Motor skills and school performance in children with daily physical education in school--a 9-year intervention study.

The aim was to study long-term effects on motor skills and school performance of increased physical education (PE). All pupils born 1990-1992 from one school were included in a longitudinal study over nine years. An intervention group (n = 129) achieved daily PE (5 × 45 min/week) and if needed one extra lesson of adapted motor training. The control group (n = 91) had PE two lessons/week. Motor skills were evaluated by the Motor Skills Development as Ground for Learning observation checklist and school achievements by marks in Swedish, English, Mathematics, and PE and proportion of pupils who qualified for upper secondary school. In school year 9 there were motor skills deficits in 7% of pupils in the intervention group compared to 47% in the control group (P < 0.001), 96% of the pupils in the intervention group compared to 89% in the control group (P < 0.05) qualified for upper secondary school. The sum of evaluated marks was higher among boys in the intervention group than in the control group (P < 0.05). The sum of marks was also higher in pupils with no motor skills deficit than among pupils with motor skills deficits (P < 0.01), as was the proportion of pupils who qualified for upper secondary school (97% vs 81%, P < 0.001). Daily PE and adapted motor skills training during the compulsory school years is a feasible way to improve not only motor skills but also school performance and the proportion of pupils who qualify for upper secondary school.

ADHD symptoms and maturity--a study in primary school children.

AIM: To study if age and non-behavioural measures of biological maturity have any associations with attention deficit hyperactivity disorder (ADHD). METHODS: Two hundred fifty-one children 7 to 9 years of age in a Swedish school were screened for ADHD-symptom. ADHD-symptoms were estimated by Conners Abbreviated Questionnaire by both parents and teachers. Motor function, body weight and body height were measured. Skeletal age was estimated through hand radiographs. RESULTS: Height, weight and skeletal bone-age did correlate significantly with age (rs = 0.44-0.69, p < 0.001) but not with ADHD symptom scores. Motor dysfunction had a weak negative correlation with age (rs =-0.21, p < 0.05). Parent and teacher scores of ADHD-symptoms did not correlate with age. CONCLUSION: This study showed that the variables measuring general biological maturity had a strong association with age, whereas motor dysfunction and ADHD symptoms had no significant association with age. ADHD symptoms did not correlate with the variables measuring general biological maturity. These results do not support the hypothesis that a general biological immaturity is an important etiologic factor for ADHD symptomatology.

Spontaneous progression of experimentally induced periimplantitis.

BACKGROUND: Periimplantitis represents an inflammatory condition that is associated with the presence of a submarginal biofilm and with advanced breakdown of soft and mineralized tissues surrounding endosseous implants. Animal models have been used to describe mechanisms involved in the pathogenesis and treatment of the soft and hard tissue lesions of periimplantitis. OBJECTIVE: The aim of the present experiment was to study the presence and progression of inflammatory lesions in tissues surrounding implants exposed to "experimental periimplantitis". MATERIAL AND METHODS: Five Labrador dogs were used. In each dog, 2 or 3 implants were placed in both the left and right edentulous premolar regions of the mandible. Abutment connection was performed 4 months later and a plaque control regimen was initiated and maintained for 5 months. "Experimental periimplantitis" was subsequently induced by ligature placement and plaque accumulation was allowed to progress until about 40% of the height of the supporting bone had been lost. The ligatures were removed, but plaque formation was allowed to continue for an additional 12 months. Radiographs of all implant sites were obtained before and after active "experimental periimplantitis" as well as at the end of the experiment. Biopsies were harvested from the implant sites in 3 of the dogs. The tissue samples were prepared for light microscopy and the sections were used for histometric and morphometric examinations. RESULTS: One implant was lost during the first 2 months of "experimental periimplantitis" and two implants were lost during the 12 months that followed ligature removal. The radiographic examination indicated that varying amounts of additional bone loss occurred in the majority of the implant sites also following ligature removal. The mucosa of all implant sites harbored inflammatory lesions that extended apically of the pocket epithelium. The lesions were separated from the marginal bone by a zone of apparently normal connective tissue. CONCLUSION: A remission of the destructive inflammatory lesion in the periimplant tissues was seen in some sites following ligature removal, but in the majority of sites additional loss of supporting bone occurred.

