Histologic evaluation of new attachment in human intrabony defects. A literature review

Fibrin and fibronectin sealing system in a guided tissue regeneration procedure. A case report

A case is reported showing an iatrogenic, chronic abscess of six years' duration associated with a bony defect between the maxillary right central and lateral incisors. The osseous defect was treated by a guided tissue regeneration procedure with the use of a fibrin and fibronectin sealing system. The system was employed to fix the membranes and keep them apart from the root surface, thereby maintaining room for bone regeneration. This operation resulted in a 9-mm clinical attachment gain and in an 11-mm filling of the osseous defect. The second surgical stage after a three-month reentry procedure was strictly for cosmetic improvement by means of a free gingival graft.

Calcium phosphate materials in restorative dentistry: a review

This report deals with some of the calcium phosphate materials which are currently used in preventive and restorative dentistry and other calcium phosphate materials which have potential for dental and medical applications. Such materials include those which form calcium phosphate in situ (e.g., Bioglass ceramics and calcium phosphate cements) and those originating from natural materials (such as corals and bones).

The reports on the development and current status of the calcium phosphate ceramics and glass ceramics presented here were based on recent reviews and recent evaluations of clinical studies for the period 1975 to 1986 (Table 3) with humans and with animals when reports on human studies were not yet available. Methods of preparation and relevant physico-chemical properties of some of the calcium phosphate materials were based on data reported in the literature and on other studies by the author. New calcium phosphate materials, e.g., calcium phosphate cements, calcium phosphate-coated implants, calcium phosphate/polymer composites, have also been briefly covered in this report.

Based on the information summarized in Tables 1 to 6 and on solicited comments from clinicians and researchers involved with calcium phosphate materials, several areas of basic and clinical research are recommended (Table 7).

Treatment of intraosseous periodontal defects with a combined adjunctive therapy of citric acid conditioning, bone grafting, and placement of collagenous membranes

A total of 25 proximal, intraosseous periodontal defects were treated in 21 adult patients. A 3-prong adjunctive, regenerative treatment approach was used. The treatment included (1) citric acid conditioning of the root surfaces, (2) grafting of particles of decalcified, freeze-dried homologous bone, and (3) placement of freeze-dried, homologous dura mater sheets between the replaced surgical flaps and the tooth surfaces. The results, as evaluated by probing attachment and probing bone level measurements, during 1 year of observation, demonstrated limited improvements of the treated defects. The limited results were similar to previous observations in our clinics following treatment of intraosseous defects using different treatment modalities. It appears that new treatment approaches need to be sought to accomplish clinically significant and predictable regeneration in proximal, intraosseous periodontal defects.

Treatment of periodontal furcation defects. (II). Bone regeneration in mandibular class II defects

A total of 30 mandibular, buccal class II furcation defects were treated in 22 subjects using a regenerative surgical therapy that included citric acid root conditioning and coronally positioned flaps secured by crown-attached sutures. In addition, grafts of freeze-dried, decalcified allogenic bone were placed in 16 of the 30 defects. The effect of the therapies was evaluated from a series of soft and hard tissue measurements. These measurements demonstrated notable improvement 12 months following therapy. On the average, 67% of the defect volume became filled with bone. 43% of treated defects were completely closed by bone fill. No difference was observed between defects treated with and without bone grafts.

A comparative study of human periodontal ligament cells and gingival fibroblasts in vitro

Both periodontal ligament and gingival tissue are thought to harbor cells with the ability to stimulate periodontal regeneration, i.e., formation of new bone, cementum, and connective tissue attachment. To understand further the role of these cells in the regenerative process, we compared human periodontal ligament cells and gingival fibroblasts, both derived from the same patient, same passage, in vitro. Protein and collagen production was significantly greater in periodontal ligament cells when compared with that of gingival fibroblasts. In addition, periodontal ligament cells had higher alkaline phosphatase levels when compared with those of gingival fibroblasts.

