Histologic evaluation of new attachment apparatus formation in humans. Part I

Part I of this three-part human study evaluated the formation of a new attachment apparatus (bone, cementum, and periodontal ligament) on pathologically exposed root surfaces in an open and closed environment. The most apical level of calculus on the root served as a histologic reference point to measure regeneration on root surfaces exposed to the oral environment. Attempts were made to initiate the formation of a new attachment apparatus by flap curettage, root planing, coronectomy, and submersion of vital roots beneath the mucosa. Nonsubmerged defects were treated by the same surgical technique and served as controls. Biopsies were obtained at 6 months and regeneration was evaluated histometrically by two investigators who were unaware of the treatment performed. Data from 9 patients with 25 submerged and 22 nonsubmerged defects were submitted for statistical analysis. Results indicate that a new attachment apparatus did not form in any of the 22 nonsubmerged teeth; a new attachment apparatus did form in a submerged environment (0.75 mm); significantly more new attachment apparatus (P less than 0.05), new cementum (P less than 0.01), new connective tissue (P less than 0.05), and new bone (P less than 0.02) formed in submerged defects; new cementum was cellular in nature and formed equally well on old cementum and dentin. Greater percent positive regeneration of the attachment apparatus and all component tissues occurred in submerged defects and no extensive root resorption, ankylosis, or pulp death was observed on submerged or nonsubmerged roots.     

Histologic evaluation of new attachment apparatus formation in humans. Part II

There is conflicting evidence regarding the value of graft materials in enhancing the formation of new bone, cementum, and periodontal ligament (new attachment apparatus). Part II of this study compared the healing of intrabony defects with and without the placement of decalcified freeze-dried bone allograft (DFDBA) in a submerged environment. The most apical level of calculus on the root served as a histologic reference point to measure regeneration on root surfaces exposed to the oral environment. Biopsies were obtained at 6-months and evaluated histometrically by two investigators unaware of the treatment performed. Data from 9 patients with 30 grafted defects and 13 nongrafted defects were submitted for statistical analysis. Results indicate that in a submerged environment significantly more new attachment apparatus (P less than .05) and new bone (P less than .05) formed in grafted than nongrafted sites. Significantly greater loss of alveolar crest height occurred in nongrafted than grafted defects (P less than .05); regeneration of new attachment apparatus, new bone, and new cementum occurred more frequently in grafted than nongrafted defects. There was a greater chance for the regeneration of a connective tissue attachment in nongrafted intrabony defects than in grafted defects; new cellular cementum formed equally well on old cementum, dentin, or both old cementum and dentin in the same defect. The periodontal ligament was oriented parallel, perpendicular, or both parallel and perpendicular in the same defect; and, no extensive root resorption, ankylosis, or pulp death was observed in grafted or nongrafted defects.     

Histologic evaluation of new attachment in humans. A preliminary report

This study was designed to evaluate the potential for regeneration of a new attachment (alveolar bone, cementum and a functional periodontal ligament) in patients whose attachment apparatus had been destroyed by periodontal disease. In each of the three parts of the investigation, the most apical level of calculus on the root served as a histologic reference point to measure regeneration. In Part I, attempts were made to initiate the formation of a new attachment by surgical debridement, crown removal (coronectomy) and submersion of the vital root below the mucosa. Nonsubmerged, surgically debrided defects served as controls. In Part II, debrided intrabony defects were treated with and without demineralized freeze-dried bone allograft and the associated vital roots were submerged. Part III evaluated potential for regeneration of a new attachment in nonsubmerged roots with and without the use of demineralized freeze-dried bone allograft. Gingival grafts were placed over the experimental and control sites in an attempt to retard epithelial migration. Biopsies were obtained in 6 months and regeneration was evaluated histometrically. Preliminary results in 7 patients and 24 intrabony defects indicate that new attachment is possible on pathologically exposed root surfaces in a submerged environment with and without the incorporation of demineralized freeze-dried bone allografts. New attachment was observed on pathologically exposed root surfaces in a nonsubmerged environment when intrabony defects were grafted with demineralized freeze-dried bone allograft. New attachment was not observed on nongrafted, nonsubmerged, defects with and without the placement of gingival grafts over the defects.     

