Biomedical subjects

I Ericsson

Publications and source records attributed to I Ericsson.

At least 37 records · Page 2Linked to original sources

PubMed1995

Different types of inflammatory reactions in peri-implant soft tissues.

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)

Alveolar Bone Loss↗

PubMed1995

The periodontal ligament of teeth connected to osseointegrated implants. An experimental study in the beagle dog.

The aim of the present investigation was to analyze the periodontal tissues at immobilized teeth connected to osseointegrated implants. 10, 1-year old beagle dogs, were used. Bilaterally, the mandibular 2nd (2P2) and 3rd premolars (3P3) and 1st molars (1M1) were extracted. 2 titanium fixtures were installed in the edentulous segment of the right side of the mandible, one about 10 mm mesial and the other about 10 mm distal to 4P (test tooth). 3 months later, abutment connection was performed and healing allowed for one month. The dogs were randomly divided into 2 groups of 5 each, group A and group B. In group A, a fixed gold splint, rigidly connecting the tooth and the 2 implants, was installed on day 0 and 4P was hereby immobilized. The controlateral 4th premolar (P4) served as the non-splinted control tooth. Plaque control measures continued until the end of the experiment (day 180). In group B, plaque control measures were abandoned 1 month after abutment connection and a 4- month period of experimental periodontal tissue breakdown was initiated. This was accomplished by placing cotton floss ligatures submarginally around 4P and P4. At the end of this 4-month period, the ligatures were removed, and an apically positioned flap procedure was performed. Healing was allowed for another 2 months. Plaque control measures were re-established and continued throughout the experiment. A given day was termed day 0 and 4P was rigidly connected to the adjacent implants in the manner described for group A.(ABSTRACT TRUNCATED AT 250 WORDS)

Alveolar Process↗

PubMed1995

Resolution of ligature-induced peri-implantitis lesions in the dog.

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)

Alveolar Bone Loss↗

PubMed1995

Periodontal ligament tissue reactions to trauma and gingival inflammation. An experimental study in the beagle dog.

The aims of the present study were to analyze (i) which tissue changes may occur in the zone of co-destruction to better understand why trauma from occlusion may induce additional attachment loss, and (ii) whether changes occur in the periodontal ligament tissue when an inflammatory lesion (ICT) approaches the periodontal ligament space. 16, 1-year-old beagle dogs, were selected and divided into 2 groups, group A and group B, consisting of 6 and 10 dogs, respectively. In group A, on day 0, a bucco-lingual jiggling type movement was induced resulting in increasing tooth mobility at P3 (test tooth) by the application of an orthodontic elastic which traversed the buccal surface of the crown of the test tooth. The elastic was exchanged either in a buccal or in a lingual position 2x a week during a 3-month period. 3P served as non-jiggled control tooth. Tooth mobility measurements were recorded on days 0, 30, 60, 90. A plaque control regimen was maintained until the end of the experiment (day 90). On day 90, biopsies including P3 and 3P were harvested. The dogs representing group B, were divided into 2 subgroups of 5 each, group BI and group BII. On day 0, a 4-month period of experimental periodontal tissue breakdown was initiated by placing cotton floss ligatures submarginally around the mandibular fourth premolars (4P4) in group BI and around the mandibular third premolars GP3) in group BII. All ligatures were exchanged, replaced 1x every month, and on day 120 permanently removed. On the same day, biopsies included 4P4 were harvested. Following supragingival debridement 3P3 were allowed to accumulate plaque until the end of the study (day 225). On this occasion, biopsies including 3P3 were harvested. The results of the histological measurements revealed that in the most coronal portion of the periodontal ligament of teeth exhibiting increasing mobility, there was an increased width, a reduced % tissue volume of collagen, and an increased volume of vascular structures and leukocytes. Furthermore, the number of osteoclasts bordering this portion of the alveolar bone was increased and the number of collagen fibers inserting into the root cementum and into the alveolar bone was reduced. It was also demonstrated that in teeth with normal mobility, the position of the gingival ICT failed to influence the composition of the tissue within the coronal portion of the periodontal ligament.

Alveolar Process↗

PubMed1995

Long-term follow-up of cross-arch fixed partial dentures in patients with advanced periodontal destruction. Evaluation of the supporting tissues.

