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The aim of the present study was to analyze some features of the peri-implant mucosa at sites in the dog model which had been exposed to plaque accumulation for periods up to 9 months. The experiment was carried out in 5 labrador dogs. The mandibular right and left 2nd, 3rd and 4th premolars (2P2, 3P3, 4P4) and the 1st molars (1M1) were extracted. Following a 3-month healing period, 3 titanium fixtures (Nobelpharma AB, Göteborg, Sweden) were installed in the edentulous premolar/molar regions. Abutment connection was performed 3 months later and a meticulous plaque control period of 3 months was initiated. A clinical examination was performed at the end of this preparatory period and a main study period of 9 months continued. During this period, the plaque control regimen was maintained in the mesial and central (left: L1, 2 and right: R1, 2) implant segments, whereas plaque was allowed to accumulate on the distal implants, i.e.. L3 and R3. At the end of the main study period, i.e., 12 months after abutment connection, the clinical examination was repeated, the animals perfused and biopsies obtained. Semi-thin sections were produced for histometric and morphometric analyses. The peri-implant mucosa at implant sites exposed to daily and comprehensive plaque control at biopsy was clinically noninflamed and the connective tissue lateral to a junctional epithelium was devoid of accumulations of inflammatory cells.(ABSTRACT TRUNCATED AT 250 WORDS)

The present experiment in the Labrador dog was performed to study tissue alterations that occurred in a peri-implantitis lesion following ligature removal. The study was carried out in 5, 1-year old Labrador dogs. The mandibular right and left 1st molars and 4th and 3rd premolars were extracted to establish recipient sites for implants. After 3 months of healing, 4 titanium fixtures, 2 in each jaw quadrant, were installed and abutment connection carried out in a 2nd stage procedure after another 3 months. After a 6-month period of healing, cotton floss ligatures were placed in a submarginal position around the neck of the fixture abutments. The ligatures were forced into a position "apical" of the margin of the peri-implant mucosa and secured. When the tissue destruction after 4-6 weeks was found to amount to about 25% of the original bone height at each individual implant, the ligatures were removed. 2 dogs were sacrificed 1 month and 3 dogs 3 months after ligature removal. The animals were perfused with a fixative and block biopsies were obtained from the implant sites. The biopsies were prepared for histometric and morphometric analyses.(ABSTRACT TRUNCATED AT 250 WORDS)

The purpose of the present study was to examine the relationship between the form of the crowns in the maxillary front tooth segment and (1) a group of morphological characteristics and (2) the thickness of the gingiva. 108 subjects devoid of symptoms of destructive periodontal disease were examined regarding, e.g., probing depth, thickness of the free gingiva, width of the keratinized gingiva and the contour of the marginal gingiva. From clinical photographs of the maxillary front tooth region, the width (at the apical third – CW) and the length (CL) of the crowns of the 6 front teeth were determined. A CW/ CL-ratio was calculated for each tooth and averaged for each tooth region. The individual mean CW/CL-ratio values for the central incisors were ranked. After correction for incisal attrition, the 10 subjects ranked highest and the 10 ranked lowest were selected as having either a long-narrow (group N) or a short-wide (group W) form of the crown of the tooth. The data for each of the examined parameters were averaged for each tooth region in each subject and mean values for subjects in groups W and N were compared using the Student t-test. Stepwise multiple regression analysis, including data from the whole sample, was performed for each tooth region with the thickness of the free gingiva as the dependent variable. The results from the analyses demonstrated that individuals with a long-narrow form of the central incisors displayed, compared to individuals with a short-wide crown, form (i) a narrow zone of keratinized gingiva, (ii) shallow probing depth, and (hi) a pronounced “scalloped” contour of the gingival margin. There was no significant difference between groups N and W with respect to the thickness of the free gingiva. The CW/CL-ratio data revealed that a certain form of the crowns in the central incisors was accompanied by a similar form in the lateral incisor and canine tooth region. The regression analyses demonstrated that the thickness of the free gingiva in central incisors was significantly related to (i) the width of the keratinized gingiva, (ii) the buccolingual width of the crown and (iii) the presence of an interproximal gingival groove. In lateral incisors, the thickness of the free gingiva was associated with the probing depth at the buccal surface. No single variable was significantly related to the thickness of the gingiva in canines.