Histologic evaluation of an Nd:YAG laser-assisted new attachment procedure in humans

This report presents histologic results in humans following a laser-assisted new attachment procedure (LANAP) for the treatment of periodontal pockets. Six pairs of single-rooted teeth with moderate to advanced chronic periodontitis associated with subgingival calculus deposits were treated. A bur notch was placed within the pocket at the clinically and radiographically measured apical extent of calculus. All teeth were scaled and root planed with ultrasonic and hand scalers. One of each pair of teeth received treatment of the inner pocket wall with a free-running pulsed neodymium:yttrium-aluminum-garnet (Nd:YAG) laser to remove the pocket epithelium, and the test pockets were lased a second time to seal the pocket. After 3 months, all treated teeth were removed en bloc for histologic processing. LANAP-treated teeth exhibited greater probing depth reductions and clinical probing attachment level gains than the control teeth. All LANAP-treated specimens showed new cementum and new connective tissue attachment in and occasionally coronal to the notch, whereas five of the six control teeth had a long junctional epithelium with no evidence of new attachment or regeneration. There was no evidence of any adverse histologic changes around the LANAP specimens. These cases support the concept that LANAP can be associated with cementum-mediated new connective tissue attachment and apparent periodontal regeneration of diseased root surfaces in humans.     

Longitudinal evaluation of the excisional new attachment procedure in humans.

Evaluation of the Excisional New Attachment Procedure (ENAP) was extended to 3 years postoperatively. Generally, there was an overall mean increase in sulcus depth of 0.5 mm; an overall mean increase in recession of 0.1 mm; and an overall mean decrease in the amount of previously gained new attachment of 0.6 mm between 1 year and 3 years after surgery. These values reflected a statistically significant, but clinically insignificant, difference in mean sulcus depth and mean attachment level between the two evaluation periods. Only one tooth site demonstrated clinical findings worse than those determined preoperatively. These results are similar to those of other longitudinal studies.     

Histologic evaluation of connective tissue grafts in humans

The goal of this study was to evaluate the histologic composition of connective tissue grafts removed from the area palatal of the first molar through the premolars. In spite of attempts to remove the epithelium, it remained in 24 of 30 grafts (80%). The incisal portion of the connective tissue graft was comprised of lamina propria. The mean depth of the lamina propria was 3.2 mm (65.2% of the graft). Apical to the lamina propria was the submucosa, which was primarily composed of adipose tissue. The mean depth of the submucosa was 2.0 mm (34.8% of the graft). There was no statistically significant difference in the composition of the grafts based on smoking or age. The grafts were successful in producing root coverage. There were 27 patients with Class I or II recession defects in this study; this group had a mean root coverage of 97.9%. This study demonstrated that most connective tissue grafts are not uniform in composition and quite often contain some epithelium. However, all of the grafts were clinically usable and produced a clinically successful result.     

An evaluation of new attachment formation using a microfibrillar collagen barrier

The objective of this study was to evaluate the effectiveness of microfibrillar collagen as a barrier to prevent epithelial migration and allow for guided tissue regeneration. Fourteen study teeth were selected. Mucoperiosteal flaps were elevated and roots were debrided and planed. Avitene was placed over teeth and alveolar bone. Flaps were then sutured over it. At control sites no Avitene was placed. At 90 days, block sections were obtained and processed for histologic and histometric evaluation. Results revealed that all specimens had a long junctional epithelial attachment. New attachment was present within the area of the root notch at the original level of the alveolar bone, and there was no significant difference in mean connective tissue attachment between the control and experimental specimens (P = 0.614). Avitene did not form an effective barrier to epithelial migration nor did it allow for guided tissue regeneration and significant new attachment formation in humans.     

Mechanisms of new attachment formation

Abstract A goal of periodontal therapy is predictable regeneration of a periodontium at the site of a previous marginal periodontitis. Current clinical therapeutic techniques result in repair, and not regeneration with formation of a new connective-tissue attachment. Investigations have shown that surface demineralization of dentin predisposes toward a new connective-tissue attachment, and this attachment may take place in an environment lacking periodontal progenitor cell populations. The role of the root surface is considered regarding inhibition and facilitation of these connective tissue responses.     

Histologic evaluation of guided vertical ridge augmentation around implants in humans

Recent experimental and clinical case reports demonstrated vertical ridge regeneration in atrophic posterior mandibles and maxillae. Although the results from these clinical cases are quite encouraging there is a lack of human histologic data on the newly regenerated tissue around commercially available titanium implants. The aim of the present study was to perform a qualitative and quantitative histologic analysis of the bone response to previously exposed implant threads after treatment with guided bone regeneration in a series of patients. A total of 30 Nobel Biocare implants were consecutively placed in 6 patients with partially edentulous mandibles. Of these implants, 6 were planned for removal after 1 year, whereas the remaining 24 implants were inserted to function as support for a fixed partial denture. The 6 experimental implants were intentionally allowed to protrude occlusally 5 to 7 mm from the bone crest without counter-sinking. The exposed implant threads were completely covered by autogenous bone chips. After a 12-month healing period the 6 experimental implants were removed with trephine burs. Bone-to-metal contact and bone density in the implant threads were measured. Clinically, all implants were stable and there was complete tissue fill of the space underneath the membranes. Histologically, a substantial amount of new bone had formed underneath the membrane in all cases. Histomorphometrically, there was a lower bone-to-metal contact percentage in the exposed compared to the nonexposed region in every case. With respect to bone density, there was a mean of 43.2% in previously exposed regions compared to 60.3% in previously nonexposed regions.     