Prospective 3-year study of cross-arch fixed partial dentures in patients with advanced periodontal disease.

STATEMENT OF PROBLEM: Several choices exist for the treatment of advanced periodontal disease. One is a combined periodontal and prosthetic treatment that includes cross-arch fixed partial dentures (FPDs). However, the outcomes of such therapy have been reported mainly from studies in Scandinavian countries. PURPOSE: The aims of this study were: (1) to longitudinally evaluate, after periodontal and prosthodontic treatment that included cross-arch FPDs, treatment outcomes in Korean patients who suffered from severe periodontitis; and (2) to evaluate the patients' treatment assessments and the FPDs after 3 years. MATERIAL AND METHODS: This survey included 39 Korean patients provided with 50 FPDs. Clinical and radiographic examinations were performed at the time of delivery of the FPDs and at the 3-year follow-up examinations. The prostheses were divided into 3 groups according to design (end abutments, unilateral cantilever, and bilateral cantilevers) and the amount of supporting tissues at the time of insertion. On average, only 26% of the total original periodontal tissue remained at the time of insertion. The FPDs consisted of 11 to 14 units, with a mean of 5 to 7 abutments in the 3 groups. The mean periodontal ligament area of the abutments was 79% of the total ligament area of the replaced teeth. RESULTS: At the 3-year follow-up examination, the FPDs were stable in all patients, who in general displayed good oral hygiene and had healthy periodontal conditions. The change in periodontal ligament area over the 3-year observation period was negligible (1 mm(2) per dental unit) and showed no statistically significant difference in relation to FPD design. Most patients were satisfied with the function of their FPDs with respect to mastication, phonetics, hygiene, esthetics, and chewing comfort. A few patients stated that they were careful with the FPDs and avoided certain foods (for example, raw peanuts and grilled squid) because they felt insecure with the cantilever segments. Most patients reported that they would choose the same treatment again. CONCLUSION: Patients with advanced periodontal disease demonstrated successful outcomes over a 3-year period and reported satisfaction with combined periodontal and restorative treatment that included cross-arch FPDs.

Patient evaluation of treatment with fixed implant-supported partial dentures.

The aim of this study was to analyse the patient evaluation of functional treatment outcome in 40 periodontally compromised patients who received implant-supported prostheses (ISPs) as part of the total treatment. The treatment protocol comprised periodontal treatment, extraction of teeth with poor prognosis, placement of dental titanium implants, and after healing, insertion of fixed ISPs. Five of the patients became edentulous in one jaw after extraction of all teeth and received a complete ISP, whereas 35 patients became partially edentulous after extraction of some teeth, 12 receiving a partial ISP on > or = 3 implants, and 23 one on two implants. The follow-up period was on average 1.8 years after the connection of the prostheses, which provided the patients a dentition with a mean of 12 occluding dental units. The first author (S.-W. Yi) performed all implant treatment. Patients' opinions on oral functions--mastication, phonetics, oral hygiene, chewing comfort and aesthetics--were evaluated by means of a questionnaire both before implant installation and at the last follow-up. A control group of 30 subjects with a healthy dentition of 14 occluding natural pairs of teeth answered the same questionnaire on one occasion. A great majority of the patients were extremely satisfied with the oral function after treatment and experienced the ISPs as 'natural teeth'. There was no significant difference between the three treatment groups and the control group for mastication, phonetics, chewing comfort and aesthetics. Patients with ISPs reported a small but significantly greater difficulty with oral hygiene procedures than the controls with natural teeth. Most patients said that they would undergo the treatment again, if necessary, and recommend it to others. It was concluded that the rehabilitation of the periodontally compromised patients, including ISPs on osseointegrated dental titanium implants, resulted in subjectively improved and satisfactory oral function.

