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PubMed1982

Periodontal healing following open debridement flap procedures. II. Histologic observations.

Four tooth-containing blocks were obtained from patients being treated for infraosseous lesions of significant depth as part of their periodontal therapy. Treatment consisted of open flap debridement and professional cleansing at least every 4 weeks. Teeth in block were removed for histologic study 4 to 6 months after surgery. Histologic evaluation of the repair process showed pocket closure by epithelial and connective tissue adhesions in the form of an elongated junction epithelium, beneath which parallel-oriented fibers adhered to the root for a limited distance. Apical to this adhesion, functionally inserted fibers were present. Since no cementogenesis was seen at these latter areas, it must be assumed that the inserted fibers were present before the surgery and were not significantly affected by the procedure. No significant evidence of crestal osteogenesis was noted. However, comparison of the clinical osseous profile recorded at the time of surgical debridement with the flat crest seen in two of our cases histologically, suggests that significant crestal resorption had taken place postsurgically in some of these lesions.

Adult↗
PubMed1993

Small versus large particles of demineralized freeze-dried bone allografts in human intrabony periodontal defects.

Various particle sizes of demineralized freeze-dried bone allograft (DFDBA) are currently used to treat patients with periodontal osseous defects. However, the effect of particle size on the healing of human intrabony periodontal defects is unknown since there have been no direct clinical comparisons. The purpose of this study was to compare the bony defect resolution obtained using two different particle size ranges of DFDBA. Cortical bone from a single donor was processed and ground to final particle sizes of 250 mu to 500 mu or 850 mu to 1,000 mu using an analytic mill. Paired interproximal intrabony periodontal defects in 11 patients were grafted with DFDBA. Soft and hard tissue measurements were made using an electronic constant-force probe at the initial and reentry surgeries. Treated sites in 10 patients were reevaluated by reentry approximately 6 months postoperatively. Mean bony defect fill was 1.66 mm for the large particle group and 1.32 mm for the small particle group. There was no statistically significant difference in bony fill between defects grafted with the different particle sizes of DFDBA when used in humans.

Adult↗
PubMed2004

Spatial and temporal localization of secretory IgA in healing tooth extraction sockets in a rabbit model.

PURPOSE: The purpose of this study was to look at the spatial and temporal localization of secretory IgA in healing tooth extraction sockets in a rabbit model. MATERIALS AND METHODS: Twenty-four male New Zealand White rabbits were used in the study. Incisor teeth were extracted from both jaws, and the healing extraction socket with the surrounding jaw bone was harvested at 48 hours, 4 days, and 1, 2, 4, 8, 12, and 16 weeks. Tissues were fixed, decalcified, and processed for hematoxylin and eosin and immunohistochemical staining. The sections were stained to detect secretory IgA. The stained sections were then imaged, and an automated computer program was used to detect the brown 3,3'-diaminobenzidine stain that represented the secretory IgA. The data were obtained in the form of percentage area and intensity of stain and analyzed using analysis of variance (Tukey-Kramer and Scheffé's tests). RESULTS: Spatial and temporal differences in localization of secretory IgA were observed across time frames in both jaws. CONCLUSION: The results of this study showed definite trends in the spatial and temporal localization of secretory IgA in healing tooth extraction sockets in a rabbit model.

Alveolar Process↗
PubMed1987

Histologic study of healing of human periodontal defects after placement of porous hydroxylapatite implants.

Two intrabony pockets on teeth that were to be extracted for prosthetic reasons, in two patients, were treated by means of papilla preservation flaps and implantation with porous hydroxylapatite. The teeth, with a portion of their periodontium, were extracted 5 and 6 months after treatment and processed histologically. Both cases showed the implants invaded by connective tissue, which was actively forming bone. There was no inflammatory reaction triggered by the implant material, although there was some recurrence of inflammation in the vicinity of the pocket wall. The junctional epithelium in both cases extended slightly beyond the coronal level of the implant. One of the cases had an abundant new cementum formation with fibrous tissue next to the implant, that appeared to be a rebuilt attachment of collagen fibers. Although some multinucleated giant cells were found in the pores and next to the newly formed bone, the implanted material did not appear to be resorbed in the period of time studied.

Adult↗
PubMed1983

Clinical and histological characteristics of lyophilized allogenic dura mater in periodontal bony defects in humans.