Hematology and dentistry. Part III. Fibrin formation disorder

After the formation of a platelet-plug, generation of fibrin is necessary for its stabilization. Both congenital and acquired deficiencies of clotting factors occur, leading to retarded formation of fibrin. In congenital disorders, preoperative correction is possible and necessary. In acquired deficiencies, the type and feasibility of correction depends on the cause of the deficiency.     

Histologic evaluation of three methods of periodontal root surface treatment in humans

BACKGROUND: Removing subgingival plaque and calculus is a major goal of periodontal treatment. Few attempts have been made to evaluate the use of lasers for root surface debridement in periodontal therapy. The aim of the present study was to compare, histologically, the effects of hand instrumentation, ultrasonic instrumentation, and CO2 lasers on the root surfaces of teeth treated in situ. METHODS: A total of 33 teeth scheduled for extraction due to severe periodontal disease were divided into three groups. In the first group, teeth were treated by ultrasonic bactericidal curettage (UBC) with an ultrasonic scaler; in the second group, teeth were treated by hand instrumentation; and in the third group, after hand instrumentation, roots were lased by a CO2 laser. The samples were then processed for histological examination. RESULTS: In the first and second groups, plaque and calculus were present in interradicular septa, lacunae, and surface concavities. In the third group, surfaces of specimens treated by a low-power defocused CO2 laser showed areas devoid of cementum, with completely sealed dentinal tubules, and no bacterial cell remnants. CONCLUSIONS: The CO2 laser treatment, used at low power and in the defocused mode, combined with traditional mechanical instrumentation, could improve root surface debridement of periodontally involved teeth. More extensive, long-term studies are needed to confirm this hypothesis.     

A clinical study of healing in humans following the excisional new attachment procedure.

The excisional new attachment procedure was used to treat 75 suprabony pockets on 32 teeth in 9 patients. One-year postoperative measurements demonstrated an overall mean pocket reduction from 4.7 mm to 2.0 mm, of which 2.1 mm (77%) was new attachment and 0.6 mm was recession. Average amount of new attachment and percentage of new attachment were greatest on the midlingual surfaces of the teeth treated in this study. The results of this study showed the excisional new attachment procedure to be a simple, effective, and predictable procedure for achieving pocket elimination by means of a clinical new attachment of the gingival tissues in suprabony pockets.     

Histologic evaluation of autogenous connective tissue and acellular dermal matrix grafts in humans

BACKGROUND: The clinical success of root coverage with autogenous connective tissue (CT) or acellular dermal matrix (ADM) has been well documented. However, limited histological results of CT grafts have been reported, and a case report of a human block section has been published documenting an ADM graft. The purpose of this study is to document the histological results of CT grafts, ADM grafts, and coronally advanced flaps to cover denuded roots in humans. METHODS: This study included four patients previously treatment planned for extractions of three or more anterior teeth. Three teeth in each patient were selected and randomly designated to receive either a CT or ADM graft beneath a coronally advanced flap (tests) or coronally advanced flap alone (control). Six months postoperatively block section extractions were performed and the teeth processed for histologic evaluation with hematoxylin-eosin and Verhoeff's stains. RESULTS: Histologically, both the CT and ADM were well incorporated within the recipient tissues. New fibroblasts, vascular elements, and collagen were present throughout the ADM, while retention of the transplanted elastic fibers was apparent. No effect on the keratinization or connective tissue organization of the overlying alveolar mucosa was evident with either graft. For both materials, areas of cemental deposition were present within the root notches, the alveolar bone was essentially unaffected, and the attachments to the root surfaces were similar. CONCLUSION: Although CT and ADM have a slightly different histological appearance, both can successfully be used to cover denuded roots with similar attachments and no adverse healing.     

Histologic evaluation of root coverage obtained with GTR in humans: a case report

The purpose of this study was to histologically evaluate four teeth with recession defects that were treated with guided tissue regeneration (GTR). The amount of root coverage obtained ranged from 16.7% to 50.0%. In one of the defects treated, new bone was formed but none of the new bone was coronal to the original gingival margin. Additionally, in this one case new cementum and connective tissue attachment was formed. However, because the new bone, new cementum, and new connective tissue were not coronal to the original gingival margin, this result could not be classified as regeneration. The vast majority of the attachment in this defect was long junctional epithelial attachment in the portion of the recession defect covered by the root-coverage procedure. In the other three defects treated, there was a loss of bone. All of the root coverage obtained was a long junctional epithelial attachment in three of the four defects. The results of this study do not show regeneration in any of the four defects treated.