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Biomedical subjects

G M Bowers

Publications and source records attributed to G M Bowers.

At least 19 recordsLinked to original sources
PubMed2000

The treatment of intrabony defects with bone grafts.

There is substantial clinical and histological evidence that support the concept that extraoral and intraoral autogenous bone grafts and demineralized freeze-dried bone allografts are effective regenerative materials in the treatment of intrabony defects. Moreover, long-term evaluations currently available suggest that the regenerative gains achieved remain clinically stable. Synthetic grafts may result in improved probing depths and clinical attachment levels but have yet to demonstrate the ability to initiate or enhance the formation of a new attachment apparatus.

Alveolar Bone Loss↗
PubMed2000

Histology of a human biopsy section following the placement of a subepithelial connective tissue graft.

This case report histologically examines the type of attachment that can occur after root coverage of a long-standing facial recession defect on a maxillary premolar with a subepithelial connective tissue graft. Histologic findings suggest that various types of tissue attachment, including periodontal regeneration, may occur over a recession defect after placement of a subepithelial connective tissue graft. In the present case, it was noteworthy that after 1 year the greatest area of exposed root surface was covered by a connective tissue attachment (adhesion), which had remained intact during orthodontic movement and distal drifting of the tooth.

Biopsy↗
PubMed1999

Supracrestal bone regeneration: a pilot study.

The purpose of this study was to determine the feasibility of regenerating bone in patients with advanced horizontal bone loss. Demineralized freeze-dried bone allografts (DFDBA) in particle, strut, and laminar forms were used in combination with guided tissue regeneration. The cortical struts and strips were processed from long bones and were supplied in different widths and lengths. The strips were prepared in various thicknesses ranging from 100 to 500 microns; the struts ranged from 1 to 3 mm thick. These 2 materials provided structural support for the retention of DFDBA particles supracrestally, and they supported the gingival flap as a space maintainer, preventing the collapse of the tissue onto the roots and existing bone. The results indicated successful supracrestal regeneration of horizontal defects when combining existing techniques and materials. The mean attachment gain for the 7 patients studied ranged from 2.6 to 3.0 mm.

Alveolar Ridge Augmentation↗
PubMed1997

Regenerative therapy in the treatment of maxillary molar Class II furcations: case reports.

This report demonstrates the use of regenerative therapy in the treatment of maxillary molar Class II furcations. The predominant therapy provided was open debridement in combination with DFDBA, e-PTFE membranes, and citric acid root conditioning. Case reports of consecutively treated patients that include radiographs and reentry photographs demonstrate that maxillary molar furcations can be successfully treated with predictability.

Adult↗
PubMed1997

Pedicle procedure use in the management of regenerative therapy problems.

Regenerating a periodontium that has been lost because of disease has been made possible by the use of demineralized freeze-dried bone allografts (DFDBA), guided tissue regeneration with e-PTFE membranes, and combination therapies involving DFDBA covered by either an e-PTFE membrane or calcium sulfate. During regenerative therapy, problems may arise because of an adverse mucogingival condition, loss of a papilla, or significant exposure of the membrane from soft-tissue recession, slough, or fenestration leading to direct exposure of the site to the oral environment. Pedicle procedures can be used to cover these regenerative sites while providing mucogingival repair.

Adult↗
PubMed1996

Fate of demineralized freeze-dried bone allografts in human intrabony defects.

