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Biomedical subjects

L Blomlöf

Publications and source records attributed to L Blomlöf.

At least 19 recordsLinked to original sources
PubMed1992

Endodontic infection and calcium hydroxide-treatment. Effects on periodontal healing in mature and immature replanted monkey teeth.

Large experimental defects with marginal communication, and small isolated experimental defects were created on the root surfaces of extracted monkey lateral incisors with either open or closed apices. The pulp tissue was either infected or removed, and calcium hydroxide placed in the root canal. The teeth were then replanted and the healing pattern evaluated histomorphometrically after 20 weeks. From the results, it was concluded that (1) an intrapulpal infection promotes marginal epithelial down-growth on a denuded dentin surface irrespective of tooth developmental stage, and that (2) the periodontal healing potential after calcium hydroxide-treatment appears to be higher in teeth with open apices compared with teeth with closed apices, where ankylosis was promoted as opposed to teeth with open apices where significantly more reparative cementum was found.

Animals↗
PubMed1992

Mineralized tissue-formation in periodontal wound healing.

The purpose of the present study was to examine and compare the different mineralized tissues that are found on and around the dental root following treatment of different periodontal pathosis. The material has been compiled from previously published experimental studies on periodontal therapies and trauma treatments. 4 distinctly different appearances of the mineralized tissue layers on the marginal dentin surfaces were described; new cementum, non-attached bone-like tissue, partly attached bone-like tissue and ankylosis preceded by root resorption. It was concluded that, healing in the periodontal/root interface following periodontal therapy may yield different mineralized tissues, depending on a number of host-specific and external factors. The temporal pattern of such healing processes is schematically represented.

Alveolar Bone Loss↗
PubMed1991

Effect of immediate calcium hydroxide treatment and permanent root-filling on periodontal healing in contaminated replanted teeth.

The effect of immediate permanent root-filling and immediate intracanal calcium hydroxide treatment on experimentally contaminated and necrotized periodontal membranes (PDM) in avulsed and subsequently replanted monkey teeth was studied. Almost the entire root surface in the non-endodontically treated control teeth were covered with inflammatory resorption. A significant shift towards ankylosis not associated with root resorption (greater than 80% of the total root surface area) was noted following calcium hydroxide treatment. About two thirds of the root surfaces from the teeth with permanent root fillings showed surface resorptions or ankylosis preceded by root resorption. The root surface area which would have been covered by inflammatory resorption, unless endodontic treatment had been implemented, were instead predominantly covered by either surface resorption (permanent root filling) or ankylosis (calcium hydroxide treatment). Ankylosis compared with surface resorption may in the long term lead to progressive loss of root substance due to replacement resorption. It was concluded that calcium hydroxide may be an excellent initial intracanal treatment in teeth with healthy PDM, but care should be taken not to risk unnecessary development of ankylosis by prolonged treatment of teeth with compromised PDM.

Alveolar Process↗
PubMed1991

Effect of delayed calcium hydroxide treatment on periodontal healing in contaminated replanted teeth.

The effect of delayed intracanal calcium hydroxide treatment on experimentally induced extensive inflammatory root resorption in monkeys was studied. A significant shift from inflammatory resorption to ankylosis was noted following calcium hydroxide treatment. Furthermore, calcium hydroxide treatment appeared to change the pattern of ankylosis over time, although the total ankylotic area remained the same. Ankylosis preceded by root resorption (replacement resorption) increased, while ankylosis not associated with root resorption decreased. It was concluded that intracanal calcium hydroxide treatment of teeth with compromised PDM may cause unnecessary replacement resorption if left in the root canal for a long time or changed repeatedly.

Alveolar Process↗
PubMed1990

Cellular reactions in pulpal and periodontal tissues after periodontal wound debridement.

Periodontal wounds in monkeys were prepared with a bur followed by the application of microbially contaminated cotton pellets. 3 weeks later, the wounds were debrided by scaling followed by etching with citric acid or by treatment with carbonate/peroxidate. The cellular reactions in the periodontal tissues and in the pulp 4, 11, 25, 39 and 53 days after treatment were followed with light microscopy. The marginal periodontium showed heavy inflammatory reactions immediately after treatment, regardless of the debridement procedure. 25 days after debridement, a long epithelial junction had been formed. The apical part of the epithelium deviated from the root surface into the connective tissue, delineating a heavily inflamed part of the connective tissue. After 39 to 53 days, most of the experimental wounds were covered by an epithelial lining. The pulpal reactions were generally limited to a production of irregular dentin on the pulpal wall facing the periodontal wound. It was concluded that the marginal healing pattern following various chemical treatments to the root surface followed, in all essential aspects, conventional treatment with scaling and root planing.

