Biphasic alloplastic graft used to preserve the dimension of the edentulous ridge: an experimental study in the dog.

BACKGROUND: Loss of teeth results in marked qualitative and quantitative alterations of the alveolar process at the edentulous site. It was observed that a graft comprised of bovine bone mineral placed in the fresh extraction socket delayed tissue modeling, but preserved the dimension of the ridge at edentulous sites. OBJECTIVE: To analyze the influence of a biphasic synthetic graft on tissue modeling and remodeling during healing of extraction wounds. MATERIAL AND METHODS: Five beagle dogs were used. Two premolars in the maxilla and two in the mandible were included. Full thickness flaps were elevated and the distal roots were removed. An alloplastic graft (BPCAP; α-TCP core coated with nanocrystalline biomimetic hydroxyapatite) embedded in porcine collagen was placed to fill the fresh extraction socket of the premolar sites. Flaps were replaced to cover the entrance of the extraction sockets during early healing. The extraction and grafting procedures were scheduled to allow for the study of 1, 2, and 3 months socket healing. The biopsies from the maxillary sites were decalcified, embedded in paraffin, and stained to allow the study of various aspects of hard tissue formation. The biopsies from the mandibular sites were processed for ground sectioning and used to evaluate alterations of ridge dimensions after 3 months of socket healing. RESULTS AND CONCLUSION: It was documented that the biphasic alloplastic graft did not undergo marked resorption during tissue modeling and remodeling, but allowed large amounts of bone to form within the post-extraction site. Grafting the experimental sites with this biomaterial furthermore counteracted ridge resorption that otherwise occurs following tooth extraction.

B-1a cells and plasma cells in periodontitis lesions.

BACKGROUND AND OBJECTIVE: Host response mechanisms in periodontal tissues are complex and involve numerous systems of interactions between cells. The B-cell lineage seems to predominate in chronic periodontitis lesions. The aim of the present investigation was to study the correlation between inflammatory cells and some functional markers in gingival lesions obtained from subjects with severe chronic periodontitis. MATERIAL AND METHODS: Thirty-eight Caucasian subjects volunteered to take part in the study. A gingival biopsy from one randomly selected diseased proximal site (probing pocket depth > 6 mm and bleeding on probing positive) was obtained from each patient. Immunohistochemical preparation was used to identify inflammatory cells and functional markers. Correlations between the different percentages of cell markers were analyzed by pairwise correlation. RESULTS: B cells (B-1a and B-2 cells) occurred in larger proportions than T cells and plasma cells. A statistically significant correlation was found between the percentage of B-1a cells and plasma cells and between all B lymphocytes and plasma cells. About 60% of B lymphocytes exhibited autoreactive features. CONCLUSION: It is suggested that B-1a cells constitute a significant part of the host response in periodontitis lesions and that plasma cells may develop from both B-2 and B-1a cells.

Soft tissue healing at titanium implants coated with type I collagen. An experimental study in dogs.

OBJECTIVE: To analyse the soft tissue healing at titanium implants coated with type 1 collagen. MATERIAL AND METHODS: Six dogs were used. The mandibular pre-molars and the three anterior maxillary pre-molars were extracted. Three months later mucoperiosteal flaps were raised and two test and two control implants were installed (3i TG Osseotite 3.75 x 10 and 2.8 mm transmucosal collar). The test implants were coated with a purified porcine type I collagen. Cover screws were placed and flaps were sutured. The sutures were removed 2 weeks later and a plaque-control programme was initiated. Another 2 weeks later, the procedure was repeated in the contra-lateral mandibular region. Four weeks after the second implant surgery, biopsies were obtained and prepared for histological examination. RESULTS/CONCLUSION: The vertical dimensions of the epithelial and connective tissue components as well as the composition of the connective tissue portion facing the implant were similar at collagen-coated and uncoated implants after 4 and 8 weeks of healing. It is suggested that soft tissue healing to implants coated with type I collagen was similar to that at non-coated titanium implants and that no adverse reactions to the collagen-coated implants occurred.

Some local and systemic immunological features of prepubertal periodontitis.