This clinical and histological study investigated the use of lyophilized, allogenic dura mater (Lyodura) as a periodontal implant material in interdental bony defects (2-wall lesions) in humans. For 23 defects in 8 subjects a modified Widman flap was raised, curettage performed and the defects bridged with the implant. The same procedure, without Lyodura implantation, was performed on 23 contralateral teeth. By a standardized method, involving the use of a removable stent, the following clinical measurements were recorded after 24 and 48 weeks: the probing attachment level, the probing bone level, the probing pocket depth and the labial and interdental gingival recession. For the histological study 5 additional, interdental craters and 5 control defects were treated as in the clinical study. They were block-sectioned after 1, 2, 6, 12 and 24 weeks and processed in the usual manner for routine examination by light and polarization microscopy. From the clinical study it could be concluded that, in absolute values, only the experimental side showed a significant gain in probing attachment level and a greater reduction of the probing pocket depth. In percentage values the labial gingival recession was significantly lower and the bone formation significantly more pronounced on the experimental side. The histological examination showed that the implant remodelled completely without rejection phenomena. It was replaced gradually, after enzymatic breakdown, by the host's own collagen through the action of invading fibroblasts. Bone formation occurred along but never in the implant. The implant material seems to act as a barrier against epithelial downgrowth and infiltration of inflammatory cells.

Adult↗
PubMed1992

Light and transmission electron microscopy of the intact interfaces between non-submerged titanium-coated epoxy resin implants and bone or gingiva.

This experiment was aimed at studying the intact tissue/implant interface of non-submerged dental implants with a titanium surface. Epoxy-resin replicas were fabricated from 3.05 x 8 mm cylindrical titanium implants with a plasma-sprayed apical portion and a smooth coronal collar. The replicas were coated with a 90-120-nm-thick layer of pure titanium and autoclaved. The coated replicas were inserted as non-submerged endosseous implants in the edentulous premolar region of dog mandibles and allowed to heal for three months. Jaw sections containing the implants were processed for light and electron microscopic study of the intact tissue/implant interface with and without prior demineralization. Gingival connective tissue fibers were closely adapted to the titanium layer, in an orientation more or less parallel to the implant surface. There was no evidence of any fiber insertions into the surface irregularities of the smooth or rough titanium surface. Undemineralized bone was intimately adapted to the titanium surface without any intervening space. In demineralized sections, the collagen fibers of the bone matrix tended to be somewhat thinner and occasionally less densely packed in the vicinity of the implant surface. However, they extended all the way to the titanium surface, without any intervening fibril-free layer.

Alveolar Process↗
PubMed1989

Histological evaluation of periodontal probe penetration in untreated facial molar furcations.

The purpose of this investigation was to histologically determine the position of the periodontal probe tip when probing the deepest interradicular pocket depth in grade II and III facial molar furcation sites. Facial furcation pockets (5.8 mm +/- 1.3) were probed with a pressure-sensitive probe set at 50 g pressure. The probe tip was attached to the tooth with an acid etched composite resin. Surgical block biopsies were removed, fixed, decalcified and processed for histological sectioning. Buccolingual serial sections (6 mu) were cut from 9 biopsies and apicocoronal serial sections were cut from 3 biopsies. The sections were histometrically analyzed. The probe tip penetrated the inflamed furcation connective tissue an average depth of 2.1 mm (+/- 0.6). The probe tip was located 0.4 mm (+/- 1.4) apical to the crest of the interradicular bone. The % of inflammatory cell infiltrate in the connective tissue (ICT) around the probe tip was 56% (+/- 15%). There was no correlation between the % of ICT and the depth of probe penetration. This investigation demonstrated that probing of untreated facial molar furcation sites does not measure the attachment level of the interradicular root surfaces, but rather records the depth of probe penetration into the inflamed furcation connective tissue.

Alveolar Process↗
PubMed1997

Abscess formation around a hydroxyapatite-coated implant placed into the extraction socket with autogenous bone graft. A histological study using light microscopy, image processing, and confocal laser scanning microscopy.

The purpose of this study was to evaluate the radiologic, histologic, and histometric findings for a retrieved hydroxyapatite (HA)-coated implant which had been placed into a fresh extraction socket with autogenous bone graft 3 months previously. A periapical radiography disclosed a vertical bone loss around the implant cervix. Examination of histologic section disclosed that granulation tissue including bone chips around the cervix, and newly-formed bone tissue around the grafted bone tissue on the HA coated surface. In the confocal laser scanning microscopic findings toluidine blue-negative bone tissue showed autofluorescence. Histometric analysis indicated that the average percent bone contact was 29.2% (ranged 26.4% to 34.1%). Suspected reasons for failure were an early exposure of the barrier membrane, its early removal, the implant placement into an infected site, inadequate antibiotic premedication, and/or poor control of infections around teeth prior to implant surgery and around implants before and after placement of barrier membrane.