Transplantation of mandibular third molar in seventh decade: long-term follow-up and evaluation

Transplantation of a nonfunctional mandibular third molar into the opposite mandibular second molar site, where it was necessary to remove the second molar of a 61-year-old patient, has been reported. There was long-term follow-up and evaluation, with radiographs and clinical examination during the ninth postoperative year. The patient had no complaints related to the transplant at the long-term follow-up visit. The periodontal tissues were in excellent condition. The tooth was firm, and the radiograph demonstrated growth of new attachment by showing lamina dura and periodontal ligament space. There was filling-in of bone in the lateral and periapical areas, and there was no evidence of resorption. A root canal filling had been acquired in the transplant between the second and ninth postoperative years.

Histologic and clinical responses to porous hydroxylapatite implants in human periodontal defects. Three to twelve months postimplantation

Twelve intrabony periodontal lesions in three volunteers received surgical debridement followed by site implantation of porous hydroxylapatite implants. These patients were followed over a total of a 1-year observation period. Blocks of treated sites were surgically removed at 3 months, 6 months and 12 months after implantation. Clinical observation indicated a reduction in pocket depth consisting of both recession and clinical gain of attachment. No ill effects were observed. Histologic examination of the treated sites showed ossification of the implant pores and the implant periphery as early as 3 months after implantation, which became pronounced 12 months after placement. At times, peripheral ossification linked with crestal osseous seams. This ossification occurred in the presence of an adjacent root covering, long junctional epithelium, and thus there was no new attachment. On the other hand, this graft material offers the potential of increasing new bone mass within a human intrabony lesion.

Mechanism of fibroblast attachment to bone extracellular matrix: role of a 44 kilodalton bone phosphoprotein

While the exact mechanisms regulating bone homeostasis are unknown, it is generally accepted that factors with the capacity to regulate cell attachment and spreading play a role in osteogenesis. A 44 kDa bone phosphoprotein (44K BPP), isolated from rat bone and synthesized by osteoblasts, was evaluated for its role in attachment and spreading of fibroblasts. In uncoated plates, enhanced cell attachment and spreading were observed when fibroblasts were exposed to the 44K BPP. The attachment properties of the bone phosphoprotein are different from those of fibronectin, in that the 44K BPP did not promote cell attachment in type I collagen wells, as was seen with fibronectin. Also, 44K BPP continued to enhance cell attachment up to 24 h, whereas cell attachment declined in time with cells exposed to fibronectin. Cycloheximide did not alter 44K BPP promotion of cell attachment, indicating that de novo protein synthesis was not required. These studies suggest that the 44K BPP is important in the regulation of cell attachment and spreading at sites of mineralization.

Enhancement by extracts of mineralized tissues of protein production by human gingival fibroblasts in vitro

Non-confluent cell cultures were exposed to both guanidine and guanidine-EDTA extracts of cementum, dentine and alveolar bone, at concentrations from 2 to 50 micrograms/ml for 48 h. The cells were radioactively labelled during the last 24 h. Total protein production was measured via incorporation of radioactive proline; collagen production was estimated by digestion of the radioactive protein mixture with bacterial collagenase. All guanidine-EDTA extracts elicited statistically-significant increases in total protein production when compared to controls. At 50 micrograms/ml of extract, the increase in protein production was 340, 143 and 338 per cent for bone, cementum and dentine, respectively. Similar results were obtained for collagen production. Guanidine-EDTA extracts also stimulated an increase in the production of specific proteins, as ascertained by gel electrophoresis. In contrast, the guanidine extracts had no effect on either protein or collagen production. Thus the functions of gingival fibroblasts can be altered by proteins from associated mineralized tissues. Identification of such proteins and their biological functions would enhance knowledge of the mechanisms that regulate connective-tissue regeneration.

