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Biomedical subjects

L Blomlöf

Publications and source records attributed to L Blomlöf.

At least 37 records · Page 2Linked to original sources
PubMed1994

Quality of periodontal healing. II: Dynamics of reparative cementum formation.

The purpose of the present study was to follow the formation of mineralised tissue (reparative cementum) on instrumented root surfaces. Twenty-four permanent maxillary and mandibular laterals from six, 3-4-year-old monkeys (macaca fascicularis) were used in the experiment. The incisors were gently extracted and the periodontal membrane (PDM) and cementum on the mesial surface of the roots removed to a distance of 1-2 mm from both the cemento-enamel junctions and the apices of the roots. The teeth were subsequently replanted. Ankylosis was seen both after 3 and 5 wks, although to a lesser degree at 5 wks to be virtually absent at 10 wks. It appeared that the resorptive activity predominant at 5 wks had removed the ankylotic fusion. After 10 weeks, a remaining layer of mineralised tissue, commonly referred to as reparative cementum was seen to cover the denuded dentine surfaces in the present study. It appeared not to be firmly attached to the root surface and did not show a normal cementum-morphology in polarised light. It had a multi-layered appearance resembling alveolar bone tissue and the connective tissue fibres adjacent to the reparative mineralised tissue-layer were not functionally oriented but rather parallel to the root surface. It was concluded that the formation of this mineralised tissue (rearative cementum) was the result of a transient ankylosis.

Alveolar Bone Loss↗
PubMed1994

Quality of periodontal healing. III: Periodontal width following long epithelial junction or reparative cementum formation.

The purpose of the present study was to compare the width of the periodontal space following two different marginal periodontal healing reactions (long epithelial junction and connective tissue healing involving formation of reparative cementum) with the width of normal periodontium, either intact or following reattachment. Twelve permanent lateral incisors in monkeys from a previous experimental study on periodontal wound healing on denuded surfaces were selected based on strict healing criteria. The periodontal width was measured histomorphometrically and compared to the periodontal width on the contra lateral side of the same root where reattachment had taken place and with the width of normal periodontal space of neighbouring untreated teeth. The mean periodontal width for both after formation of a long junctional epithelium and reparative cementum were significantly larger than the control width, approximately 290%. This may be taken as evidence of an impaired functional adaptation of the reparative tissue compared to a reestablished or normal periodontal membrane.

Animals↗
PubMed1994

Quality of periodontal healing. IV: Enzyme histochemical evidence for an osteoblast origin of reparative cementum.

The aim of the present study was to map the distribution of healing gingival and periodontal connective tissue well as osteoblastic activity in marginal periodontal wound healing using activity of alkaline phosphatases as markers. Activity of non-specific alkaline phosphatase (NSAP) was abundant in periodontal but not in gingival connective tissue. Activity of vanadate-resistant alkaline phosphatase (VRAP) had a preferential localisation to periosteal and endosteal bone surfaces but was not detectable in cementoblasts along root surfaces. However, following spontaneous marginal healing of exposed dentine surfaces, activity of VRAP was also found on healing dentine surfaces. It was concluded that osteoblasts rather than cementoblasts form reparative cementum on exposed dentine surfaces during marginal periodontal healing.

Alkaline Phosphatase↗
PubMed1993

Relationship between periapical and periodontal status. A clinical retrospective study.

The purpose of the present investigation was to explore possible relationships between clinical periodontal status in periodontally involved teeth with and without endodontic infection. The investigation was conducted as a retrospective study on a consecutive referral population. The periapical conditions in endodontically-involved single-rooted teeth from a selected patient sample were evaluated and correlated to their periodontal status. There was a significant correlation between periapical pathology and vertical bony destructions. An intra-individual comparison between pocket depth in teeth with and without periapical pathology showed that periapical pathology was significantly correlated to an increased pocket depth in the absence of a vertical bony destruction. It was concluded that an endodontic infection, evident as a periapical radiolucency, promotes periodontal pocket-formation on an instrumented marginal root surface and, consequently, should be regarded as a risk factor in periodontitis progression and be given appropriate consideration in periodontal treatment planning.