Demineralized freeze-dried bone (DFDBA) is the most widely used allograft in periodontics. Little information exists, however, on the fate of DFDBA matrix or on the effects of residual particles within grafted defects. The purpose of this study was to histologically examine the fate of DFDBA used for regeneration in intrabony defects. A secondary objective was to compare the amount of new attachment apparatus formation, including component tissues, in relation to the presence or absence of residual graft material. Histologic data were obtained from earlier studies in which intrabony defects grafted with DFDBA were removed at 6 months en bloc and submitted for histologic examination. Histologic sections (1,120) from 12 patients with 32 grafted defects revealed that 72% of the grafted defects exhibited residual DFDBA particles. When present, DFDBA appeared amalgamated within the new viable bone. Data from 5 patients with 14 grafted sites permitted a within-subject comparison of the amount of regeneration in relation to the presence or absence of residual graft material. Defects harboring residual graft particles exhibited significantly greater amounts of new attachment apparatus formation (1.72 mm vs. 0.20 mm), including new bone (2.33 mm vs. 0.23 mm), cementum (1.74 mm vs. 0.23 mm), and associated periodontal ligament than sites without evidence of graft matrix (P < or = 0.05). No apparent differences were seen in the nature of the new attachment apparatus or component tissues, other than in amount of formation. Inflammation and graft containment appear to be important factors influencing the fate of DFDBA and the regenerative response.

Alveolar Bone Loss↗
PubMed1996

Periodontal regeneration following surgical treatment.

Predictable and complete regeneration of lost periodontium remains an elusive goal, despite advances in surgical procedures and materials. Nevertheless, studies clearly demonstrate the potential for significant clinical improvements after regenerative therapy. Collectively, studies support the use of bone grafts and guided tissue regeneration (GTR) for the correction of intrabony and furcation defects. Results of several studies suggest the possibility of enhanced periodontal regeneration and enhanced stability following the use of combination techniques, such as GTR procedures with osseous grafts. Demineralized freeze-dried bone allograft (DFDBA) remains the most widely used allogeneic graft material in periodontics. Recent evidence suggests that substantial variations exist in the osteoinductive potentials of available DFDBA material. The predictability and extent of periodontal regeneration are associated with defect morphology, compliance, plaque control, inflammation, bacterial colonization, and smoking. Long-term (3- to 5-year) studies suggest that improvements following periodontal regeneration remain stable provided that patients comply with oral hygiene regimens and regular supportive periodontal treatment.

Alveolar Bone Loss↗
PubMed1996

Modifications of the subpedicle connective tissue graft technique: a predictable procedure for covering exposed roots.

This article reviews modifications to Nelson's technique for covering exposed roots using an autogenous connective tissue graft covered by a double papilla pedicle graft. Case reports will illustrate how this technique can be used for both root surfaces pathologically exposed to the oral environment and those previously restored with cosmetic bonding procedures. Enhancements of this procedure over Nelson's original description will be enumerated, and advantages over other root coverage modalities will be presented.

Adult↗
PubMed1995

Periodontal regeneration of intrabony defects: an evidence-based treatment approach.

A task force of periodontists established clinical and histologic outcomes (goals) for the treatment of intrabony defects and researched the literature for techniques that would most predictably achieve these goals. The group also identified factors that could influence predictability. The treatment outcomes selected by the task force included regeneration of a true attachment apparatus; gain in bone and probing attachment levels; reduction in probing pocket depth; minimal gingival recession; increased patient comfort; esthetic appearance and state of wellness; and maintenance of health, comfort, and function over time. Based on evidence, it was concluded that guided tissue regeneration, guided tissue regeneration combined with the use of decalcified freeze dried bone allografts and freeze-dried bone allografts alone are the most predictable regenerative procedures for achieving selected treatment outcomes. Various factors, such as patient characteristics, the morphology of the defect, and the surgical technique can influence the healing response of intrabony defects. Patient factors, such as plaque control, compliance, and cigarette smoking, can directly affect predictability of periodontal regeneration. Defect selection is critical, and deep and narrow defects are the most predictable response to regenerative procedures. The number of remaining bony walls is important in grafting procedures, but their influence is questionable in guided tissue regeneration. Various technical procedures, such as flap design, defect debridement, and wound protection, may influence the predictability of regeneration.

Alveolar Bone Loss↗
PubMed1995

Correction of a large periradicular lesion and mucosal defect using combined endodontic and periodontal therapy: a case report.

