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Biomedical subjects

R A Yukna

Publications and source records attributed to R A Yukna.

At least 19 recordsLinked to original sources
PubMed1992

Human gingival tissue response to HTR polymer.

Biopsies secured during reentry surgical evaluation of previously treated periodontal osseous defects were examined for gingival tissue response to HTR polymer. Eleven patients provided biopsies of HTR grafted sites 6-7 months after initial implantation. Minimal inflammation and infrequent foreign body giant cells were found. Bone was present in about half of the samples and osteogenesis associated with the HTR graft material was seen in about 20% of the biopsies. Serendipitously, biopsies of other graft materials or debridement only sites from 6-30 months post-treatment were also available for analysis and comparison, and showed similar tissue response. The results of this study suggest that HTR polymer (and other graft materials) is very biocompatible and elicits no untoward gingival tissue responses when placed in periodontal osseous defects.

Adult↗
PubMed1992

Clinical human comparison of expanded polytetrafluoroethylene barrier membrane and freeze-dried dura mater allografts for guided tissue regeneration of lost periodontal support. I. Mandibular molar Class II furcations.

The response of mandibular Class II facial furcations to guided tissue regeneration treatment with expanded polytetrafluoroethylene barrier membrane (e-PTFE) or freeze-dried dura mater allograft (FDDMA) barriers was evaluated in 11 pairs of molars in 11 patients. Following initial preparation, full thickness flaps were raised in the area being treated, the bone and furcation defects debrided of granulomatous tissue, and the involved root surfaces mechanically and chemically prepared. By random allocation, e-PTFE or FDDMA barriers were fitted over the furcations, secured in place, and the host flap repositioned or coronally positioned. Postsurgical deplaquing was performed every 10 days leading up to e-PTFE removal at about 6 weeks (the resorbable FDDMA did not require removal). Continuing supportive periodontal therapy was provided until surgical re-entry at one year for documentation and any further necessary treatment. Direct clinical measurements demonstrated essentially similar clinical results with both barrier materials for bone and soft tissue changes (few statistically or clinically significant differences). Exceptions were the amount of horizontal furcation fill and the change in the width of the keratinized gingiva, both of which were better with FDDMA (P less than 0.05). Improvements in open probing attachment levels observed at the time of e-PTFE removal were lost over the intervening months, more so for the vertical than the horizontal component of the furcation lesion. Intrapatient comparisons suggested better horizontal furcation responses with FDDMA. The findings of this study suggest equal clinical results with e-PTFE and FDDMA barriers utilizing the GTR technique. These results in Class II mandibular furcations are less favorable than those reported by others. Barrier techniques to handicap the race between different tissues of the periodontal complex appear to be of some clinical benefit and deserve further evaluation.

Adult↗
PubMed1992

Placement of hydroxyapatite-coated implants into fresh or recent extraction sites.

Factors important in the placement of HA-coated dental implants in fresh or recent extraction sites are case selection, treatment planning, and surgical modifications. The importance of good periodontal health and effective oral hygiene cannot be over-emphasized. Technique variations include careful extraction of the tooth or teeth, use of a surgical guide stent to overcome the "guidance" of the sockets, placement of the implants at least 1 mm apical to the socket edges, use of grafting materials to fill residual voids adjacent to the cylindrical implants, and special soft tissue closure techniques. Guided tissue regeneration methods are often used to enhance wound closure and improve bone regeneration around the implants. Clinical results suggest that HA-coated implants clinically integrate equally well in both fresh sockets and healed edentulous areas. Clinicians can comfortably consider placement of HA-coated dental implants in fresh extraction sockets for their patients and can anticipate favorable results with the application provided that the proper principles are followed.

Alveolar Process↗
PubMed1991

Histologic evaluation of combining tetracycline and allogeneic freeze-dried bone on bone regeneration in experimental defects in baboons.