OBJECTIVES: The aim of the present investigation was to study local (gingival) and systemic host defense characteristics in a sample of children exhibiting local prepubertal periodontitis (LPP). MATERIAL AND METHODS: 2 groups of subjects were included in the present study. One group consisted of 11 children (9.5+/-2.0 years) with signs of periodontal disease (LPP group). A 2nd group comprised 21 adults (48.1+/-5.8 years) with advanced periodontal disease: adult periodontitis (AP) group. Gingival biopsies and a sample of peripheral blood were obtained in each individual of the AP group and in 7 out of the 11 subjects in the LPP group. The biopsies were prepared for morphometrical and immunohistochemical analysis and the blood samples prepared for immunohistochemical analysis. RESULTS: The cellular infiltrates in the biopsies of the LPP group contained a larger proportion of lymphocytes and, in particular B cells, than was the case in the AP group. The TCR Valpha/Vbeta gene expression in the lesions in the AP group was dominated by Vbeta 17 and in the LPP group by Valpha2. The content in peripheral blood of various lymphocyte sub-populations and TCR Valpha/Vbeta gene expression in the 2 groups was almost similar. CONCLUSION: It is suggested that (i) the systemic host response in children with prepubertal periodontitis has many features in common with that seen in adult patients but that (II) local defense mechanisms in the periodontitis lesion of LPP differ from those in adult periodontitis.

Some effects of periodontal therapy on local and systemic immunological parameters.

The aim of the present investigation was to study the effect of nonsurgical periodontal therapy on some local (gingival) and systemic host defense characteristics in subjects with advanced periodontal disease. 16 individuals with advanced periodontal disease were recruited. Following a clinical examination, the 3 deepest interproximal sites in the upper and lower premolar- or molar segments were selected for further analysis. Samples from the subgingival microbiota were obtained from the pocket of the selected sites and were prepared for a microbiological examination. The gingival tissue at one of the selected sites was also biopsied. Each excised soft tissue specimen was snap frozen and prepared for immunohistochemical analysis. A sample of peripheral blood was obtained from each individual and prepared for immunohistochemical analysis. Following the baseline examination, all 16 patients received periodontal therapy including oral hygiene instruction and scaling and root planing. Re-examinations regarding the clinical parameters were performed, the subgingival microbiota harvested from the sampling sites and one gingival biopsy was collected at 12 months and 24 months, respectively, among the selected sites. Samples of peripheral blood were obtained from the subjects at the 24-month re-examination. It was demonstrated that non-surgical periodontal therapy effectively reduced symptoms such as gingivitis and probing pocket depth in the subject sample and improved the overall probing attachment level. The treatment applied also markedly reduced (i) the total number of micro-organisms present in selected gingival pockets as well as (ii) the relative proportions of A. actinomycetemcomitans, P. gingivalis and P. intermedia of the subgingival microbiota. The improved clinical condition was, in addition, accompanied by a substantial reduction in the size of the inflammatory lesion (P-ICT) which in the soft tissue samples harvested at baseline was found to reside lateral to the pocket epithelium. Also qualitative alterations occurred in the lesions. Hence, following therapy (i) both the density of CD19 positive cells and the proportion of CD3 positive cells expressing TCR Vbeta genes were reduced in the P-ICT. while (ii) the overall relative number of CD3 positive cells remained unchanged. In conclusion, non-surgical periodontal therapy markedly changed the size and composition of the plaque associated lesion in the gingival tissue but apparently failed to affect the relative distribution of lymphocyte subsets in peripheral blood.

The use of metronidazole and amoxicillin in the treatment of advanced periodontal disease. A prospective, controlled clinical trial.