Histological evaluation of human intraosseous healing responses to the placement of tricalcium phosphate ceramic implants. I. Three to eight months

Eight intrabony lesions in four patients were removed en bloc 3 to 8 months after periodontal flap debridement. At the time of debridement, the position of the gingival margin and the most apically located calculus were notched to serve as reference points. All lesions received "Synthograft" implants and lesions healed uneventfully. Even though these were severely involved periodontal sites, clinical measurements at time of block removal demonstrated gingival recession (average = 2.9 mm) and a gain in clinical closure (average = 2.6 mm). Histologically, graft particles were present in each specimen. They were walled off by collagen and did not appear to enhance new attachment nor did they induce an inflammatory infiltrate. Thus, they seemed to act as nonirritating fillers. Microscopically, closure of the lesions demonstrated repair with limited evidence of new connective tissue attachment. Histologic expression of the clinical gain in closure was the result of closure by long epithelial adhesion (long junctional epithelium) and possible linkage of dentinal collagen with gingival fibers at areas of dentinal resorption. These variations in closure were often seen within the same clinical site.

Healing responses to grafting of combined collagen-decalcified bone in periodontal defects in dogs

The feasibility of a new combined collagen gel-autolysed antigen-extracted allogeneic bone implant was tested. Its effect on gaining new attachment in surgically created defects in four dogs was evaluated over 24 weeks. As controls, sites receiving implants of the bone implant alone, nonimplanted and untreated defects were also evaluated. The collagen gel encouraged ingrowth of regenerative tissue-fibroblasts in the early stages of wound healing while the allogeneic bone induced new bone formation. The graft materials were bicompatible, technically manageable and clinically effective. From the present preliminary study, it was evident that the combined autolysed antigen-extracted allogeneic bone-collagen gel implant may offer advantages over the present implant materials and techniques currently used in the treatment of periodontal intrabony defects.

Speculations on periodontal attachment loss

A hypothesis is presented depicting patterns of human periodontal attachment loss. The patterns described occur rapidly, are site-specific and take place in response to virulence and duration of local irritants. They appear to mirror current clinical observations regarding the nature and progress of site-specific periodontal lesions.

Healing of horizontal circumferential periodontal defects following regenerative surgery in beagle dogs

Regenerative surgery of dog teeth with reduced periodontal support was undertaken to determine: if new connective tissue attachment could be predictably attained back to the level of the cemento-enamel junction; and to what extent the new attachment would be accompanied by bone regeneration, root resorption, and ankylosis. The alveolar bone around mandibular premolars was surgically reduced up to 6 mm from the cementoenamel junction. The denuded root surfaces were exposed to the oral environment during a period of 3 months without plaque control. Regenerative surgery was then carried out employing citric acid root conditioning and coronally positioned flaps. 6 months later, histologic evaluation of the midbuccal and midlingual areas of mesial and distal roots revealed new attachment over extended portions of the root surfaces. In 91 of 120 available surfaces, there was no epithelial downgrowth apical to the cemento-enamel junction. Bone regeneration varied from negligible amounts to complete reformation. However, root resorption and ankylosis were prevalent features. 2 different types of resorptions could be distinguished: those occurring near the cemento-enamel junction (cervical resorption), and those occurring more apically in areas of newly formed bone (ankylosis-associated resorption). Resorption of either or both types was noted for 92 of the 120 surfaces.

Healing after treatment of periodontal intraosseous defects. V. Effect of root planing versus flap surgery

The present study compared surgical therapy to root planing alone in the treatment of periodontal intraosseous defects. 25 defects in 14 patients were subjected to root planing only and another 25 defects in the same patients were surgically exposed and citric acid treated. The healing response was evaluated 6 months after treatment. The mean gain of probing attachment level was 0.8 mm in the root-planed defects as compared to 1.3 mm for the surgically exposed and acid-treated defects. The probing bone level improved an average of 0.2 mm for the root-planed areas as compared to 0.6 mm for the acid-treated defects. The mean preoperative probing pocket depths of 6.7 mm and 6.8 mm for the 2 groups were reduced to 5.2 mm and 4.1 mm, respectively. The differences in these parameters were statistically significant between the 2 groups. However, both groups demonstrated limited regeneration.