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.

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. Branemark) 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.

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.

The purpose of this study was to analyze the expression of adhesion molecules on endothelial cells in the alveolar ridge mucosa, the gingiva and the periimplant mucosa in humans.Twelve partially edentulous subjects were included in the study. In each subject, one soft tissue biopsy was harvested from the edentulous alveolar ridge mucosa, one from a tooth site and one from an implant site. After 3 weeks of undisturbed plaque accumulation, an additional biopsy was obtained from one tooth and one implant site in each subject. The tissue samples were snap frozen and prepared for immunohistochemical analysis.In the alveolar ridge mucosa, smaller proportions of endothelial cells expressing ICAM-1, ELAM-1 and VCAM-1 were observed than in the gingiva. ELAM-1-positive cells occurred in lower numbers than in periimplant mucosa. After 21 days of plaque accumulation, ELAM-1 was increased in tooth sites, but decreased in periimplant mucosa.The results of the present study indicated that the proportions of activated endothelial cells and the extravasation of leukocytes is larger in gingiva and periimplant mucosa than in alveolar ridge mucosa. This might be due to the less permeable keratinized epithelial layer in the edentulous ridge mucosa, which offers proper protection against microbial pathogens. The greater expression of endothelial cell adhesion molecules during experimental gingivitis, compared to periimplant mucositis, may reflect its longer history of repeated antigenic assaults.

The aim of this study is to report about the dental health situation in Switzerland and to evaluate frequencies of dental visits. Data were obtained from the first and second national Health Survey of the Federal Office for Statistics in 1992/3 and 1997. Based on a random sample of the population aged from 15 to 74 years, 71% participated in an oral interviews and of this group of individuals, 75% later filled in a written questionnaire in 1992/3. Data analysis showed that the proportion of the fully dentate population (28 remaining teeth) is 41%, while almost 50% had some prosthetic treatment. 31% were treated with fixed prostheses, i.e.crowns and/or bridges, and 19% with removable prostheses, i.e. partial and/or full dentures. With increasing age the number of missing teeth and the frequency of prosthetic treatment went up. The population with prosthodontic reconstruction increased mainly in the third and forth decades. In the elderly population (age 65-74 years), a shift was observed from fixed to removable prostheses; two thirds in this groups was restored with removable prostheses. The proportion of subjects visiting the dentist was by 70% in 1992/3 and declined to 65% in 1997. Subjects wearing removable prostheses had apparently lower frequencies (43%) in dental visits than subjects with fixed prostheses (80%). A potential concern exists for the edentulous population who presented a limited need for dental visits of only 22% during the year preceding the study.

The aim of the present study was to investigate the healing of alveolar ridge defects augmented with cancellous bovine bone mineral. In six partially edentulous patients, bone augmentation was necessary prior to implant placement because of severe alveolar ridge resorption. The defect sites, all located in the maxilla, were filled with Bio-Oss and covered with the resorbable collagen membrane Bio-Gide. Biopsies were obtained from the defect sites 6 to 7 months following grafting and were processed for ground sectioning. The histologic analysis revealed that the Bio-Oss particles occupied 31% of the total biopsy area. An intimate contact between woven bone and Bio-Oss was detected along 37% of the particle surfaces. A mixed type of bone was found; it contained woven bone and parallel-fibered bone, which demonstrates features of remodeling activity. Signs of resorption of the grafting material were observed in the histologic sections, which indicates that the material takes part in the remodeling process. It is suggested that Bio-Oss may be a very suitable material for staged localized ridge augmentation in humans.