The aim of the study was to evaluate the periodontal conditions in patients treated more than 10 years ago for advanced periodontal disease and rehabilitated with cross-arch fixed partial dentures (FPDs). Of 50 randomly selected patients, 34 subjects carrying 43 FPDs agreed to participate in a clinical and radiographic follow-up examination. The FPDs were divided into three groups on the basis of prosthesis design (end abutments, unilateral cantilever, and bilateral cantilevers) and amount of supporting tissues at the time of bridge installation. Seventy per cent of the FPDs were found to be unchanged, whereas the rest had been modified due to various complications leading to extraction of one or more of the abutment teeth. Six FPDs (14%) had been partially replaced by FPDs anchored to osseointegrated dental implants. A total of 21 (8%) of the original 274 abutment teeth had been extracted. Longitudinal changes in the amount of periodontal support were minimal over the average of 15 years of follow-up. FPD design or initial amount of supporting tissues was found not to have significant influence on longitudinal changes in periodontal conditions. It was concluded that combined periodontal and prosthodontic treatment of patients with advanced loss of periodontal support may provide a high rate of long-term successful outcome, provided proper adequate periodontal and prosthetic treatment and maintenance care are given.

Aged↗

PubMed1994

Clinical and radiographical features of submerged and nonsubmerged titanium implants.

A clinical and radiographical study was performed to evaluate whether initial submergence of titanium fixtures is an obligate treatment measure for the establishment of proper bone anchorage when implants a.m. Brånemark are used. The sample was comprised of 11 subjects with edentulous mandibles. A split-mouth design was employed; in the right mandibular quadrant a traditional 2-step procedure for fixture installation and abutment connection was utilized, while in the left quadrant a 1-step procedure was carried out, i.e., fixtures were placed and abutments were connected in one and the same session. Three to 4 months after fixture installation, fixed bridgeworks were fabricated and rigidly connected to the implants. Clinical examinations (including probing pocket depth, bleeding on probing and implant stability test) were performed after 12 and 18 months. Radiographs were taken following insertion of the bridges and at the 12- and 18-month re-examinations. The probing pocket depth, the bleeding on probing, the implant stability and the radiographic determinations were similar for the 2 groups of treatment alternatives. This indicates that titanium fixtures a.m. Brånemark can be properly anchored (osseointegrated) in mandibular bone and successfully used for bridge retention also when a 1-step procedure is used for implant installation.

Adult↗

PubMed1994

A histomorphometric evaluation of bone-to-implant contact on machine-prepared and roughened titanium dental implants. A pilot study in the dog.

This investigation was performed to assess the bone-to-implant surface contact at fixtures of titanium that either had a standard machine prepared or a TiO2-blasted surface. Five beagle dogs were used in the experiment. Extractions of the premolars were performed in the maxilla. After 4 months of healing, 5 standard machine-prepared fixtures and 5 prepared according to the TioBlast technique were inserted. Two months later another 5 "standard" and 5 TioBlast-prepared implants were inserted. Four months after the first fixture installation, the animals were killed and ground sections prepared from each implant site. Of the 20 implants installed, 19 were successfully incorporated. The mean bone-to-implant surface for "standard" fixtures was about 40% both at the 2 and 4 months observation interval. The corresponding figures for the TioBlast-prepared fixtures were similar during the first 2 months of observation, while subsequently the TioBlast-prepared fixture surface seemed to stimulate to a more close bone-to-implant contact (65%) than the "standard" one.

Analysis of Variance↗

PubMed1994

The topography of the vascular systems in the periodontal and peri-implant tissues in the dog.

The present investigation reports an animal experiment the objective of which was to study the vascular topography of the periodontium and the peri-implant soft and hard tissues in the beagle dog. 2 beagle dogs were used. The right mandibular premolars were extracted and healing allowed for 3 months. 2 titanium fixtures a.m. Brånemark were installed in the right premolar region. Abutment connection was performed 3 months later. The contra-lateral mandibular sites were used as tooth harboring control units. A 4-month period of meticulous plaque control was initiated. A clinical and radiographical examination was performed towards the end of this period and revealed that the gingiva and peri-implant mucosa were clinically healthy and that the bone tissue at teeth and implants had a normal height. The carotid arteries were perfused with a mixture of carbon and calf serum. 2 bucco-lingual sections, about 100-150 microns thick, and one mesio-distal section comprising the junctional epithelium and underlying connective tissue were sampled. The sections were treated, cleared and examined in a microscope. The results of the present investigation demonstrated that the vasculature of the gingiva and the supracrestal connective tissue at teeth is derived from two sources, namely the supraperiosteal vessels lateral of the alveolar process and the vessels of the periodontal ligament. The blood vessels of the peri-implant mucosa were found to be terminal branches of larger vessels originating from the periosteum of the bone of the implant site.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Tooth mobility and resolution of experimental periodontitis. An experimental study in the dog.