Adult↗
PubMed1993

Periodontal healing in teeth with periapical lesions. A clinical retrospective study.

The purpose of the present investigation was to compare clinical periodontal healing in periodontally involved teeth with and without pulpal pathosis. The investigation was conducted as a retrospective study on a consecutive referral population. The periapical conditions in endodontically involved single-rooted teeth from a selected patient sample were evaluated and correlated with their periodontal healing pattern. Multiple regression analysis of the registered variables showed that initial mean pocket depth and time elapsed after treatment significantly influenced change in pocket-depth. Non-surgical treatment of periodontal pockets exceeding 2.5 mm in teeth with horizontal marginal defects, over the observation period, showed significantly reduced mean pocket depth reduction in teeth with periapical pathology compared to teeth without periapical pathology. It was, furthermore, evident that proximal restorations, abutments for fixed bridges and root fillings with and without dowels did not significantly influence pocket depth reduction in the present material. It was concluded, based on the present results, that a root-canal infection, evident as a periapical radiolucency, if left untreated may in the long term perspective result in retarded or impaired periodontal healing following periodontal therapy and, consequently, should be given appropriate consideration when coordinating endodontic therapy and periodontal treatment.

Adult↗
PubMed1993

Successive removal of periodontal tissues. Marginal healing without plaque control.

The aim of the present study was to compare periodontal healing after successive removal of periodontal tissue components, from the alveolar bone to the dentin surface. The prevailing tissue reaction when adhering PDM was left on the exposed roots was that most of the bone tissue that had been removed from the buccal surfaces had regenerated and the integrity of the PDM between the new alveolar bone and cementum surface had been reestablished. On exposed etched cementum surfaces, 2 prevailing healing results were recorded. In half the number of the roots, the root surfaces were covered by connective tissue with fibers running parallel to the root surfaces in a capsule-like arrangement. The other prevailing reaction was a thin epithelial cell-lining running parallel to the root surfaces in close contact or partly penetrating the adjacent connective tissue. On exposed denuded dentin surfaces, gingival retraction was a constant finding, associated with an epithelial cell-lining of varying thickness sometimes with rete pegs and cyst-like formations. Gingival retraction was also a constant finding on etched dentin surfaces. This was associated with pathological pockets outlined by epithelial cell-layers of varying thicknesses. The significance of these findings were discussed with special emphasis on dynamics of recurrent periodontitis.

Acid Etching, Dental↗
PubMed1993

Development of periapical lesions.

The purpose of the present study was to follow the development of periapical lesions both radiographically and histologically in infected teeth with open and sealed root canals. The mandibular premolars from five adult monkeys were used in the experiment. Sealed infected teeth developed radiographic signs of periapical pathosis significantly earlier than unsealed teeth. Although, histological signs of pathology could be seen periapically at earlier observation periods, sealed teeth consistently developed these changes earlier than unsealed teeth. Furthermore, the histological periapical pathology differed somewhat between the two groups in that unsealed teeth showed a multi-focal diffuse pattern of spreading.

Animals↗
PubMed1993

Tissue formation on cementum surfaces in vivo.

The purpose of the present investigation was to study cell colonization of and tissue formation on denuded (anorganic) cementum surfaces as well as denuded demineralized cementum surfaces. The most conspicuous finding was the distinctly different pattern of cell colonization and subsequent tissue formation on etched and non-etched denuded cementum surfaces. Non-etched cementum surfaces displayed a limited number of resorbing cells and resorption lacunae, while etched cementum surfaces displayed an abundance of fibroblast-like cells in varying stages of activity in a meshwork of fibres, probably collagenous. These fibres were organized in a layer parallel to the root surface. This appearance of a fibrous capsule-like structure has previously been associated with periodontal healing with a non-functional repair-tissue. It may be concluded, based on the present results that, a cementum surface in which collagen fibers have been exposed presents a suitable surface for colonization by mesenchymal cells. However, if collagen fibers are not exposed in the cementum surface leaving mineralized surface, mesenchymal cells appear not to be able to attach.

Acid Etching, Dental↗
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↗