The aim of this prospective 5-year longitudinal study was to follow endosteal implants in which guided bone regeneration (GBR) was applied during implant placement. In 75 patients, defects around implants (Branemark System) were treated with Bio-Oss and Bio-Gide (112 implants). In split-mouth patients in this group, Bio-Oss and Gore-Tex were used in the second defect site (41 implants). All 75 patients had at least 1 implant that was entirely surrounded by bone and served as the control (112 implants). After placement of the definitive prostheses (single-tooth, fixed, or removable implant prostheses), patients were recalled after 6 months and then every 12 months during a 5-year observation period. The following variables were investigated: implant survival, marginal bone level (MBL), presence of plaque, peri-implant mucosal conditions, height of keratinized mucosa (KM), and marginal soft tissue level (MSTL). The cumulative implant survival rate after 5 years varied between 93% and 97% for implants treated with or without GBR. The mean MBL after 60 months was 1.83 mm for sites treated with Bio-Oss and Bio-Gide, 2.21 mm for sites treated with Bio-Oss and Gore-Tex, and 1.73 mm for the control sites. The MBL values were found to increase significantly with time and differed significantly among the treatment groups. During the observation period, KM varied between 3.16 and 3.02 mm. A slight recession of 0.1 mm was observed, and plaque was found in 15% of all sites and was associated with inflammatory symptoms of the peri-implant mucosa. It was observed that such symptoms and recession correlated more strongly with the type of restoration than with the type of treatment. This study demonstrated that implants placed with or without GBR techniques had similar survival rates after 5 years, but that bone resorption was more pronounced in sites with GBR treatment. It was assumed that the use of GBR is indeed indicated when the initial defect size is larger than 2 mm in the vertical dimension.

The purpose of this study was to examine reactions of gingiva and peri-implant mucosa (PiM) to de novo plaque accumulation in humans.Prior to the start of the study, which included 12 partially edentulous subjects, a 3-week plaque control program was performed. Ethical approval was granted by the local ethics committee. On day 0, 2 soft tissue biopsies were harvested, 1 from a tooth and 1 from an implant site in every subject. After 3 weeks of undisturbed plaque accumulation (day 21), 2 additional biopsies were obtained from the gingiva and PiM in each subject. The tissue samples, each 4x4 mm in size, were snap frozen and prepared for immunohistochemical analysis.The size of the infiltrate (ICT) in the day 0 biopsies, was about 0.03 mm2 in both the gingiva and PiM. At the end of the plaque accumulation period, the size of the lesion had significantly increased in both groups and occupied an area of 0.26 mm2 in the gingiva and 0.14 mm2 in PiM. In the biopsies presenting day 0, the proportions of the various cell populations examined were similar in the gingiva and in PiM. The tissue fractions of almost all types of cells increased during the 3 weeks, but the mean change for each cell type was greater in the gingiva than in PiM. The CD3/CD19 ratio decreased in the gingiva between day 0 and 21, but increased in PiM.The results of the present study indicated that plaque accumulation induced an inflammatory response characterized by increased proportions of T- and B-cells in the ICT of both the gingiva and the PiM. Although not statistically significant, the host response in the gingiva tended to be more pronounced than in the peri-implant mucosa.

The purpose of this article is to draw attention to the possible complications of foreign body ingestion or aspiration associated with dental treatment, especially oral implant treatment. A guide for the management of swallowed or inhaled objects is given. When the object cannot be coughed out, then it is mandatory to take frontal and lateral chest roentgenograms to identify the object's position in the intestinal system or in the tracheobronchial tree. In case of ingestion, attempts should be made to recover the foreign object by esophagoscopy. Aspirated foreign bodies should be removed within 24 hours. Acute obstruction can be life threatening and delaying the removal of foreign objects may make a bronchoscopy technically more difficult. The clinician must be aware of the complications involved in accidentally inhaling or ingesting foreign bodies during dental treatment. Patients at greater risk of swallowing or aspirating foreign objects need to be identified and extra preventive steps must be taken to avoid such complications.