The present clinical trial was performed to study the effect of systemic administration of metronidazole and amoxicillin as an adjunct to mechanical therapy in patients with advanced periodontal disease. 16 individuals, 10 female and 6 male, aged 35-58 years, with advanced periodontal disease were recruited. A baseline examination included assessment of clinical, radiographical, microbiological and histopathological characteristics of periodontal disease. The 16 patients were randomly distributed into 2 different samples of 8 subjects each. One sample of subjects received during the first 2 weeks of active periodontal therapy, antibiotics administered via the systemic route (metronidazole and amoxicillin). During the corresponding period, the 2nd sample of subjects received a placebo drug (placebo sample). In each of the 16 patients, 2 quadrants (1 in the maxilla and 1 in the mandible) were exposed to non-surgical subgingival scaling and root planing. The contralateral quadrants were left without subgingival instrumentation. Thus, 4 different treatment groups were formed; group 1: antibiotic therapy but no scaling, group 2: antibiotic therapy plus scaling, group 3: placebo therapy but no scaling, group 4: placebo therapy plus scaling. Re-examinations regarding the clinical parameters were performed, samples of the subgingival microbiota harvested and 1 soft tissue biopsy from 1 scaled and 1 non-scaled quadrant obtained 2 months and 12 months after the completion of active therapy. The teeth included in groups 1 and 3 were following the 12-month examination exposed to non-surgical periodontal therapy, and subsequently exited from the study. Groups 2 and 4 were also re-examined 24 months after baseline. The findings demonstrated that in patients with advanced periodontal disease, systemic administration of metronidazole plus amoxicillin resulted in (i) an improvement of the periodontal conditions, (ii) elimination/suppression of putative periodontal pathogens such as A. actinomycetemcomitans, P. gingivalis, P. intermedia and (iii) reduction of the size of the inflammatory lesion. The antibiotic regimen alone, however, was less effective than mechanical therapy with respect to reduction of BoP - positive sites, probing pocket depth reduction, probing attachment gain. The combined mechanical and systemic antibiotic therapy (group 2) was more effective than mechanical therapy alone in terms of improvement of clinical and microbiological features of periodontal disease.

Local and systemic TCR V gene expression in advanced periodontal disease.

The aim of the present investigation was to study the expression of specific alpha/beta T cell receptor (TCR) gene products in relation to some microbiological and immunological features of advanced destructive periodontitis. 21 individuals with advanced periodontal disease (diseased group) and 16 age- and sex-matched healthy subjects (healthy group) were recruited. Following a clinical examination of the diseased group, the 3 deepest interproximal sites in the upper and lower premolar- or molar segments (i.e., 12 sites in each individual) were selected for further analysis. Samples from the subgingival microbiota were obtained from the pocket of the selected sites and were prepared for a microbiological examination. The gingival tissue at one of the selected sites was also biopsied. Each excised soft tissue specimen was divided into 2 equal portions. One portion of the biopsy was prepared for histometric and morphometric analyses. The 2nd portion was snap frozen and prepared for immunohistochemical analysis. A sample of peripheral blood was obtained from each individual of the diseased and the healthy group and prepared for immunohistochemical analysis. The selected sites of the diseased group harbored varying numbers of microorganisms which have been associated with periodontal disease. The excised gingival tissue contained inflammatory lesions with substantial numbers of lymphocytes and plasma cells including T- and B-cells and a TCR V alpha/beta gene repertoire dominated by Vbeta 17. The TCR profile of the lesion, however, differed markedly from that of the circulating blood of the diseased subjects. While only minor differences were observed between the blood samples of the diseased and the healthy subjects regarding the TCR genes, CD5, HLA-DR and CD5+CD19 positive cells occurred in higher proportions in the blood samples of the subjects susceptible to periodontal disease than in healthy controls. It may be suggested that (i) TCR V alpha/Vbeta expression in peripheral blood samples of subjects with periodontal disease does not differ from that of healthy individuals, and (ii) the periodontitis lesion expresses a unique TCR repertoire in which the Vbeta 17 gene dominates.

Composition of plaque-associated lesions in the gingiva and the peri-implant mucosa in partially edentulous subjects.

The purpose of the present investigation was to study characteristics of the plaque associated lesions in the gingiva and the adjacent periimplant mucosa sampled from the same subjects. 20 partially edentulous patients (12 female and 8 male, 30-60 years of age) volunteered to participate in the study. They had all been treated for moderate to advanced periodontal disease. Edentulous regions had been restored with implants. The restorative therapy had been completed 6-24 months prior to soft tissue biopsy. Samples of gingival tissue (GM) and periimplant mucosa (PIM) from an "interproximal surface" of one tooth site and one implant site of the same jaw were harvested. One portion of the biopsy was embedded in EPON, stained in PAS and toluidine blue and used for histometric and morphometric analyses. The 2nd portion of the biopsy was snap frozen in liquid nitrogen. 15 sections, about 5 microns thick, were prepared in a cryostat and used for immune histochemical staining. The analysis of the sections included determination of the size of the lesions as well as assessments of various cells and cell markers. In all samples of both PIM and GM discrete infiltrates of inflammatory cells (ICT) were found in the connective tissue lateral to the junctional epithelium. The ICT of PIM occupied on the average 0.17 +/- 0.14 mm2 of the soft tissue, while the corresponding lesion in GM occupied an area that was 0.25 mm2 +/- 0.21 mm2 large. The density of CD19 positive cells was 7 times higher in GM than in PIM (3.7 versus 0.5) while the densities of CD3 positive cells were 7.5 (GM) and 4.7 (PM) respectively. The density of PMN elastase positive cells was about 3 times higher in GM than in PIM (3.7 versus 1.2). Care must be exercised when these differences are interpreted. It is possible that a prolonged exposure of the implant site to the oral environment may induce both qualitative and quantitative changes of the infiltrate in PIM.