The successful treatment of a large endodontically induced periradicular defect and soft tissue fenestration by combined endodontic and periodontal therapy is described. Endodontics was performed on the mandibular left central incisor, the apex was resected, and a retrograde amalgam was placed. The defect was thoroughly debrided and the exposed root surface was planed with curettes. Demineralized freeze-dried bone allograft and a nonresorbable membrane were placed over the defect and the exposed root surface. The membrane was removed in 6 months and there appeared to be bone regeneration with complete closure of the soft tissue fenestration. Endodontic therapy in combination with guided tissue regeneration and bone grafting may provide another modality of treatment for endodontically related hard and soft tissue defects.

Alveolar Bone Loss↗
PubMed1990

Regenerating bone in clinical periodontics.

Bone autografts and allografts, various alloplastic materials, and guided tissue regeneration are used to reconstruct lost periodontal tissues. This paper focuses on controversies related to these therapeutic modalities as well as their role in periodontal regeneration.

Alveolar Bone Loss↗
PubMed1990

The apical location of calculus within the intrabony defect.

Although several studies have concluded that calculus removal becomes more difficult as pocket depth increases, few have examined the clinical location of calculus within the intrabony defect. This study evaluated the relationship between apical calculus position and the depth and morphology of the intrabony defect. As part of an on-going study of new attachment procedures in humans, 260 intrabony defects were surgically entered in 39 patients. Using magnifying loops and fiber optics in all defects, the most apical level of calculus was grooved to serve as both a clinical and histologic reference point. Clinical measurements made prior to root debridement included the alveolar crest to base of calculus, and the base of calculus to base of defect. The type of defect was classified by the number of remaining osseous walls. Calculus has not been found apical to the groove in any histologic section. The mean distance measured clinically between the base of the calculus and the base of the defect was found to increase with the depth of the defect. This relationship did not vary with either tooth type or number of remaining osseous walls in the defect. Data analysis of this group of patients (N = 39) showed a positive correlation (r = .83) between increasing depth of intrabony defect and the distance of the most apical calculus from the defect base.

Alveolar Process↗
PubMed1989

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.

Analysis of Variance↗
PubMed1989

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.

Alveolar Process↗
PubMed1989

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

There is still controversy as to the role of bone grafting materials in the formation of a new attachment apparatus and component tissues (bone, cementum, and periodontal ligament). The purpose of this study was to compare the healing of intrabony defects with and without the placement of decalcified freeze-dried bone allograft (DFDBA) in a nonsubmerged environment in humans. The most apical level of calculus on the root served as a histologic reference point to delineate root surfaces exposed to the oral environment and to measure new attachment apparatus and new component tissue formation. Free gingival grafts were placed over grafted and nongrafted defects to retard epithelial migration. Biopsies were obtained at 6 months and regeneration was evaluated histometrically. Data from 12 patients with 32 grafted and 25 nongrafted defects were submitted for statistical analysis. Results indicate that in nongrafted defects, a long junctional epithelium formed along the entire length of exposed root surfaces and often extended apical to the calculus reference notch. Free gingival grafts did not enhance regeneration of a new attachment apparatus, new cementum, new connective tissue, or new bone in nongrafted defects. The formation of a new attachment apparatus was observed when intrabony defects were grafted with DFDBA (x1.21 mm); significantly more new attachment apparatus (P less than .005), new cementum (P less than .005), new connective tissue (P less than .05), and new bone (P less than .0001) formed in intrabony defects grafted with DFDBA than in nongrafted defects. There was a greater chance for regeneration of a new attachment apparatus and component tissues in grafted defects than in nongrafted defects. New cellular cementum formed on old cementum and dentin but more often formed over both in the same defect). The periodontal ligament was more frequently oriented perpendicular to the root; there was greater loss in alveolar crest height in nongrafted than grafted defects (P less than .05); and extensive root resorption, ankylosis, and pulp death were not observed in grafted or nongrafted defects.

Analysis of Variance↗