The aim of this article is to describe the indication criteria and the treatment planning for a maxillary implant-supported removable overdenture. Prostheses are designed according to the requirements of the bar system and the factors influencing the extension of the prosthesis base.The decisive factors in determining whether a bar-retained overdenture prosthesis is indicated should be evaluated during the initial clinical examination and with the help of a reformatted computed tomographic (CT) scan that is performed with a radiologic template in place. Titanium markers represent the ideal location of the denture teeth in the diagnostic setup so that the implant position can be selected and the available space for the bar system can be assessed vertically and horizontally.For the overdenture prosthesis that is solely implant supported 6 to 8 implants are placed ideally at a distance of about 10 to 14 mm from center to center. A prefabricated bar system that allows the clips to be inserted between the implants can then be used. When the available bone restricts implant placement to adjacent tooth positions an individually milled bar that includes additional frictional pins and/or retentive elements needs to be planned. The prosthesis design, in particular its buccal and palatal flange extension, is determined during setup try-in, taking into account the patient's smile line, their need for facial support, and their phonetic requirements.The removable implant-supported overdenture offers flexibility in placing implants in either adjacent tooth positions or with greater distances between them depending on the available bone, as either conventional bar and clip systems or individually milled bars can be used. Adjustment of the buccal prosthesis flange and the palatal prosthesis base is made to fulfill the patient's requirements concerning esthetics, phonetics, comfort, and function.

The aim of the present article was to describe the treatment planning for an implant-supported maxillary fixed prosthesis and the clinical procedure involved, including the laboratory fabrication sequence.If patients request a fixed prosthesis to restore the edentulous maxilla, it is essential to decide as soon as possible whether this prosthesis design can satisfy the requirements of esthetics, phonetics, comfort, and function. Thus, the crucial clinical factors need to be checked during examination. Furthermore, the relationships between ideal implant angulation, available bone, and intended crown should be assessed using reformatted computed tomography.In patients with minimal bone resorption and limited intermaxillary space, implants can usually be placed in the prosthetically driven implant position for a fixed prosthesis. To evaluate and optimize esthetics, biology, and function, a fixed provisional restoration should be inserted for a 6-month diagnostic period. The ideal provisional then serves as a guide for the final restoration.If clinical and radiologic diagnostics indicate that an implant-supported fixed complete denture is feasible, meticulous presurgical planning, precise execution of implant positioning, and a progressive prosthetic treatment sequence are required. The ceramometal fixed implant-supported restoration can then be established in an ideally prepared and matured oral environment.

The aim of this article was to present the CAD/CAM-assisted Procera system as a new all-ceramic full-coverage crown system. New technologies need to be evaluated technically and clinically to be able to fulfill the requests for aesthetics, physical strength and biocompatibility when restoring the anterior and posterior region. The Procera AllCeram system offers the opportunity to fabricate densely sintered, high-purity, tooth-colored copings. Mechanical properties of the Procera alumina coping, indications and contraindications and additional applications are discussed. The clinical and technical procedures and any specific limitations and peculiarities are summarized and documented with clinical cases in a step-by-step illustration.

The purpose of this study was the clinical and microbiological re-examination of dental hygienists, who, 30 months before, had shown remarkably high supragingival levels of periodontitis-associated micro-organisms. Interdental plaque was collected from the same molar sites and investigated by the same immunofluorescence assay with taxa-specific monoclonal antibodies as at the initial examination. On average, the 15 re-examined subjects showed slightly increased plaque levels but unchanged bleeding on probing scores (0.3-1.4). Pocket formation was restricted to a single subject. Prevotella intermedia/P. nigrescens and Peptostreptococcus micros were present in every plaque sample. Prevalences of Actinobacillus actinomycetemcomitans, Bacteroides forsythus and Campylobacter rectus were again between 20-40%, but some fluctuation within subjects was noted. The data confirm supragingival plaque as a natural habitat for periodontitis-associated bacteria in periodontially healthy persons, and indicate that colonization with A. actinomycetemcomitans, B. forsythus or C. rectus is mostly stable in spite of better than average personal plaque control.

