Distribution of interleukin-2 receptor α-chain and cells expressing major histocompatibility complex class II antigen in chronic human periapical lesions

In situ distribution of CD2⁺ T-lymphocytes, CD4⁺ and CD8⁺ T-cell subsets, CD14⁺ macrophages, interleukin-2 receptor α-chain (IL-2Rα) and class II major histocompatibility complex antigen (major histocompatibility complex class II, HLA-DR) expressing cells were determined in 14 chronic human periapical granulomas by imrnunohistochemical method using monoclonal antibodies. CD2⁺ lymphocytes were rather evenly distributed within the classical granulation tissue and comprised 55% of the mononuclear cells. Macrophages were distributed all over the periapical area, but their proportion was much less than that of T lymphocytes. Both small, lymphocyte-like mononuclear cells and larger mononuclear cells resembling macrophages displayed mild to strong circumferential staining with the anti-HLA-DR antibody. The majority of lymphocytes expressed IL-2Rα indicating the activated state of T cells within the lesion.     

Genetic studies of syndromes with severe periodontitis and palmoplantar hyperkeratosis

The Papillon-Lefevre and Haim Munk syndromes are characterized by the presence of both palmoplantar hyperkeratosis (PPK) and severe early onset periodontitis. It is the early onset periodontal disease component that distinguishes these from other more common forms of PPK. It has been proposed that the periodontal disease component may be a casual association in individuals with PPK. Genetic syndromes with palmoplantar keratosis and severe early onset periodontitis may be due to specific bacterial infections in individuals with PPK. Recently, keratin gene mutations have been identified in several conditions typified by palmoplantar keratosis. The present study sought to test the hypothesis that a keratin gene defect similar to those previously identified in other PPK conditions is responsible for the Haim Munk and the Papillon-Lefevre syndromes. We have performed genetic linkage studies to test for linkage between polymorphic DNA loci within 2 cytokeratin gene families and the disease phenotype in Haim Munk syndrome and Papillon-Lefevre syndrome. Families with individuals segregating for the Haim Munk syndrome and the Papillon-Lefevre syndrome were examined to determine disease status, and genotyped for microsatellite DNA markers closely linked to the acidic (type I) and the basic (type II) cytokeratin genes on chromosomes 12 and 17. Genotype data were evaluated for microsatellite allele homozygosity in affected individuals. Results of these preliminary genetic studies suggest that the gene defect in Haim Munk syndrome is not due to a gene defect in either the type I or the type II keratin gene clusters. These findings suggest that Haim Munk syndrome may be genetically distinct from other more common forms of PPK that have been linked to the cytokeratin gene families, and suggest that mutations in genes other than keratin genes are responsible. Additional family studies are needed to confirm these preliminary findings.     

Chronodynamic evaluation of the stages of osseointegration in zirconium laminar implants

Osteogenesis occurs throughout all stages in life, due to both bone turnover and reparative processes. Thus, osseointegration (OI) can be described as the final step in a cascade of processes involved in bone healing in relation to implants. Ten groups of 5 Wistar rats each (mean = 90 g b.w.) were used. Under ether anesthesia a zirconium laminar implant was placed in the tibia following the method previously described by our laboratory (Cabrini et al Imp Dent 2:264-7, 1993). The animals were killed at Ohs, and 1, 2, 3, 6, 7, 10, 12, 14, and 60 days post-implantation. Tibiae were resected, radiographed and processed for their embedding in methyl methacrylate. Three sections, perpendicular to the major axis of the tibia, were obtained per implant and histologic and histomorphometric studies were carried out. Volume occupied by blood clot, woven bone, percentage of OI and OI bone tissue thickness, were determined. Histologic and histomorphometric studies as function of time revealed: a) at 6 days the presence of non-osseointegrated woven bone around the device is evident increasing in volume from 7 to 10 days post-implantation, and disappearing from day 12 to 14., b) at 14 days after implantation lamellar bone formation on the surface of the zirconium implants (OI) is noticeable. Additional bone growth is observed after 60 days. This study enables quantification of peri-implant reparative process response in an unloaded, necrotic trabeculae free model showing, in the different phases of the osseointegration process, the role of the blood clot and of the appearance and disappearance of woven bone and the final stages of osseointegration. Further investigation will allow comparison of results obtained under the effect of local and/or systemic factors that might affect osseointegration.     