Abscess↗
PubMed2001

Bioabsorbable materials for guided bone regeneration prior to implant placement and 7-year follow-up: report of 14 cases.

BACKGROUND: The purpose of the present study was to evaluate the efficacy of a guided bone regeneration (GBR) procedure prior to implant placement and the long-term outcome of the inserted implants. METHODS: Prior to dental implant placement, GBR procedure was performed on 14 patients (mean age 48 years) using a synthetic hydroxyapatite (HA) spacer under a collagen membrane. After a mean healing period of 8 months, bone biopsies were obtained during the placement of 14 implants. The specimens were processed for histology without demineralization in order to assess bone quality and quantity of the regenerated bone. RESULTS: Both the bone density and the resorption degree of HA particles were relatively varied between samples. The different phenotypes of osteoclasts and multinucleated giant cells and the individual host response could partially explain the unpredictable results in terms of bone remodeling and biomaterial resorption. However, the presence of HA particles in the regenerated bone had no influence on the osseointegration of implants presenting a success rate of 86% after a 7-year observation period. CONCLUSIONS: These results confirm the possibility of regenerating bone by means of bioabsorbable materials, assuring at the same time the long-term success for implants inserted in regenerated sites.

Absorbable Implants↗
PubMed1977

Distribution of palatal and other arteries in cleft and non-cleft human palates.

Cleft lip and cleft palate are two possible effects of fusion failure of embryonic facial processes. Aberrant facial morphogenesis suggest aberrant arterial distribution. Prompted by surgical need, studies detailing major branches of the third or pterygopalatine portion of the maxillary artery acquire practical significance. Therefore postomortem arteriographic studies were undertaken to ascertain location of these major arteries and their branches in twelve near-term human fetuses. Comparison was made between arterial distributions in three cleft and nine non-cleft fetal palates. The question of bilateral symmetry was examined. It is known that these major branches are commonly present on both sides, but the study revealed numberous variations in each facial half in both cleft and non-cleft palates. Variation implies morphologic contradiction with sterotype presentations. So numberous are the variations that occasionally they may account for sudden and unexpected hemorrhage during surgery/and retarded healing or sphacelus of flaps following surgery.

Alveolar Process↗
PubMed1999

Cellular roles in relapse processes of experimentally-moved rat molars.

This histological study was designed to clarify the relapse processes of rat molars following orthodontic tooth movement by the Waldo method. An elastic band was inserted between the upper first and second molars, and removed either 7 or 21 days later. The relapse processes of first molars were examined at 1 or 4 days after completing the 7-day-insertion and at 5 or 10 days after the end of the 21-day-insertion. At the end of the 7-day-insertion period, the mean interdental space was 158 microns, but decreased rapidly, reaching 44 microns by 1 day after removal, and 16 microns by day 4. In the periodontal ligament (PDL) compressed by elastic band insertion, partial hyalinization and/or mineralization occurred. The stretched PDL consisted of irregularly-distributed, thin principal fibres, approximately 2.4 microns in diameter. On days 1 and 4 after removal, osteoclasts, macrophage-like cells and fibroblast-like cells were localized around hyalinized tissues, but thick principal fibres, approximately 3.8 microns in diameter, were regularly distributed throughout the PDL proper. The mean interdental space after the 21-day-insertion was 536 microns, but this had decreased to 108 microns by day 5, and 71 microns by day 10. On day 5 after removal, numerous osteoclasts were evenly distributed in the compressed PDL, while thick principal fibres, approximately 3.5 microns, were present in the stretched PDL. These results suggest that, during relapse of experimentally-moved rat molars, (i) rapid remodelling of the PDL and surrounding alveolar bones is the main cause of tooth relapse and (ii) hyalinized and/or mineralized tissues occurred by compression are rapidly resorbed by osteoclasts, macrophage-like cells and fibroblast-like cells.

Alveolar Process↗
PubMed1991

Characterization of rabbit lung lysosomes and their role in surfactant dipalmitoylphosphatidylcholine catabolism.