Some characteristics of the ridge mucosa before and after implant installation. A prospective study in humans.

The aim of the present investigation was to study some tissue characteristics of the ridge mucosa before and after implant installation. 9 partially edentulous patients were included in the study. At the time of fixture installation, 1 recipient site in each patient was selected for soft tissue biopsy. Abutment connection and restorative therapy were performed after 3-6 months. When the implants had been in function for about 6 months, a soft tissue sample was obtained from the keratinized peri-implant mucosa at the 1 implant site from which the first biopsy was obtained. Each biopsy was divided into 1 mesial and 1 distal portion. The mesial tissue portion was fixed in a buffered fixative and embedded in EPON. Sections were produced, stained in PAS and toluidine blue and used for histometric and morphometric analyses. The distal portion of the biopsies were embedded, snap frozen in liquid nitrogen and stored in a freezer at -70 degrees C. From each tissue portion, 15 sections were prepared in a cryostat and exposed to immunohistochemical staining. A panel of monoclonal antibodies was used and the avidin-biotin method for staining was applied. The sections were examined morphometrically. Both tissues harbored a well keratinized oral epithelium and a connective tissue, the composition of which was close to identical in terms of collagen, cells and vascular structures. The peri-implant mucosa, however, also included a junctional epithelium which evidently allowed the penetration of products from the oral cavity. As a consequence, the periimplant mucosa in comparison to the masticatory mucosa was found to contain significantly enhanced numbers of different inflammatory cells.

The CYP2D6 genotype predicts the oral clearance of the neuroleptic agents perphenazine and zuclopenthixol.

BACKGROUND: Most antidepressant and neuroleptic agents are metabolized by the polymorphic cytochrome P450 enzyme CYP2D6. This study evaluates the importance of the CYP2D6 genotype for the disposition of the neuroleptic agents perphenazine and zuclopenthixol. METHODS: Patients treated with neuroleptic agents (n = 36) were studied prospectively with regard to CYP2D6 genotype and neuroleptic plasma concentration during oral treatment. Because no patient provided enough samples for individual kinetic modeling, a bayesian approach was used for determination of the clearance. Population kinetic parameters for this procedure were collected from retrospective therapeutic drug monitoring data (n = 113) by use of a nonparametric approach. RESULTS: The CYP2D6 genotype significantly predicted the oral clearance of perphenazine and zuclopenthixol (p < 0.01 by multiple regression). The difference in clearance between homozygous extensive metabolizers and poor metabolizers was threefold for perphenazine and twofold for zuclopenthixol. CONCLUSION: The results show that the genotype for CYP2D6 is closely related to the oral clearances of perphenazine and zuclopenthixol. If this finding can be confirmed in a larger population, genotyping may become an important tool for the dosing of these two neuroleptic agents.

Two-year outcome of team-based intensive case management for patients with schizophrenia.

OBJECTIVES: Two-year outcomes of patients with schizophrenic disorders who were assigned to an intensive, team-based case management program and patients who received standard psychiatric services were assessed. The case management model featured increased staff contact time with patients, rehabilitation plans based on patients' expressed needs, and patients' attendance at team meetings where their rehabilitation plan was discussed. METHODS: Forty patients were randomly assigned to either the case management group or the control group that received standard services. Patients' use of emergency and inpatient services, their quality of life, the size of their social networks, and their relatives' burden of care were assessed at assignment to the study groups and at two-year follow-up. RESULTS: Patients in the case management group had significantly fewer emergency visits compared with the two years before the study, and their relatives reported significantly reduced burden of care associated with relationships with psychiatric services over the two-year period. The size of patients' social networks increased for the case management group and decreased for the control group. CONCLUSIONS: A team-based intensive case management model is an effective intervention in the rehabilitation of patients with chronic schizophrenia.