Inhibitory effects of helenalin and related compounds on 5-lipoxygenase and leukotriene C(4) synthase in human blood cells.

The sesquiterpene lactone helenalin, which can be isolated from several plant species of the Asteraceae family, is a potent anti-inflammatory and antineoplastic agent. In agreement, alcohol extracts of these plants are used for local external treatment of inflammatory conditions. Since leukotrienes are important mediators in inflammatory processes, the inhibitory effects of helenalin and some derivatives on leukotriene (LT) biosynthesis were studied. Treatment of human platelets with helenalin provoked irreversible inhibition of LTC(4) synthase in a concentration- and time-dependent manner with an IC(50) of 12 microM after a 60 min preincubation. 11alpha,13-Dihydrohelenalin acetate was less potent. Interestingly, individual donors could be divided into two distinct groups with respect to the efficacy of helenalin to suppress platelet LTC(4) synthase. In human granulocytes, helenalin inhibited both the 5-lipoxygenase (IC(50) 9 microM after 60 min preincubation) and LTC(4) synthase in a concentration- and time-dependent fashion. In contrast, the drug was without effect on LTA(4) hydrolase. The GSH-containing adducts (2beta-(S-glutathionyl)-2,3-dihydrohelenalin and 2beta-(S-glutathionyl)-2,3,11alpha,13-tetra hydrohelenalin acetate) did not significantly inhibit LTC(4) synthase. The present results indicate a mechanism for the anti-inflammatory effect of helenalin and related compounds.

Osseintegration following treatment of peri-implantitis and replacement of implant components. An experimental study in the dog.

AIM: The aim of the present experiment was to study if the quality of the titanium surface is a decisive factor for osseointegration and re-osseointegration. MATERIAL AND METHODS: 2 Labrador dogs were used. The mandibular 1st molars and all premolars were removed bilaterally. 3 months later, 1 standard fixture and 3, 2-part "test fixtures" were installed in each side of the mandible. The text fixtures consisted of 1 6-mm long apical and 1 4-mm long coronal part connected with an internal screw. After 4 months, abutment connection was performed. 5 months later, a period of experimental peri-implantitis was initiated during which about 50% of the supporting bone tissue was lost. The dogs were later subjected to a treatment that included (i) systemic administration of antibiotics and (ii) surgical debridement of all implant sites. The abutments and the coronal parts of the text fixtures were removed. All parts of the exposed portion of the standard fixtures, the connecting screw and the apical part of the test fixtures were meticulously cleaned by mechanical means. A pristine, coronal fixture part was via the connecting screw attached to the apical fixture part of each text fixture. All fixtures were submerged. 2 weeks later, a fluorochrome was injected intravenously. After 4 months, biopsies of the implant sites were dissected and prepared for ground sectioning and analysis. RESULTS: It was demonstrated that re-osseointegration failed to occur to implant surfaces (standard) exposed to bacterial contamination, but did consistently occur at sites where a pristine implant component was placed in the bone defect following surgical debridement. CONCLUSION: The above findings seem to imply that the quality of the titanium surface is of decisive importance for both osseointegration and re-osseointegration.

Implant-supported fixed prostheses for the rehabilitation of periodontally compromised dentitions: a 3-year prospective clinical study.