Although alveolar surfactant is rapidly catabolized in adult rabbit lungs, the pathways have not been characterized. Pathways of surfactant secretion and recycling involve lamellar bodies and multivesicular bodies, organelles shown to be related to lysosomes by cytochemistry and autoradiography. Since lysosomes are central to intracellular catabolic events, it is possible that lysosomes are involved in intrapulmonary surfactant catabolism. Lysosomes relatively free of contaminating organelles (as determined morphologically and by marker enzymes for mitochondria, endoplasmic reticulum, peroxisomes, and plasma membranes) were obtained from post-lavage lung homogenates of 1-kg rabbits by differential centrifugation in buffered sucrose and gradient separation in percoll (density, 1.075-1.165). The role of lung lysosomes in catabolism of dipalmitoylphosphatidylcholine (DPC) was then studied in rabbits killed 4, 12, and 24 h following intratracheal injection of [3H]DPC and [14C] dihexadecyl phosphatidylcholine (DPC-ether). While equal amounts of label were in the lamellar body containing fractions at 4 h, nearly 6-fold more DPC-ether label than DPC label was recovered in the lysosomal fractions. By 24 h, there was 15-fold more DPC-ether in the lysosomes. This is the first report of successful isolation of lysosomes relatively free of other organelles from rabbit lungs. The tracer studies indicate DPC and DPC-ether follow similar intracellular processing after alveolar uptake. The subsequent accumulation of the ether analog in the lysosomal fractions supports a role for these organelles in surfactant DPC catabolism.

Animals↗
PubMed2000

Comparison of bioabsorbable and non-resorbable membranes in the treatment of dehiscence-type defects. A histomorphometric study in dogs.

BACKGROUND: The goal of this investigation was to compare, histologically and histometrically, the healing process of dehiscence-type defects treated by guided tissue regeneration (GTR) with bioabsorbable polylactic acid (PLA) membranes and non-resorbable expanded polytetrafluoroethylene (ePTF) membranes. METHODS: Six mongrel dogs were used. Buccal osseous dehiscences were surgically created on the distal roots of the mandibular third and fourth premolars. The defects were exposed to plaque accumulation for 3 months. After this period, the defects were randomly assigned to one of the treatments: GTR with bioabsorbable membrane (PLA), GTR with non-resorbable membrane (ePTFE), open flap debridement (OFD), and non-treated control (NTC). After 3 months of healing, the dogs were sacrificed and the blocks were processed. The histometric parameters evaluated included: gingival recession, epithelial length, connective tissue adaptation, new cementum, and new bone area. RESULTS: A superior length of new cementum was observed in the sites treated by GTR, regardless of the type of barrier used, in comparison with OFD (P <0.05). No statistically significant differences were found between PLA and ePTFE in any of the parameters with the exception of bone area. PLA presented a greater bone area when compared to ePTFE, OFD, and NTC (P <0.05). CONCLUSIONS: Within the limits of this study, it can be concluded that both barriers are equally effective for new cementum formation. The bioabsorbable membrane may provide a greater bone area than the non-resorbable membrane.

Absorbable Implants↗
PubMed1988

Current regenerative periodontal therapy.

Healing, after subgingival curettage, leads to the formation of a long junctional epithelium. This is a repair process and not one of regeneration. Flap procedures of themselves also seem to lead to the formation of a long junctional epithelium, notwithstanding some evidence of bone repair. Bone grafts favour osseus repair without creating new attachment, for the previous architecture and function of the tissues is not restored. Recently, use of porous hydroxyapatite implants in block or granular form has led to pocket depth reduction and attachment gain. Conditioning of the root surface, after planing, with citric acid, attachment proteins or tetracycline has been widely investigated. The use of citric acid has not led to significant periodontal regeneration but the local use of slow-release tetracycline may prove to be of value. Guided regeneration aims to re-populate the root surface with active periodontal ligament cells. In recent experiments substantial reductions in pocket depth have been achieved.

Alveolar Process↗
PubMed1990

Primary herpes simplex virus (type 1) infection delays healing of oral excisional and extraction wounds in the rat.

The effect of acute herpes simplex virus type 1 (HSV-1) infection on the healing process of intraoral wounds and tooth extraction sockets in the rat was studied. A standardized size of the buccal mucosa was excised and molars were extracted and a HSV-1 suspension was topically applied. The virus infected wounds were clinically characterized by erythema and swelling and histologically by heavy inflammation cell infiltrate and abscesses during the first week. The acute HSV-1 infection was found to significantly delay healing of both types of wounds by 3 days. Antiviral treatment with acyclovir (ACV) decreased the degree of inflammation and improved healing of the infected wounds. The present results indicate a delayed and disturbed healing of wounds in the oral cavity in the presence of HSV-1. The findings may have a clinical significance for primary or latent HSV-1 infections in conjunction with surgical intervention in the oral cavity.