Animals↗
PubMed1989

Influence of granulation tissue, dental calculus and contaminated root cementum on periodontal wound healing. An experimental study in monkeys.

The rôle of gingival granulation tissue, dental calculus and contaminated root cementum in marginal periodontal formation of new attachment was studied experimentally after chemical conditioning of the root surfaces of premolars and molars in 8 monkeys. Each treatment procedure was carried out in 4 monkeys. The other 4 monkeys served as controls. A morphometrical method was used to evaluate the results. It was concluded that a significant amount of new attachment including formation of new adhering cementum will result only on chemically-conditioned cementum surfaces. Small amounts of calculus or granulation tissue left in situ do not seem to influence healing, provided the cementum is left intact after chemical cleansing.

Alveolar Process↗
PubMed1989

Dynamics of dentoalveolar ankylosis and associated root resorption.

The present experimental studies in monkeys were undertaken to study the initiation and progression of dentoalveolar ankylosis of replanted teeth and associated root resorption. Maxillary and mandibular lateral incisors were extracted and replanted after an extraoral period of 15 min or 1 h. Teeth with an extraoral period of 1 h were endodontically treated. Half the number of monkeys were given antibiotics at the time of replantation. The observation periods varied from 2 days to 40 weeks. Irrespective of the length of the extraoral period, initial root resorption and minor areas of ankylosis were found 1 week after replantation. The initial ankylosis was not preceded by root resorption. In teeth replanted after an extraoral period of 15 min the ankylotic area did not increase with increasing time after replantation. Instead the periodontal membrane was re-established, separating the root surface from the alveolar bone. In teeth replanted after an extraoral period of 1 h, the initial ankylotic area increased with increasing time after replantation. Eight weeks and more after replantation, most of the periodontal membrane was replaced by bone covered by osteoblasts and occasional osteoblasts that were in continuity with the endosteal cells outlining the marrow spaces of the alveolar bone. The cementum and dentin were then gradually resorbed with increasing time after replantation. Antibiotics given at the time of replantation reduced the initial inflammation in the periodontal membrane and the inflammatory root resorption after all observation periods and it also seemed to some extent to prevent bacteria from entering the necrotic pulp tissue. Based on the present results it is suggested that root resorption associated with dentoalveolar ankylosis is initiated by endosteal osteoblasts and is thus a hormonally regulated process. This is in contrast to inflammatory root resorption, which seems to be triggered by inflammatory cells.

Animals↗
PubMed1988

Dentin resorption in replanted monkey incisors. Morphology of dentinoclast spreading in vivo.

Dentinoclast colonization of a dentin surface was examined with special reference to changes in plasma membrane morphology during spreading and development into actively resorbing cells. Experimental cavities on the root surfaces of freshly extracted and replanted monkey incisors with infected pulps were examined with scanning electron microscopy after predetermined time intervals. The surface morphology of the dentinoclasts during the different spreading stages, and the fact that the stages appeared in a time-related mode indicated that dentinoclasts follow the general pattern of cell attachment and spreading on solid substrata, with a few exceptions unique to mineralized tissue resorbing cells. As a result, a 3-stage spreading model was proposed. In stage 1, dentinoclasts were characterized by an abundance of filopodia projecting towards the dentin surface. The cells appeared to be exploring the surface to find an area suitable for resorption. This was followed by an increase in cell size accompanied by a progressive disappearance of the peripheral filopod fringe (stage 2). Stage 3 apparently represented the final stage of adaptation and was characterized by an active resorption of the dentin surface.

Animals↗
PubMed1988

Evidence for a role of odontogenic epithelium in maintaining the periodontal space.

Explants of enamel organ epithelium or squamous epithelium from the oral cavity were placed in experimental cavities in the root surfaces of extracted and subsequently replanted monkey incisors. Control cavities without explants were also prepared. After an observation period of 8 weeks, histological evaluation of the cavities originally containing odontogenic epithelium showed a reparative cementum layer on the dentine surface and islands of epithelium in the periodontal connective tissue in the experimental cavities. Bone was not found in the cavities and the alveolar bone had been resorbed around the epithelial islands to a distance corresponding to the periodontal space adjacent to the cavities. Control cavities and cavities originally containing squamous epithelium also showed repair with reparative cementum, but the alveolar bone had grown into the cavities not, however, into contact with the dentine surface. These findings indicate a physiological rôle for odontogenic epithelium, in particular the epithelial rests of Malassez in the periodontal membrane for maintaining the width of the periodontal space and preventing dento-alveolar ankylosis.