BACKGROUND: The application of a strict hygiene maintenance care protocol following rehabilitation of periodontally compromised dentitions by means of tooth-supported fixed partial dentures has demonstrated excellent long-term treatment outcome. PURPOSE: A clinical and radiographic study was performed to document and evaluate the short- and medium-term result of occlusal rehabilitation by means of implant-supported fixed prostheses (ISFPs) in patients treated for advanced periodontal disease. MATERIALS AND METHODS: Forty-three consecutive patients were included. All patients were referred because of advanced periodontal disease. Before the implant therapy was initiated, periodontal treatment was performed and the outcome evaluated during at least a 6-month period. An individual maintenance care program was designed for each patient. All 125 implants were placed using a two-stage surgical approach. Following installation of the ISFPs, all patients underwent a baseline examination including evaluation of oral hygiene, periodontal or peri-implant conditions, and radiographs. These examinations were repeated annually during the 3-year observation period. RESULTS: No single implant was lost during the 3-year follow-up period. The percentages of plaque-harboring surfaces and bleeding units on probing were found to be low (< 10%), and no soft-tissue complications were recorded. The mean marginal bone resorption during the observation period amounted to 0.21 mm. In a few patients, apposition of marginal bone was observed. Bone loss amounting to 0.5 mm or less was found around 81% of the implants (101/125 implants). The amount of bone loss around the remaining 24 implants (19%) varied between 0.5 and 2.0 mm. CONCLUSIONS: The present clinical trial demonstrates that, at least during a 3-year period, the ISFP is an acceptable and predictable treatment option for rehabilitation in patients who have lost their teeth because of periodontal disease. This observation seems to be valid in edentulous and partially dentate jaws. A prerequisite to reach such a favorable treatment outcome is possibly the combination of the strict maintenance care program and the careful design of the ISFPs.

Marginal bone resorption at different treatment concepts using Brånemark dental implants in anterior mandibles.

BACKGROUND: Different implant treatment modalities, one- and two-step surgery, and one-step surgery combined with early functional loading have successfully been used in the anterior mandible for rehabilitation of edentulism. However, the marginal bone remodeling has not been compared among the three different techniques. PURPOSE: The purpose was to compare the marginal bone level in a short- and long-term perspective study using Brånemark dental implants placed according to either a one- or a two-step surgical procedure or a one-step surgical procedure combined with early functional loading. MATERIALS AND METHODS: Seven patients were treated with a split-mouth technique with a one-step surgical technique on one side and a two-step technique on the other side. In this latter group, the fixtures were submerged during a 3- to 4-month healing period before abutment connection and loading. In 13 patients, following one-step surgery, the permanent prosthetic suprastructure was connected within 20 days from implant surgery. All patients were operated on by the same surgeon. The level of the marginal bone was radiographically measured relative to the fixture-abutment junction and was followed up to 5 years from fixture installation. RESULTS: After connection of the supraconstruction, the marginal bone resorption was significantly lower in the early functional loading group compared to the one- and two-step surgical technique groups. However, after 18 months and after 5 years, the marginal bone was located approximately 1 mm apical to the fixture-abutment level in all three groups. CONCLUSION: There was no difference in marginal bone resorption in a long-term perspective between one- and two-step surgical procedures and a one-step surgical procedure with early functional loading of Brånemark dental implants.

Immediate functional loading of Brånemark single tooth implants. An 18 months' clinical pilot follow-up study.

A clinical and radiographical study was performed to evaluate the treatment outcome of single tooth replacements with artificial crowns retained to implants installed according to a 1-stage surgical procedure and immediate loading (Experimental Group = EG) in comparison to the original 2-stage concept (Control Group = CG). The EG comprised 14 patients (= 14 implants) and the CG comprised 8 patients (= 8 implants), all with single tooth losses anterior to the molars. Beyond the non-smoking criterion the following criteria were adopted: i) the amount of bone had to allow for installation of a fixture with a minimum length of 13 mm and Ø = 3.75 mm, ii) the jaw relationship had to allow for bilateral occlusal stability, iii) the patients should be judged to be non-bruxers, and iv) the patients had to be available for the follow-up and maintenance programme. In the EG a temporary crown was connected to the implant within 24 h following fixture installation. Six months later this crown was replaced with a permanent one. In the CG the surgical and prosthetic treatment followed the standard protocol. Out of the 14 fixtures in the EG 2 were lost up to 5 months in function and were subsequently removed. All remaining 12 implants were stable at every subsequent follow-up examination. No fixture losses were recorded in the CG and all implants in this group were stable at the follow-ups. At the 6-month observation interval all the participating 20 patients were radiographically examined, an examination that was repeated at the 18-month follow-up. The analysis of the radiographs from the EG as well as from the CG disclosed that during the 12-month observation period the mean change of bone support was about 0.1 mm. Further studies, designed as controlled multicenter ones, have to be performed before the results of this pilot study can be recommended for more general use.