Some microbiological, histopathological and immunohistochemical characteristics of progressive periodontal disease.

The aim of the present investigation was to study the local nature of human periodontal disease by assessing the microbiota and the composition of the tissue lesions at sites with progressive attachment loss in periodontitis susceptible subjects. 300 subjects with periodontal disease were monitored for 2 years without treatment. 8 subjects lost > 2 mm of attachment at > or = 3 sites during both the first and the second 12 month interval. These 8 subjects (progressive disease group; PD) were recalled for a microbiological and histopathological examination. A group of age- and sex-matched subjects were identified who during the 2 years of monitoring exhibited gingivitis and deep pockets, but no further attachment loss. This group of 11 subjects (non-progressive disease group; NPD) served as controls. From the 8 active disease subjects, > or = 1 interproximal site which had displayed disease activity (progressive disease active; PDA) and > or = 1 contralateral site without disease progression (progressive disease inactive; PDI) were sampled. From the 11 control subjects, 1 site/subject was sampled (NPD). The total number of viable micro-organisms (TVC) in the subgingival microbiota was estimated and a series of bacterial species were identified and enumerated. The gingival tissue of the sampling site was excised and the soft tissue prepared for morphometrical and immunohistochemical analyses. No differences were observed in the subgingival microbiota of the sample sites in the subjects who exhibited disease progression (PD) when compared with the subjects with periodontally diseased but stable conditions (NPD).(ABSTRACT TRUNCATED AT 250 WORDS)

Long-standing plaque and gingivitis at implants and teeth in the dog.

The experiment was performed to evaluate the effects of long-standing plaque on the gingiva and peri-implant mucosa. 5 beagle dogs were used in the study. The mandibular right premolars were extracted. 3 months later, 3 titanium fixtures were installed and after another 3 months, abutment connection was performed. Plaque control, in the implant as well as the contralateral tooth regions, was maintained during a 4-month period prior to the start of the main experiment. On Day 0, the teeth and implant sections were examined with respect to plaque and gingivitis. The plaque control program was terminated. The animals were subsequently fed a diet which allowed gross plaque accumulation. After 90 days of undisturbed plaque formation, the dogs were re-examined and biopsies harvested from implants and contralateral teeth. On day 90, all teeth and implants had accumulated large amounts of plaque. The soft tissue at implants and teeth bled on gentle probing. The histological examination of the gingiva and the peri-implant mucosa revealed: (i) both tissues contained an inflammatory cell infiltrate; ICT, (ii) the apical extension of ICT was more pronounced in the peri-implant mucosa than in the gingiva and (iii) the composition of the 2 lesions had many features in common.

Soft tissue reaction to de novo plaque formation on implants and teeth. An experimental study in the dog.

The aim of the present investigation was to assess the effect of de novo plaque formation on the gingiva and masticatory mucosa around teeth and implants. The study was performed in 5 beagle dogs which at the initiation of the experiment were 15 months old. During a preparatory period, the mandibular right premolars were extracted, 3 fixtures installed, abutment connection performed and a 4-month period of plaque control completed. A clinical examination was performed and biopsies of the second mandibular premolar (P2) and the contralateral implant site (2P) were sampled. The dogs were allowed to form plaque during a period of 3 weeks. The clinical examination was repeated and biopsies harvested from the 2 remaining implants and the contralateral tooth sites. The tissue samples were prepared for histometric and morphometric analysis. Both the masticatory mucosa at implants and the gingiva responded to de novo plaque formation with the development of an inflammatory lesion. The size as well as the composition of the lesions in the 2 tissues had many features in common. It was concluded that the mucosa around implants and the gingiva around teeth had a similar potential to respond to early plaque formation.

Experimental breakdown of peri-implant and periodontal tissues. A study in the beagle dog.