The aim of the present experiment was to study alterations in the mobility of teeth that occurred during resolution of experimentally induced periodontitis lesions in the dog. 5, 1-year-old, beagle dogs were used in the study. The left and right 4th, 3rd, and 2nd mandibular premolars (4P4, 3P3, 2P2) served as experimental teeth. Periodontal tissue breakdown was initiated by placing plaque-collecting cotton-floss ligatures around the neck of the experimental teeth. The ligatures were replaced to the level of the receding gingival margin 1 x every month. On Day 120, the ligatures were removed and debridement was performed. A groove, parallel to the long axis of the mesial root, was prepared in the mesio-buccal surface of the crowns of 2P and P2. Guided by the groove and with a probing force of 0.5 N, a probe was inserted into the buccal gingival pocket of the mesial root and was attached to the buccal surface. Biopsies including both the mesial and distal root of 2P and P2 and the surrounding hard and soft tissues were harvested. The biopsy procedure was repeated in a similar manner 15 days (i.e. Day 135) and 3 months (i.e. Day 225) after ligature removal in the 4th (4P4) and 3rd (3P3) premolar regions. After fixation, decalcification and sectioning, the biopsy material was exposed to histometric and morphometric measurements. Assessment of the mobility of the experimental teeth was performed on Days 120, 135 and 225 using the Periotest system.(ABSTRACT TRUNCATED AT 250 WORDS)

Alveolar Bone Loss↗

PubMed1993

Progression of periodontal tissue destruction at splinted/non-splinted teeth. An experimental study in the dog.

The aim of the present investigation was to study whether splinting, i.e., immobilisation of teeth, may interfere with the rate of periodontal tissue destruction that can be accomplished by ligature placement and plaque accumulation, 5, 1-year-old, beagle dogs were included in the experiment. The mandibular 2nd and 3rd premolars and the 1st molar on both sides of the mandible were extracted. 2 titanium implants were installed in the sites of 3P and 1M, i.e., in the right quadrant of the mandible. 3 months later, abutment connection was performed and a fixed, gold splint, connecting the tooth and the implants, was inserted. The non-resilient splint was cemented in place on Day 0 and 4P was hereby immobilized. In each dog, the contralateral fourth premolar (P4) served as the non-splinted control tooth. Experimental periodontal tissue breakdown was initiated by placing cotton floss ligatures around the neck of 4P and P4 and by allowing the animals to accumulate plaque and calculus. Once every month, new ligatures were placed at the level of the receding gingival margin. The experiment was terminated on Day 180. Radiographs of 4P and P4 were obtained and biopsies sampled. The results of the measurements, made in the radiographs and the histological sections, disclosed that the splinting of the experimental teeth, failed to prevent or retard apical downgrowth of plaque and associated attachment loss. It was concluded that increased tooth mobility, within the limits of the present experiment, obviously did not establish conditions which favoured an enhanced destruction of the periodontal tissues in the beagle dog model.

Alveolar Bone Loss↗

PubMed1993

Probing depth at implants and teeth. An experimental study in the dog.

The aim of the present investigation was to assess the resistance offered by the gingiva at teeth and the peri-implant mucosa at osseointegrated titanium implants to mechanical probing. 5 beagle dogs were used in the experiment. The 2nd and 3rd premolars and the 1st molars of the right and left mandibular dentition were extracted. 2 titanium implants were installed in the edentulous right and left premolar- and molar-regions. Abutment connection was performed 3 months later. The remaining premolar in the left jaw (P4) was exposed to "experimental periodontitis" during a 4-month period and, thus, the 4th premolar in the right jaw (4P) was representing healthy periodontium. The inflamed soft tissues at P4 were treated using a flap procedure. Following 2 weeks of healing, the main experiment was started, i.e., day 0. During the subsequent 360 days, the teeth and abutment parts of the implants were regularly exposed to plaque control (3 x/week). Radiographs of 4P-, P4- and the implant-regions were obtained on days 0 and 360. Mobility measurements were performed on days 0 and 360. Biopsies of the experimental teeth and the implants were sampled at the end of the study. The results of the present experiment demonstrated that differences in terms of tissue composition, organization and attachment between the gingiva and the root surface on one hand and between the peri-implant mucosa and the implant surface on the other, make the conditions for probing depth measurements at teeth and implants different.(ABSTRACT TRUNCATED AT 250 WORDS)

Alveolar Process↗

PubMed1992

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.