The increasing use of oral endoprostheses has offered new alternatives for fixed and removable prosthesis design. However, the use of implants also requires the complex understanding and use of sound prosthodontic principles. The establishment of proper maxillomandibular relationships (vertical dimension, occlusal plane, curve of Spee, tooth arrangement), esthetics, and function are essential precursors to success. Although the usefulness of rehabilitation with overdentures supported by osseointegrated fixtures is sometimes underestimated, overdentures provide an adequate treatment alternative in indicated cases. A case is presented in which previous preprosthetic surgery had failed and subsequently an overdenture supported by osseointegrated fixtures was constructed.

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.

In a combined retrospective longitudinal study an evaluation of different dental and periodontal indexes (tooth mobility, probing pocket depth, plaque index, sulcus bleeding index, probing attachment level) in 62 patients with 77 resin-bonded bridges was performed. The direct comparison between test (abutment) and control (non-abutment) teeth revealed no differences at the day of evaluation in comparison to the date of incorporation. The longitudinal evaluation resulted in more favourable values at the day of evaluation in comparison to the date of incorporation for both the test and control teeth. Despite the altered contour of the abutment teeth, resin-bonded bridges seem not to change the periodontal status in a long-term evaluation, if good patient cooperation and regular care by a dental hygienist are guaranteed.

788 patients with 3-unit resin-bonded bridges were followed up over a time period of up to 5 years after placement. In this multicenter study, the following clinical variables were analyzed: caries, periodontal disease, loss of pulp vitality and the behavior of the dental materials involved were assessed. Adverse findings were rare. More data are needed over a longer period of time to support the present results.

An evaluation of about 300 abutment teeth of resin-bonded bridges (Rochette, electrochemically etched) and resin-bonded extracoronal attachments was performed to determine the surface area and the length of the circumference of the retainers. By using a combined indirect (preparation of the specimen) and direct (automatic image analysis) method for the determination of both parameters a mean value of 50 mm2 for the surface area and 30 mm for the circumference, respectively, was evaluated. In addition, two indices (loading-index (BI): sigma surface area/width of pontic tooth; moisture penetration-index (FPI): sigma surface area/sigma circumferences) as predictors for the longevity of resin-bonded reconstructions were calculated. The loading-index was a good predictor for successful reconstructions: the clinical success was the better, the bigger the retention area, and the smaller the circumference of the retainer and the smaller the pontic tooth.

The surface area and the longest diameter of gingival and palatal corneocytes and of superficial alveolar mucosa cells were assessed morphometrically. From a total of 92 subjects (46 males, 46 females) 5 to 75 years of age, cells of each class were collected by either the strip method or the imprint technique. The nuclear and cytoplasmic profiles and the diameter of about 30 cells per class and subject were drawn and scanned with a MOP-I system (Kontron, Zürich). Average data collected for 8 groups of males and females of increasing age demonstrated that with respect to the two parameters neither corneocytes nor exfoliating alveolar mucosa cells changed in size with increasing age, ther was no general difference in cell size between the sexes, and gingival corneocytes with retained nuclei were slightly larger than those without nuclei, particularly in males. These observations are in contrast to those reported for epidermal corneocytes.

The purpose of this research was to analyze simultaneously the effect of 4 factors (metal conditioning, bonding agent, metal silicoating and water storage) on the tensile behavior of a Bis-GMA-resin (hybridfilled) bonded Ni-Cr-Be alloy by analysis of variance with a multifactorial design. The results showed that water storage of 33 days and the presence of bonding agent had no effect. In contrary, electrolytical etching or silicoating influenced significantly and positively the tensile bond strength. In addition a significant factors interaction between metal surface conditioning (sandblasting vs. etching) and silicoating was detected. Metal sandblasting followed by silicoating reacted more favorably than the combination etching/silicoating. In all cases the mechano-chemical adhesion (silicoating technique) resulted in a composite bond strength that was far superior to that of conventional pure mechanical bonding.