Soft tissue response to clinically contaminated and thereafter cleaned titanium surfaces. An experimental study in the rat.

The aim of the present study was to evaluate the soft tissue response to intra-orally exposed and contaminated titanium surfaces (machined, blasted or polished) after being chemically and/or mechanically cleaned. Eight adult Sprague-Dawley rats were used for histomorphometrical and histological analyses. A total of 44 experimental abutments (26 tests and 18 controls) were inserted into abdominal skinpockets of the rats for 6 weeks. No differences regarding the soft tissue response between the different surface characteristics analysed and between test and control could be observed.

Early functional loading of Brånemark dental implants: 5-year clinical follow-up study.

BACKGROUND: Short-term clinical studies have indicated the possibility of one-stage surgery and early loading of machined titanium implants. However, long-term data comparing the outcome to the conventional two-stage technique are missing. PURPOSE: A clinical and radiographic study was performed to compare the outcome of oral rehabilitation of the edentulous mandible by fixed suprastructures connected to implants installed according to either (1) a one-stage surgical procedure and early loading (experimental group--EG) or (2) the original two-stage concept (reference group--RG). The EG and RG comprised 16 and 11 subjects, respectively. MATERIALS AND METHODS: The following specific inclusion criterion were adopted: (1) all patients had to consider themselves to be in good general health, (2) the amount of bone had to enable the installation of five to six, at least 10-mm long fixtures (Mk II fixtures; Nobel Biocare AB, Göteborg, Sweden) between the mental foramina, and (3) the patients had to be available for the follow-up and maintenance program. A total of 88 implants were placed in the EG compared to 30 in the RG. In the EG, fixed appliances were connected to the implants within 20 days following implant installation while the fixed appliances in the RG were connected about 4 months following fixture installation. At delivery of the suprastructures, all patients were radiographically examined, an examination that was repeated at the 18- and 60-month follow-ups. RESULTS: The analysis of the radiographs from the EG disclosed that during the observation period, between 18 and 60 months, the mean loss of bone support amounted to 0.2 mm (SD = 0.4). The corresponding value observed in the RG was 0.0 mm (SD = 0.5). During the 60-month observation period, no fixture was lost in any of the two groups examined. The implants under study as well as those in the reference material were at all observation intervals found to be clinically stable. CONCLUSIONS: This clinical study demonstrated that it is, at least based on a 5-year observation period, possible to successfully load via a permanent fixed rigid cross-arch suprastructure titanium dental implants soon after installation. However, such a treatment approach has to be strictly limited to the interforamina area of the edentulous mandible. Furthermore, the bone resorption was found to be within the same range around such implants as around implants installed and loaded according to the original two-stage protocol.

Chemical treatment of machined titanium surfaces. An in vitro study.

Microbial plaque accumulation on titanium dental implant surfaces can result in an inflammatory condition of the surrounding tissues. Cleaning of such a contaminated surface, in vivo, by means of a solution of amino-alcohol, following surgical exposure, has been proposed. However, the tissue healing following treatment resulted in formation of a fibrous capsule at the tissue-implant interface, i.e. improper implant re-integration. The present experiment was designed to investigate the possible influence of an amino-alcohol solution on machined titanium surface properties. Titanium samples with topography and chemical composition similar to the clinically used Brånemark implant surfaces were used in this experimental in-vitro study to investigate the adsorption of amino-alcohol to such surfaces, and the possibilities to chemically remove the adsorbed alcohols in order to recover a pristine titanium surface. The amino-alcohol solution was supplied to the sample surfaces and four different methods were subsequently used in order to remove the adsorbed alcohol molecules. It was shown that rinsing in water, saline solution, and 5% H2O2 did not remove the amino-alcohol from the surface. However, exposure to ozone produced by using a commercial mercury lamp in ambient air resulted in complete removal of the adsorbed amino-alcohol. The results show that the amino-alcohol used forms a stable and dense film at the implant surface in vitro. Presence of such a film most likely prevents re-integration to occur at the implant-tissue interface in vivo.