Evaluation of durapatite ceramic as an alloplastic implant in periodontal osseous defects. II. Twelve month reentry results

Thirteen patients received Durapatite, a hydroxylapatite ceramic (Periograf), as a bone implant material in various types of intrabony defects following internally beveled full thickness flaps, root planing, and defect debridement. All osseous margins and defects were measured from the cemento-enamel junction (CEJ) at specific locations using a standardized periodontal probe. Similarly debrided, nonimplanted defects served as controls. Defect selection as either experimental or control site was based on an alternating defects design after local therapy was completed. Periodontal dressing and systemic tetracycline were used for 10 days. Postsurgical visits for documentation and plaque control were at 10, 20 and 30 days, and 3, 6, 9 and 12 months. Measurements relating to defect changes were made at the 12-month surgical reentry. For evaluation purposes original defect depths were divided into three groups. In Group I (less than 3 mm) defect fill was 1.0 mm (47%) for the implanted defects and 0.3 mm (33%) for the control sites (significantly different at P less than 0.05). In Group II (3-6 mm) defect fill of 1.7 mm (44%) for implanted sites was significantly better (P less than 0.05) than the 0.8 mm (29%) found in control sites. In the deepest group (Group III, greater than 6 mm) Durapatite placement yielded 2.1 mm (32%) of defect fill while debridement alone resulted in 1.8 mm (26%) of fill (P greater than 0.05). Hard tissue responses demonstrated a substantial advantage for use of Durapatite over controls, while soft tissue changes were similar for both.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of implants on healing of experimental furcation defects in dogs

The present study was performed to find out whether implants placed around periodontally involved teeth during reconstructive surgery would support replaced flaps and prolong gingival coverage of the treated root surfaces facilitating new attachment. Through-and-through furcation defects were made in the mandibular second, third, and fourth premolars of 10 beagle dogs. Bone was surgically removed from the furcation and from the circumference of each tooth to a level 3 to 4 mm apical to the cementoenamel junction. Steel wires were passed through the furcations and ligated to enhance plaque formation. At 6 weeks, the wires were removed. At 12 weeks, during reconstructive surgery, 4 dogs received implants of autogenous intraoral cancellous bone, 2 of autogenous iliac cancellous bone and marrow, 2 of Proplast, and 2 of Avitene. The results demonstrated that none of 12 teeth implanted with Avitene or Proplast showed new attachment. Only 2 of 6 teeth implanted with autogenous iliac bone showed new attachment, combined with extensive root resorption and ankylosis. Of 12 teeth implanted with autogenous intraoral bone, 6 showed new attachment. Our findings suggest that flap support by intraoral cancellous bone implants may facilitate new attachment. A more predictable technique, however, needs to be developed.

An evaluation of tricalcium phosphate implants in human periodontal osseous defects of two patients

This study evaluated the use of tricalcium phosphate (TCP) ceramic implant material in periodontal osseous defects. Thirteen defects in two patients were treated with mucoperiosteal flaps and placement of TCP. The defects were evaluated clinically and radiographically utilizing standardized probe placement and radiographic technique. Clinically, there was a mean probing pocket reduction of 4.5 mm as a result of a mean gain of clinical probing attachment level of 2.0 mm and a mean gingival recession of 2.5 mm. Radiographically, there was a mean "fill" of 1.8 mm. Six teeth were removed by block biopsy for histologic analysis, three at 3 months, one at 6 months and two a 9 months. The TCP particles were well tolerated and encapsulated by fibrous connective tissue, but the particles did not stimulate new bone growth. The junctional epithelium ended 1.62 mm coronal to the apical extent of a reference notch placed at the base of the defect. Although new cementum was observed, there was limited evidence of new attachment.

Histological assessment of human periodontal defect after durapatite ceramic implant. Report of a case

Durapatite particles were employed along with autogenous bone chips to treat an extensive periodontal defect on a mandibular first molar which involved the bifurcation area and the distal root. Nine weeks after treatment the tooth was found to be cracked and was extracted along with tissue containing the grafted sites. The histologic specimen demonstrated that the ceramic graft particles were compatible with the periodontal tissues and showed no evidence of rejection or extrusion. They appeared completely encapsulated by connective tissue fibers while active osteogenesis was noted on the bone fragments implanted with them. Cementogenesis and connective tissue attachment to the root were seen adjacent to the durapatite particles. This healing was believed to be related to the earlier surgical denudation of this portion of the root during treatment and was unrelated to the placement of the graft.