experimental course--"color pocket atlas of oral histopathology: experiment and diadactic teaching". The number of clinicopathological cases for presentation and class discussion was increased, and high-quality teaching slides were added and replaced the poor-quality or worn out slides. We established a variety of teaching methods based on the internet, which provided an environment of self-directed learning for dental students. Instead of simple slice-reading examination, a new evaluation system based on computer was established. RESULTS: The questionnaire survey showed that the students spoke positively on the teaching reform for experimental course. They thought that the reform played a significant role in enriching the teaching content, motivating learning interest and promoting self-study. Compared with traditional examination, computer-based examination showed a great advantage on mastering professional knowledge systematically and comprehensively. CONCLUSIONS: The measures adopted in our teaching reform not only effectively improve the teaching quality of experimental course of oral histopathology, but also help the students to have a clear, logical thinking when facing complicated diseases and have the ability to apply theoretical knowledge into clinical practice.

[Application of diversified teaching methods to improve the teaching effects in the course of oral histology and pathology].

Oral histology and pathology is one of the most important courses in stomatological education which works as a bridge between basic medical courses and clinical courses of oral science. The knowledge of oral histopathology may help the students to correctly understand the histogenesis and development of oral diseases and provide the information for correct treatment and prevention. In order to make the students grasp the necessary basic theories, increase the interest in learning, and improve the teaching effect, we explored a diversified teaching system which included diverse teaching modes, online courses and courseware construction. The application of this system offered the interaction between students and teachers and combination of classes with the internet, and made the boring pathological knowledge be associated with clinical practice. These diversified teaching methods had been used in practice and obtained good teaching results.

Bioevaluation study of 32P-CP-PLLA particle brachytherapy in a rabbit VX2 lung tumor model.

OBJECTIVE: The purpose of this study was to investigate the therapy effects of intratumoral administration of (32)P-CP-PLLA particles in a rabbit VX2 lung tumor model. METHODS: 16 rabbits with tumors were randomly divided into 4 groups. 4 rabbits served as untreated controls, and others received intratumoral administration of (32)P-CP-PLLA particles with CT guidance. The total radioactivities in treated groups were as follows: a low activity was 93 MBq (n=4) (group 1), a medium activity was 185 MBq (n=4) (group 2) and a high activity was 370 MBq (n=4) (group 3). Brachytherapy treated VX2 tumors underwent (18)F-FDG PET/CT at 0 day, 3 day, 7 day and 14 day postinjection. In control group, (18)F-FDG PET/CT images were acquired at the same time points but without any treatment. Bremsstrahlung SPECT images were performed at 14 days after intratumoral brachytherapy in treated groups. After Bremsstrahlung SPECT and last (18)F-FDG PET/CT imagings, the rabbits were euthanized and the tumors were removed for histological examination. RESULTS: Bremsstrahlung SPECT images study indicated that there was no leakage of (32)P out of the injection site at 14 days after treatment. Compared with the control, the tumor volumes in treated groups significantly decreased, and (32)P-CP-PLLA particle produced a reduction in maximum or mean SUV of VX2 tumor (p<0.05). The percentage changes in maximum and mean SUV gradually decreased in group 1 and group 2 from day 3 to day 14 (p<0.05). A transient increase in (18)F-FDG accumulation at group 3 occurred due to the inflammatory reaction elements. Activity dependence was seen in HE and PCNA staining after 14 days treatment among three treated groups (p<0.05). CONCLUSIONS: Our data suggested that (32)P-CP-PLLA particle localized on the injecting sites. This novel brachytherapy device efficiently suppressed the growth of the VX2 tumors implanted in the rabbit.

Clinical analysis of 120 cases of intraoral lymphoepithelial cyst.