The objective of the present experiment was to study lesions in the peri-implant and periodontal tissues resulting from ligature placement and subgingival plaque formation. The experiment was performed in 5 beagle dogs which at the start of the study were about 15 months old. They were given a diet which allowed gross plaque formation. The mandibular right premolars were extracted, 3 fixtures (a.m. Brånemark) installed and abutment connection performed. Towards the end of a 6-month plaque control period, a clinical and radiographic examination was performed. Ligatures were placed in a subgingival position at 2 of the implants and the contralateral premolars. Plaque was allowed to accumulate. After 6 weeks, the ligatures were removed. 1 month later, the clinical and radiographical examination was repeated and samples from the subgingival microbiota obtained. Biopsies from the teeth and implant sites were harvested and processed for histometric and morphometric analyses. The results from the clinical and histological examinations revealed that: (i) clinical and radiographic signs of tissue destruction were more pronounced at implants than at teeth; (ii) the size of the soft tissue lesion was larger at implants than at teeth; (iii) the lesion at implants but not at teeth extended into the bone marrow.

Enhanced gingivitis in the deciduous and permanent dentition. An experimental study in the dog.

The aim of the experiment was to analyze the reaction of the marginal gingival tissues to 21 days of plaque formation on buccal tooth surfaces in the deciduous and permanent dentition of beagle dogs. In order to enhance the formation of plaque, the buccal surfaces of the experimental teeth were coated with a composite filling material. 5 beagle dogs were used. The animals were monitored during 2 periods, called period A (42 days during the deciduous dentition) and period B (42 days during the permanent dentition). The dogs were 10 weeks old at the initiation of period A. Following 3 weeks of plaque control, a groove was prepared into the enamel of the buccal surfaces of the mandibular right 3rd (03P) and 2nd (02P) premolars. A cotton ligature was subsequently attached to the groove using an enamel/etch-technique and a composite filling material. The groove and the ligature did not interfere with the gingival margin but the composite material extended into the subgingival niche. The plaque control measures were abandoned. The animals formed plaque during the following 21 days. A clinical examination was performed and subgingival bacteria sampled on day 21. Moreover, biopsies were harvested from the 03P and 02P tooth regions. The biopsies were prepared for histometric and morphometric analyses. A 2nd plaque control regimen was initiated. Period B started when the dogs were 15 months old. Following 3 weeks of enhanced plaque control, a cotton ligature was attached as described above at the buccal surfaces of the mandibular left 3rd (P3) and 4th (P4) premolars.(ABSTRACT TRUNCATED AT 250 WORDS)

Periodontal tissue reactions to orthodontic extrusion. An experimental study in the dog.

Orthodontic tooth extrusion is used at crown lengthening procedures or in conjunction with periodontal therapy aimed at eliminating or reducing angular bone defects. A technique for orthodontic extrusion combined with resection of the supracrestal attachment fibers (fiberotomy) was recently proposed as an adjunct to certain restorative procedures. The aim of the present investigation was to analyze reactions of the periodontal tissues to orthodontic extrusion when combined with fiberotomy. In 5 beagle dogs, the mesial roots of the 2nd, 3rd and 4th hemisected mandibular premolar were used as target roots while the distal roots served as reference units. After a baseline examination, an orthodontic extrusion device (stent) was installed and reactivated at 2-week intervals during an 8-week period of active tooth movement. Immediately following the installation of the stent and once every 2nd week, the target roots were exposed to fiberotomy. After the active period, the teeth were retained in their new position for a period of 8 weeks. Clinical, radiographical and histological measurements were performed. The results from the investigation demonstrated that orthodontic extrusion combined with supracrestal fiberotomy resulted in a coronal displacement of the tooth and was associated with pronounced recession of the gingival margin and extensive loss of connective tissue attachment. The degree of gingival recession and the amount of loss of connective tissue attachment were, however, less extensive than the amount of tooth extrusion. Thus, repeated fiberotomy obviously failed to entirely prevent coronal migration of the attachment apparatus. It was also observed that undesired attachment loss had occurred at the reference roots.

The soft tissue barrier at implants and teeth.