Immediate functional loading of Brånemark dental implants. An 18-month clinical follow-up study.

A clinical and radiographical study was performed to compare the outcome of oral rehabilitation in the edentulous mandible by fixed supraconstructions connected to implants installed according to either i) a 1-stage surgical procedure and immediate loading (Experimental Group-EG), or ii) the original 2-stage concept (Reference Group-RG). The EG comprised 16 subjects with edentulous mandibles. Beyond the non-smoking criteria the following specific inclusion criteria were adopted: i) all patients had to consider themselves to be in good general health, ii) the amount of bone had to enable the installation of 5-6, at least 10 mm long fixtures to be bicortically anchored (Mk II fixtures; Nobel Biocare AB, Göteborg, Sweden) between the mental foramina, and iii) the patients had to be available for the follow-up and maintenance programme. A total of 88 implants were placed in the EG (16 patients) compared to 30 in the RG (11 patients). In the EG, fixed appliances were connected to the implants within 20 days following implant installation while the fixed appliances in the RG were connected about 4 months following fixture installation. At the time for delivery of the supraconstructions all 27 patients were radiographically examined, an examination that was repeated at the 18-month follow-up. The analysis of the radiographs from the EG disclosed that during the 18-month observation period the mean loss of bone support amounted to 0.4 mm. The corresponding value observed in the RG was 0.8 mm. During the 18-month observation period no fixture was lost in any of the 2 groups examined. The implants under study as well as those in the reference material were at all observation intervals found to be clinically stable. The present clinical study demonstrated that it is, at least based on an 18-month observation period, possible to successfully load titanium dental implants immediately following installation via a permanent fixed rigid cross-arch supraconstruction. However, such a treatment approach has so far to be strictly limited to the inter-foramina area of the edentulous mandible.

Demonstration of leukotriene-C4 synthase in platelets and species distribution of the enzyme activity.

Human platelets have been demonstrated to possess leukotriene (LT)-C4 synthase activity and may thus be involved in transcellular 5(S)-hydroxy-6(R)-S-glutathionyl-7,9-trans-11,14-cis-eicosatetraenoic acid (LTC4) synthesis. In this study, platelets from seven different species were screened for LTC4 synthase activity. Very high enzyme activity was observed in suspensions of bovine platelets, with approximately 70% conversion of 5(S)-trans-5,6-oxido-7,9-trans-11,14-cis-eicosatetraenoic acid (LTA4) to LTC4. The capacity of equine platelets to produce LTC4 was similar to that of human platelets. In addition, ovine, rabbit, and rat platelets also produced LTC4 after incubation with LTA4. The results demonstrate that LTC4 synthase activity is a common feature among platelets from various species. In contrast, porcine platelets failed to transform LTA4 to LTC4. Instead, these cells produced 5(S),12(R)-dihydroxy-6,14-cis-8,10-trans-eicosatetraenoic acid (LTB4), indicating the presence of LTA4 hydrolase in porcine platelets. A protein with a molecular mass of approximately 18 kDa and LTC4 synthase activity was solubilised from lyophilised bovine platelet concentrates and purified to near homogeneity by affinity chromatography and gel filtration. The N-terminal amino acid sequence of this protein was analysed and found to be almost identical to the corresponding sequence of human LTC4 synthase (17 of 18 amino acid residues identical). Kinetic analysis of partially purified bovine platelet LTC4 synthase revealed Km (for LTA4) and Vmax values of 3.3 microM and 521 nmol x mg protein(-1) x min(-1), respectively. In addition, the presence of a mRNA transcript encoding LTC4 synthase was demonstrated in equine platelets by reverse transcription (RT) PCR using primers derived from the human LTC4 synthase cDNA sequence. Cloning and sequencing of the PCR fragment corresponding to a region near the N-terminus demonstrated very high identity between equine and human leukotriene-C4 synthase in this region. In summary, the present study establishes that platelets contain LTC4 synthase and indicates that this enzyme is widely distributed among platelets from various species.