Animals↗

PubMed1992

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.

Alveolar Bone Loss↗

PubMed1992

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.

Animals↗

PubMed1992

Putative periodontal pathogens on titanium implants and teeth in experimental gingivitis and periodontitis in beagle dogs.

The microflora around titanium implants and teeth in 4 beagle dogs was analyzed in order to follow the longitudinal development from healthy conditions to experimental gingivitis and periodontitis. A 2-month plaque control program was performed to establish healthy conditions on titanium implants and control teeth (baseline, day 0). Subgingival bacterial samples and radiographs were obtained. The plaque control was ceased and all measurements were repeated on day 21 (gingivitis). A new period of plaque control was initiated to re-establish healthy conditions (day 49). A cotton ligature was placed subgingivally around the implants and the control teeth to induce tissue breakdown. The ligatures were removed on day 91. The study was completed with registrations on day 121 (periodontitis). No significant microbiological difference was found between titanium implants and teeth in healthy conditions and in gingivitis and periodontitis. The mean total viable count increased 10 times on implants as well as on teeth. Streptococci were dominating at baseline: 40.2% on implants and 60.6% on teeth and decreased in gingivitis to 11.7% and 5.4%. When periodontitis had developed, the proportion of streptococci was < 1%. At baseline few Porphyromonas gingivalis and Prevotella intermedia were detected. They increased at gingivitis to 37.4% and 21.0%; when periodontitis developed, they comprised about 25.0%. Microbial colonization and establishment on titanium implants with healthy gingiva, experimental gingivitis and periodontitis follow the same pattern as on teeth.

Animals↗

PubMed1992

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)

Animals↗

PubMed1992

Guided tissue regeneration in surgically-produced furcation defects. An experimental study in the beagle dog.

The aim of the investigation was to evaluate the potential for new attachment formation at various degree III furcation involvements in the beagle dog. 3 differently shaped furcation defects were prepared; one small and one large key-hole defect, and one furcation defect which was part of "circumferential" loss of attachment and bone. 15 beagle dogs were used in the experiments. The furcation defects were surgically created at mandibular premolars in the right and left side of the jaw. Test teeth were subsequently treated according to the GTR principle, while control teeth were treated without the application of membranes. The result from the histological examination of biopsy specimens revealed that GTR treatment may result in complete new attachment at surgically produced "through and through" furcation involvements in dogs. The study, however, also revealed that the size of the furcation defect as well as the shape of the surrounding alveolar bone were factors that determined the outcome of this kind of treatment. The treatment failures were consistently associated with flap recession during healing which resulted in the exposure of the furcation defect.

Alveolar Bone Loss↗

PubMed1992

Probing pocket depth at mobile/nonmobile teeth.

The aim of the present investigation was to study the influence of an increased tooth mobility on the resistance offered by the periodontal tissues to probing. 6 beagle dogs were used. At the start of the experiment, the animals had clean teeth and normal gingival and periodontal conditions. In each dog, a device was installed in the lower left jaw quadrant to expose the third premolar (P3) to jiggling forces which would enhance the mobility of this "test" tooth. The contralateral tooth served as the non-jiggled control. During the 3 months of experimentation, the teeth of the dogs were cleaned on a regular basis. Clinical examinations including tooth mobility measurements were performed on days 0 and 90. After the examination on Day 90, a probe was inserted in the buccal "pocket" of the mesial root of 3P and P3. The probe was retained with composite. Biopsies including the test or control tooth with adjacent buccal periodontal tissues were harvested, fixed and decalcified. Each biopsy was divided in one mesial and one distal portion (root). The distal portion was embedded in Epon, sectioned and stained in PAS and toluidine blue, while the mesial portion, following probe removal was embedded in paraffin, sectioned and stained in hematoxylin-eosin. The sections were exposed to histometric and morphometric measurements. The findings demonstrated that tissue alterations which occur at mobile teeth may reduce the resistance offered by the periodontal tissues to clinical probing. Such alterations include (i) reduced height of the alveolar bone, (ii) reduced amount of collagen, and increased vascularity in the enlarged supracrestal connective tissue.

Animals↗