In the present animal experiment, analyses and comparisons were made between the structure and composition of clinically healthy supraalveolar soft tissues adjacent to implants and teeth. 5 beagle dogs were used. The right mandibular premolar region was selected in each dog for placement of titanium implants, while the left mandibular premolar region served as control. Extractions of the mandibular premolars were preformed, healing allowed, following which titanium fixtures were installed in the edentolous premolar region. Abutment connection was carried out 3 months later. After another 2 months of healing, plaque control was initiated and maintained for 8 weeks. At the end of the plaque control period, clinical examinations were performed and biopsies harvested from the implant site and the contralateral premolar tooth region. Following fixation and decalcification, all tissue samples were embedded in EPON and examined by histometric and morphometric means. The result from the analyses demonstrated that the periimplant mucosa which formed at titanium implants following abutment connection had many features in common with gingival tissue at teeth. Thus, like the gingiva, the peri-implant mucosa established a cuff-like barrier which adhered to the surface of the titanium abutment. Further, both the gingiva and the peri-implant mucosa had a well-keratinized oral epithelium which was continuous with a junctional epithelium that faced the enamel or the titanium surface. In the periimplant mucosa, the collagen fibers appeared to commence at the marginal bone and were parallel with the abutment surface. All gingival and periimplant units examined were free from infiltrates of inflammatory cells. It was suggested that under the conditions of study, both types of soft tissues, gingiva and periimplant mucosa, have a proper potential to prevent subgingival plaque formation.

Gingivitis in the deciduous and permanent dentition. An experimental study in the dog.

The present investigation was performed in order to study the reaction of the gingiva in the deciduous and permanent dentition of dogs to 3 weeks of plaque accumulation. The study was carried out in 10 beagles, divided into 2 groups of 5 dogs each; group I and group II. When the dogs of group I were 10 weeks old, a meticulous plaque control regimen was initiated in order to establish clinically healthy gingiva. After 6 weeks of plaque control, the gingivae of the lower deciduous molars was exposed to a clinical examination, and biopsies as well as bacterial plaque samples were harvested from tooth 03P and 02P. A second plaque control regimen was initiated when the same dogs were 15 months old. After 6 weeks of plaque control, the gingiva of the permanent dentition was examined and biopsies sampled from tooth P3 and P4. In the dogs of group II, plaque control regimens of 3 weeks duration were initiated when the animals were 10 weeks and 15 months old. Clinical examinations were performed at the end of each 3-week period. Immediately after the clinical examinations. 3-week periods of plaque accumulation were initiated. Examinations and plaque sampling were performed after each of these 3-week periods and biopsies were sampled from the deciduous and permanent dentition as described for group I. The biopsies were processed for histometric and morphometric measurements. The findings from the experiment showed that careful plaque control resulted in the establishment of clinically healthy gingiva. In both the deciduous and permanent dentition, however, a clinically healthy gingiva was found to contain a small inflammatory cell infiltrate (ICT). 3 weeks of plaque accumulation resulted in both dentitions in the development of clinical signs of gingivitis and in the formation of comparatively large ICT. The large ICT of the permanent gingiva resided in the coronal portion of the free gingival unit, while in the deciduous dentition, the inflammatory lesion occupied a narrow tissue portion along the entire border of the dento-gingival epithelium. The ICT of the permanent gingiva harbored a larger portion of plasma cells than the inflammatory lesion studied in the deciduous dentition.

The prevalence of insomnia: the importance of operationally defined criteria.

Previous studies on the prevalence of sleep disturbances have shown that insomnia occurs in 3.2-42% of different populations. The wide reported variation in prevalence prompted a rigorous definition of insomnia to be introduced in this study. Randomly selected members of the population aged 30 to 65 years from two geographically different rural parts of central Sweden answered a sleep questionnaire. The response rates were 69.2% and 70.2%, respectively. Females significantly more often reported difficulty in falling asleep (7.1% of the women and 5.1% of the men). Among women 8.9 and among men 7.7% of individuals reported trouble with nocturnal awakenings. Using a stringently defined concept of insomnia as a disorder of initiating sleep (DIS), the prevalence rate of insomnia among women was 1.1% and among men 0.5%. Defining insomnia as a disorder of maintaining sleep (DMS), the prevalence among both women and men was 1.1%. Defining insomnia as a disorder of initiating and maintaining sleep (DIMS), the prevalence rate was 1.7% among women and 1.4% among men. This prevalence, which is lower than previously reported, demonstrate the importance of an operational definition of insomnia.