Acyclovir↗
PubMed1976

Radiographic assessment of proximal infrabony pocket topography.

A method for determining the topography of interproximal infrabony pocket lesions has been presented, utilizing three intraoral radiographys. Three periapical films for the urea to be examined should be taken in a standard manner, one with the central beam angulation horizontal, another at -20degrees and the third at +20degrees. Following processing, the dried films should be examined, commencing with the -0degrees film and comparing the width of the transitional zone with that of the -20degrees film and then the film exposed with the central beam angulation at +20degrees. Following this sequence, if the transitional zone decreases in width between the 0degree and -20degrees film, then the bony destruction is greater for the buccal plate. Should the transitional zone increase in width when the above sequence of examining the film is undertaken, the bone destruction is greater for the lingual plate of bone. In each case the third film will confirm the diagnosis. In the case of horizontal bone destruction in a buccolingual direction, the transitional zone will be absent or of minimal width on the 0degree film when compared with the film exposed at +20degrees and -20degrees.

Alveolar Process↗
PubMed1995

The origin of fibroblasts and their role in the early stages of horizontal furcation defect healing in the beagle dog.

The origin of fibroblasts, their proliferative activity and roles in the early stages of periodontal repair were investigated in order to better understand the periodontal healing process in furcation defects of the beagle dog after guided tissue regenerative therapy. Newly divided cells were identified by immunolocalization of bromodeoxyuridine (BrdU) injected 1 hour prior to sacrificing the animals. At 1 and 2 weeks after creation of the defects, the lesions were occupied primarily by granulation tissue. Under this condition, periodontal ligaments (PDL) fibroblasts in a coronal portion of the remaining PDL close to wounds proliferated actively, migrated along the root surface and formed fibrous connective tissue on the surface. Similarly, the fibroblasts adjacent to the bone surface also showed proliferative activity and engaged in active formation of fibrous connective tissue on the bone surface. The majority of labeled cells in both areas were located in the extravascular area. At 3 and 4 weeks, the defects were filled with an increased amount of new connective tissue and bone. The labeled fibroblasts were preferentially found in the most coronal portion of connective tissue formed on the root surface that was in direct contact with inflamed tissue, and the collagen fibers projected into granulation tissue. In areas of active bone formation, numerous labeled fibroblasts were located in connective tissue adjacent to the newly-formed bone. However, fibroblasts in the endosteum of new bone were rarely labeled These results indicate that fibroblasts involved in periodontal repair originate primarily from both the remaining PDL and alveolar bone, and actively engage in fibrous connective tissue formation in the early stages of periodontal repair The ability of PDL fibroblasts to proliferate, migrate, and form connective tissue on the root surfaces in the early repair stages appears to play a crucial role in the formation of the PDL and cementum, and consequently, in periodontal regeneration in the absence of root resorption and ankylosis. As the formation of new connective tissue and bone continues, the precursor cells for fibroblasts and osteoblasts are supplied locally through the continued divisions of the fibroblastic cells in association with the newly-formed connective tissue. Paravascular and endosteal cells appear to be minor contributors to new cell population during furcation defect repair in the beagle dog.

Alveolar Process↗
PubMed1988

A comparison between xeroradiography and conventional radiography in the diagnosis of endodontic lesions.

Detection of periapical bone pathosis is an important part of the diagnostic process in dentistry. Xeroradiographs and E-speed films were taken to evaluate and to compare the diagnostic value for the radiographic interpretation of periapical lesions. Thirty-four patients undergoing endodontic treatment were chosen. Simultaneous exposures of the radiographic film and the xeroradiographic plates were made. The samples were viewed and categorized by the examiners using the following scores: 0 = unacceptably poor, 1 = poor but diagnostic, 2 = adequate for diagnostic information, and 3 = optimal for diagnostic information. A paired sample t test was performed on the result of the evaluation by the two examiners, and both showed that there were no significant difference at p less than 0.05 between xeroradiography and conventional radiography. A two-sample t test was performed on the means of the two examiner's evaluation, and there was no significant difference at p less than 0.05 between the means.

Alveolar Process↗