Some clinical and radiographical features of submerged and non-submerged titanium implants. A 5-year follow-up study.

The present study reports on the results of a follow-up examination of patient material, 5 years after the installation of the fixed supraconstruction. The patient group comprised 11 individuals. Briefly, a split-mouth technique of treatment was used. In the right side of the mandible the traditional 2-step surgical approach for implant installation was used. In the left jaw quadrant a 1-step surgical procedure was used. A clinical and radiographical examination was performed 5 years after the initial connection of the supraconstruction to the implants. At the 5-year follow-up examination all 61 implants examined at the 18-month follow-up were still in service and found to be clinically stable irrespective of the surgical procedure used. Furthermore, the results of the present clinical and radiographical follow-up study demonstrate that the marginal bone level at implants placed anteriorly in the edentulous mandible and supporting fixed supraconstructions is stable between 18 and 60 months irrespective of whether placed according to a 1-step or 2-step surgical procedure.

The effect of antimicrobial therapy on periimplantitis lesions. An experimental study in the dog.

The objective of the present study was to evaluate the effect of systemic antibiotics and local debridement in the treatment of experimentally induced periimplantitis lesions. 5 Labrador dogs, and about 1-year old, were included in the study. In order to establish bilateral recipient sites for implants the mandibular right and left 1st molars, 4th and 3rd premolars were removed. 6 titanium fixtures (Brånemark System Nobelpharma AB, Göteborg, Sweden) were installed and standard abutments were connected 3 months after fixture installation. Cotton floss ligatures were placed in a submarginal position around the neck of the abutments and the animals were placed on a diet which allowed plaque accumulation. After 6-8 weeks, when the tissue destruction amounted to about 20% of the fixture length, the ligatures were removed. 1 month after ligature removal, an antibiotic regimen (amoxicillin and metronidazole) was initiated and maintained for 3 weeks. In the left side of the mandible, buccal and lingual mucoperiosteal flaps were elevated, the granulation tissue within the bone craters adjacent to the implants was curetted, and the abutments were removed. The exposed outer surface, the internal part of the fixtures, as well as the abutments were treated with a detergent, delmopinol. The cleaned abutments were autoclaved, and connected to the clean fixtures. The mucoperiosteal flaps were replaced to their original position, adapted to the abutments and sutured. A careful plaque control program was initiated for the left jaw quadrants. In the right side of the mandible no local treatment was given to the fixtures and the abutments following ligature removal. Furthermore, no plaque control was provided to the implant segments in the right jaws. After 4 months of healing block biopsies including one implant with adjacent hard and soft tissue were harvested and prepared for light microscopy. It was observed that systemic antimicrobial therapy, combined with implant cleaning, curettage of the bone defect and regular plaque control resulted in (i) resolution of the periimplantitis lesion, (ii) a significant recession of the marginal periimplant mucosa, and (iii) a minor additional apical shift of the base of the bone defect. In the untreated sites the plaque associated infiltrate remained and was in several sites examined in contact with the adjacent bone tissue.

Guided bone regeneration in the treatment of periimplantitis.

The objective of the present experiment was to study the soft and hard tissue healing following treatment of experimentally induced periimplantitis. 5 labrador dogs about 1-year old were used. The mandibular right and left 1st molars, 4th and 3rd premolars were removed, titanium fixtures (Brånemark System) were installed, and standard abutments were connected in a 2nd stage procedure. After 3 months experimental periimplantitis was induced by the placement of cotton floss ligatures in a submarginal position. 6 weeks later the ligatures were removed. 1 month after ligature removal, an antibiotic regimen was initiated. During a 3-week period, each dog was given tablets of amoxicillin and metronidazole. In the left side of the mandible, buccal and lingual mucoperiosteal flaps were elevated and granulation tissue within the bone craters curetted. The abutments were removed. The exposed outer surfaces and the internal part of the fixtures were carefully cleaned with a detergent (delmopinol HC1). An e-PTFE membrane was placed over each fixture and adjusted to cover the bone crater. New cover screws were fitted through the membranes to the cleaned fixtures. The implants were submerged and the flaps sutured. In the right side of the mandible no local treatment was performed. The dogs were sacrificed after 4 months and biopsies prepared for histological examination. The findings indicated that treatment of a periimplantitis lesion, including comprehensive systemic antimicrobial therapy and cleaning of submerged implants resulted in (i) the elimination of the inflammatory process in the periimplant tissues and (ii) the establishment of a dense connective tissue capsule in direct contact with the previously exposed surface of the implant system. It was also observed that (iii) new bone was frequently laid down on the pristine cover screws.