OBJECTIVE: The aim of this study was to analyze a single institution's experience in the clinical management of intraoral lymphoepithelial cyst (LEC). STUDY DESIGN: From 1993 to 2010, a total of 120 consecutive patients with intraoral LEC underwent surgery and were retrospectively investigated regarding its clinical appearance, clinical differential diagnosis, treatment, and prognosis. RESULTS: Of the 120 patients, 37 were male and 83 female, their ages ranging from 2 to 75 years with a mean of 44.1 years. The most common locations were the tongue (50%) and floor of mouth (38.3%). The course of disease ranged from 2 months to 10 years with a mean of 8.0 months, and 75.8% of the patients had a course of disease <6 months. Routine laboratory examinations were within normal limits. All patients underwent complete surgical removal of the lesions. During the follow-up period, no lesion recurrence occurred, and the quality of life of each patient was good. CONCLUSIONS: The clinical characteristics of intraoral LEC are not specific and may be confused with other intraoral lesions. The first choice of treatment is surgical excision, which results in a good prognosis.

Oral melanotic macule and primary oral malignant melanoma: epidemiology, location involved, and clinical implications.

BACKGROUND: Oral malignant melanoma must be differentiated from melanotic macule. STUDY DESIGN: Retrospective review of 2 series of oral melanotic macule (n = 52) and oral melanoma (n = 130) were conducted to investigate the epidemiology and location involved and assess their differences. RESULTS: The mean age of oral melanotic macule patients was 47.3 years, with female:male ratio 2.1 and the lower lip being the predominant location. The mean age of oral melanoma patients was 53.8 years, with no observed sex predilection and the main locations being palate and gingiva. Differences between the 2 cohorts in age (P = .006), gender (P = .014), and lesion site (P < .001) were noted. In this review, 1 case of oral melanotic macule was found to subsequently develop into melanoma. CONCLUSIONS: Oral melanotic macule may possess malignant potential. Biopsy is recommended to differentiate oral melanoma from melanotic macule for male patients >60 years old with suspected melanotic macule lesion located on the palate.

[Comparison of the attachment and growth characteristics between human junctional epithelium and oral epithelium cells].

OBJECTIVE: To compare the attachment and growth characteristics between human junctional epithelium (JE) and oral epithelium cells. METHODS: The healthy JE biopsies were derived from the human teeth extracted due to impaction or orthodontic purpose. Enzyme digestion was used to isolate JE cells, which were then cultured in DKGM. The co-culture model of JE cell-tooth slice was built up by adding 3 decalcification cementum slices (5 mm x 3 mm x 1 mm) into sterilized plate containing 1 ml of JE cells (5 x 10(8)/L), 21 slices all together,and incubated in an atmosphere containing 5% CO2 at 37 degrees C for 1-14 days. The attachment structure was observed under transmission electron microscope, and the OE cells was used as control. RESULTS: The human JE cells were polymorphous in shape and CK19 positive, while OE cells were consisted of equal and closely packed epithelial-like cells in a paving stone arrangement, and CK19 was only strained in a few cells. There were a few cells in JE-slice when co-cultured for 1-3 days, and electron dense plaques on the JE cell surface of the attached slice were observed at 9 days, and 2-3 layer of JE cells and hemidesmosome-like structure formed within 11-14 days. There were more OE cells within 1-3 days, electron dense plaques appeared at 7 days, and stratified epithelium and hemidesmosome-like structure formed in OE-slice at 9 days. CONCLUSIONS: The cultured JE cells were immature and lower differentiated epithelial cells which were different from OE cells. Under the same condition the growth and attachment of JE cells on the cementum slice surface were slower than that of OE cells. Their attachment strength needs further study.

[Study on odontal & periodontal tissue of guinea pigs, dogs and monkeys].

PURPOSE: To evaluate the different application of different experimental animals in studies of periodontal diseases. METHODS: The odontal and the periodontal tissues of guinea pigs, dogs and monkeys were studied by gross specimen, X ray and histological observation. RESULTS: The most suitable sites of guinea pigs for periodontal study is incisor just because of their small oral fissure, but the keratinized epithelium of gingival sulcus may affect their inflammatory reaction. As the occurring of spaces from the 3rd to 5th tooth of dogs, artificial intrabony pocket can be made, and their thick root canals are suitable for pulp and periapical study. The monkeys are the ideal experimental animals due to their similarities to human, but it is too expensive to be widely used. CONCLUSION: Each kind of animal has their own characteristics. The key is to select experimental animal according to the objective of our different studies.