Animals↗
PubMed1988

Influence of pulpal treatments on cell and tissue reactions in the marginal periodontium.

The effects of pulpal infection and intrapulpal application of calcium hydroxide and antibiotics were evaluated with special reference to cell and tissue reactions in the marginal hard/soft tissue interface in monkeys. Results indicate the pulpal conditions and endodontic dressings influence marginal healing and repair, provided an endodontic-periodontic pathway such as patent dentin tubules is present. These results suggest that permanent endodontic treatment, with an inert material, should be performed before the protective cementum layer is removed. Pulpally aggravated periodontal lesions should therefore not be overlooked in periodontal diagnosis and treatment.

Animals↗
PubMed1988

A time-related study of healing in the marginal periodontal/root interface.

Healing in a marginal periodontal wound was followed from 1 to 56 days with scanning electron and light microscopy. It was shown that early cell reactions on the root surface involves a plaque-induced inflammation with an apical migration of marginal epithelium, thus preventing connective tissue attachment. New cementum was found only on old cementum in the most apical part of the experimental wound. A temporal morphological baseline was established for further studies on the influence of various local endogenous and exogenous factors on marginal periodontal healing.

Alveolar Process↗
PubMed1987

New attachment in monkeys with experimental periodontitis with and without removal of the cementum.

Experimental periodontitis was induced in monkeys by means of elastic orthodontic ligatures. The periodontally-involved teeth were then treated with different methods. At the end of the treatment period, the monkeys were sacrificed. The premolar-molar areas were dissected out and embedded in a low-viscosity embedding medium (Spurr). The results of the treatment procedures were analyzed on ground sections. Formation of new cementum and new bone was determined by means of tetracycline labeling. Root planing with an ultrasonic device or with hand instruments almost completely removed the cementum and a portion of the peripheral dentin. The root surface was more uneven after treatment with the ultrasonic device than after using hand instruments. No new attachment could be found after root planing. Cleaning of the periodontally-involved root surfaces with two detergents (cetylpyrimidinium chloride and sodium-N-lauroyl sarcosine) without root planing resulted in a significant amount of new attachment.

Animals↗
PubMed1987

Comparative effects of parathyroid hormone on osteoblasts and cementoblasts.

Although bone, dentin and dental cementum are mesenchymal mineralized tissues composed mainly of collagen and hydroxy apatite, they differ markedly in their suceptibility to resorption. Bone undergoes physiological resorption to which the dental tissues appear to be resistant. Recently, the cells covering bone surfaces have been attributed a regulatory role in osteoclastic bone resorption by exposing the bone surface following stimulation with hormones and inflammatory mediators, thereby allowing osteoclasts to colonize the bone surface. In the present study, it was shown that reparative cementum-forming cells covering an experimental cavity in the root surface of replanted monkey incisors were unaffected by parathyroid hormone, a potent mediator of bone resorption. In parallel experiments, endocranial osteoblasts exposed bone surface by widening their inercellular spaces. It was concluded that the layer of cells covering the root surface forms a protective barrier against resorption which serves to preserve the integrity of the dental root.

Animals↗
PubMed1987

Cellular colonization of denuded root surfaces in vivo: cell morphology in dentin resorption and cementum repair.

Cellular colonization of denuded root surfaces on replanted teeth was examined with scanning electron microscopy. The dentin surface was rapidly colonized by a few macrophage-like cells which resorbed dentin in limited areas. They had well-developed ruffled borders but no clear zones. The resorptive activity was gradually inhibited by the ingrowth of a monolayer of fibroblast-like cells from the periphery of the denuded area. At the advancing front, the ingrowing fibroblast-like cells were long and slender, with long tail-like projections trailing the nuclear domain. The invading cells behind these were well-spread and tightly packed. They had a granulated surface and showed morphological signs of fibre synthesis. After 6 weeks, the entire cavity was covered by a monolayer of these cells. Removal of the cells with sodium hypochlorite revealed that a cementum-like tissue had been formed under the invading cells, indicating that they were cementoblasts. It was concluded that wound repair on the root surface is dependent upon the differentiation and proliferation of pre-cementoblasts in the periphery of the wound and that cells in the main body of the periodontal membrane are of little significance in the healing process on the root surface.

Animals↗