Radiographical and histological characteristics of submerged and nonsubmerged titanium implants. An experimental study in the Labrador dog.

Using 5 Labrador dogs, certain characteristics of the peri-implant tissues were analyzed after a 1-step surgical procedure for installation of Brånemark implants. Six titanium implants, in each mandibular quadrant, were installed in the regions of the right and left first molars and the fourth and third premolars. In the right mandibular quadrant, a traditional 2-step procedure was employed, whilst in the left quadrant, a 1-step procedure was carried out. The animals were monitored during a 6-month period. Biopsies of the healed peri-implant mucosa showed signs of superficial inflammation. The histological analysis revealed that i) the connective tissue lateral to the junctional epithelium showed limited accumulations of inflammatory cells (PICT), and ii) that at implant sites that had been exposed to the oral cavity for 6 months (1-step implants), an inflammatory cell infiltrate (abutment ICT) consistently was present in the tissues facing the abutment-fixture junction (AFJ). This infiltrate was separated from the bone crest by a 0.8-mm-wide zone of normal connective tissue. Irrespective of the surgical procedure applied, the radiographic and histometric measurements disclosed that i) the crestal bone loss was about 2.4 mm, ii) the height of the peri-implant mucosa varied from 3.5 mm to 3.9 mm, iii) the bone crest was located 1.1-1.5 mm apical of AFJ as well as of the apical termination of the junctional epithelium (aJE), and iv) a junctional epithelium of 2.1-2.4 mm faced the implant surface. In conclusion, this study demonstrates that, using a dog model, titanium dental implants ad modum Brånemark installed according to a 1-step or to a 2-step surgical procedure will obtain similar soft tissue adaptation and proper bone anchorage (osseointegration). Further studies are, however, required to ascertain the long-term clinical feasibility of the 1-step approach.

Long-term follow-up of cross-arch fixed partial dentures in patients with advanced periodontal destruction: evaluation of occlusion and subjective function.

The study aimed to investigate occlusal factors in fixed partial dentures (FPDs) still in service for more than 10 years, and to assess the patients' opinions regarding oral function with these constructions. Thirty-four patients with 43 FPDs were examined clinically concerning occlusion and by means of a questionnaire on functional aspects. The most common occlusal contact pattern was group function (51% on both sides, 7% on one side) while canine protected occlusion was recorded in 16% on both sides, 7% on one side. Balanced occlusion (19%) was mainly found when the FPD occluded against a complete denture and when there were few abutments and a small amount of abutment supporting tissue. The number and intensity of the occlusal contacts were assessed by means of thin occlusal sheets (50 microns). On average, one occlusal contact was observed on each dental unit with antagonist. The average number of sheets that could be introduced between the antagonists when the patient bit hard in the intercuspal position was two without significant differences between different areas (anterior/posterior) or type of dental unit (abutment, pontics, cantilever section). In the cantilever sections there were looser contacts (more interocclusal sheets) more distally. The great majority of patients were satisfied with the function of their FPDs (mastication, phonetics, aesthetics, comfort, and hygiene). Subjective function was not significantly influenced by FPD design, occlusal factors or number of FPD units. The only significant difference observed was that patients with a small amount of supporting tissues said they had more difficulties with hard foods than the others had. Although a stable occlusion was found in all FPDs, none of the other occlusal parameters examined were related to the long-term results.