The early development of palatal rugae in the rat

The palatal rugae in rats are contained in two of three zones of morpho-differentiation and develop around the time of palatal closure. Previous studies in humans and pigs have been based on crown-rump lengths but now controlled breeding in rats has allowed exact timing to be established. Twenty-nine female DB IX rats were fertilized and sacrificed in a controlled procedure and foetuses processed for light microscopy and SEM. Serial sagittal sections were made and stained with haematoxylin and eosin and Verhoef's stains. At day 13 the palate was open and no rugae were visible. At day 14 the palatal shelves had started to migrate medially and the ante-molar rugae appeared. At day 15 the palatal shelves were touching and the inter-molar rugae became visible, and at day 16 fusion was all but complete and the definitive rugal pattern established. The development and differentiation is more advanced than in humans and it is concluded that the rugae probably have a role to play in the oral function of animals whereas in humans they are becoming attenuated and the development timetable is retarded because of redundancy.     

The evaluation of horizontal reference planes of adult Chinese in natural head position.

A group of 112 adult females (average age 25.66) and 104 adult males (average age 25.62) were subjected to cephalometric evaluation in their natural head position. No significant differences were found in the nasionsella (SN) plane, Frankfort horizontal (FH) plane or palatal planes between male and female subjects. The SN plane was found to be located at 7.26 degrees above the true horizontal on the average, and the FH plane differed on the average 1.92 degrees from the true horizontal with the line diverging forward and upward. The palatal plane was found to be located in a downward and forward direction at 1.17 degrees from the true horizontal plane on the average. The orbitale (Or) was found to be located at 2.34 mm on the average above the true horizontal plane depicted from the porion (Po) in this study, which implies that the racial characteristic of a high zygomatic bone in Chinese may have some influence upon the position of Or, and this should be taken into consideration when the FH plane is used as the true horizontal during face bow transfer. The mandibular plane (MP) angle, occlusal plane (OP) angle and the gonial angle (GA) of males were found to be smaller than those of females, with a significant difference at the level of P less than 0.001, P less than 0.01 and P less than 0.01, respectively. The upper facial divergent angles of males and females were quite similar, as reflected by the similarity in the SN-FH angles and SN-PP angles between the sexes A significant difference was found to exist in the lower facial divergent angles between males and females. The SN-MP angle, PP-OP angle and PP-MP angle were all significantly smaller in males, with a P less than 0.001. The OP-MP angle was also smaller in males with P less than 0.05.     

Planning, implementation, and evaluation of AIDS education programs for dentists

Because many dentists were trained before HIV disease was recognized and its implications for dentistry understood, there is a need for effective continuing education programs about the disease for health professionals. Unfortunately, much of the continuing professional education about AIDS in the last few years has been poorly evaluated and the value of continuing education itself has increasingly been called into question. In order to clarify how continuing educational efforts can be designed and evaluated, we report on our continuing educational projects and research which culminated in research on a nationwide educational intervention about AIDS for dentists. We outline and evaluate the steps taken in designing both the intervention and the research. The strengths and weaknesses of the design are discussed and suggestions made about how the design could be improved.     

Dose-responsive characteristics of meperidine sedation in preschool children

Using double-blind conditions, 60 uncooperative and fearful preschool children (24-66 months) received intramuscular injections of meperidine 0.25, 0.50, 1.00 mg/lb or placebo prior to restorative dental treatment. Behavior was assessed by the dentist and an independent observer during five specific treatment procedures. Behavioral ratings found meperidine to be an effective sedative, with 0.50 mg/lb and 1.00 mg/lb being significantly more effective than placebo (P less than 0.05, Kruskal-Wallis). Children receiving 1.0 mg/lb of meperidine had significantly more nausea and vomiting than patients receiving lower doses of the drug (P less than 0.05, Chisquare). Physiologic monitoring demonstrated that the highest dose of meperidine was associated with transient drops in arterial oxygen saturation. Meperidine sedation was found to be more effective for older children (37-66 months) and for children initially rated as being only moderately uncooperative and fearful.     

Aneurysmal bone cyst of the mandible--a case report

Aneurysmal bone cysts originating in the craniofacial region have seldom been reported in Taiwan. A case of aneurysmal bone cyst arising in the right mandible of a 15-year-old Chinese boy was presented with both the roentgenographic and microscopic findings. In view of the high recurrent rate and the large destructive mandibular lesion, segmental resection with immediate bone grafting for reconstruction and a conscientious follow up regimen was employed. The etiology and pathogenesis of this interesting lesion remained unclear but several theories were reviewed and the differential diagnosis of this lesion was also discussed. Furthermore, immunoperoxidase staining for Factor VIII related antigen was performed to help differentiate between the aneurysmal bone cyst and a central hemangioma and then to elucidate the pathogenesis of the former.     

Adenoid cystic carcinoma of the palate in a 9-year-old boy

Malignant tumors of salivary glands in children are extremely rare. A case of an adenoid cystic carcinoma affecting the palate in a 9-year-old child is described. This tumor has not previously been reported as affecting the minor salivary glands among patients in this age group.