Tetracyclines (TTC) have been used both systemically and locally during periodontal bone grafting procedures, but previous work regarding the effect of TTC on new bone formation has been contradictory. The purpose of this study was to determine if the use of locally applied TTC in combination with freeze-dried bone allografts (FDBA) would enhance bone regeneration in an experimental alveolar bone osseous defect grafting system. Pre-weighed freeze-dried bone allograft particles (300-500 mu diameter) were placed in nylon mesh chambers (250 mu pore size) and rehydrated with either 10 micrograms/ml aqueous TTC or sterile distilled water. Empty chambers were used as further controls. The chambers were placed in the posterior mandible of baboons in surgically created windows. After 3 and 5 weeks, the chambers were retrieved, processed histologically, and analyzed histometrically for new bone formation. The TTC-rehydrated FDBA demonstrated much greater (greater than 5x) new bone formation than the water rehydrated FDBA. These results strongly suggest that locally-applied TTC in combination with FDBA enhances new bone formation in experimental alveolar bone defects.

Administration, Topical↗
PubMed1991

Clinical comparison of hydroxyapatite-coated titanium dental implants placed in fresh extraction sockets and healed sites.

The placement of hydroxyapatite-coated dental implants in fresh extraction sockets was compared to placement in adjacent healed sites in 14 patients. Systematic sequential documentation was obtained regarding periodontal health, radiographic bone levels, and implant stability at the time of implant placement, at uncovering, and from 8 to 24 months (mean 16 months) after loading and restoration delivery. There were no significant differences in any clinical parameter between those implants placed in fresh extraction sockets and those placed in healed areas. Periodontal health, maintenance of crestal bone levels, and implant stability were excellent for implants placed in both types of recipient sites. The results of this study suggest that hydroxyapatite-coated dental implants can be successfully placed in fresh extraction sockets utilizing otherwise standard implant placement techniques, and that they appear to clinically perform equally well in fresh sockets and healed sites.

Adult↗
PubMed1990

HTR polymer grafts in human periodontal osseous defects. I. 6-month clinical results.

HTR polymer was evaluated as a grafting material in periodontal osseous defects in 21 adult patients. Following initial preparation and pre-surgical documentation with standardized measurements, radiographs, and photographs, vertical osseous defects were treated with surgical open flap debridement alone (DEBR) or with DEBR plus placement of HTR polymer graft material. Patients were followed with frequent recalls until surgical re-entry at about 6 months for documentation and any needed remedial therapy. Re-entry data show that use of HTR polymer grafts resulted in significantly better mean defect fill of 2.2 mm (60.8%) compared to 1.0 mm (32.2%) with DEBR alone (P less than .001). Other hard tissue findings such as residual defect depth, crestal resorption, and percent defect resolution showed similar clinically superior results with the use of HTR polymer. Soft tissue findings showed significant differences in favor of HTR for decrease in probing depth and gain in clinical attachment. These results are similar to those reported with other graft materials. Over a 6-month period, HTR polymer was found to show promise for the repair of periodontal osseous defects.

Adult↗
PubMed1990

A quantitative study of cementum removal with hand curettes.

An in vitro study was conducted to quantitatively measure the depth of root surface removal using curettes of standardized sharpness and with definite stroke number. Extracted periodontally healthy teeth from patients 10 to 15, 16 to 25, and 26 to 40 years old had periodontal ligament remnants removed with dry gauze before being secured in a vertical position during root planing. The force applied to the root surface was measured with a tension load cell. The "bright line" test was used to assess curette sharpness. After histologic processing, the thickness of cementum adjacent to the root defect, the cementum (if any) in the root defect, total amount of cementum removed, and depth of root defect were measured by a microscopic ocular grid. Teeth from each age range were evenly distributed into 6 groups of 10 teeth each. In the majority of teeth from the 20 stroke group through the 70 stroke group, complete cementum removal was observed at the site of planing. However, in some sections from each group, fragments of cementum remained on the root surface. A positive relationship (r/s = 1) was found between the number of strokes and the force applied to the root surface and the mean depth of defect (P less than 0.05). However, an inverse relationship existed between mean force per stroke and mean defect depth (r/s = -.99) such that as mean force per stroke increased, the mean defect depth decreased. As the root surface became smoother with an increasing number of strokes, the forces increased and were more consistent.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Osseous defect responses to hydroxylapatite grafting versus open flap debridement.

Data from a large number of defects (152) treated with hydroxylapatite (HA) grafts were compared to those from a large number of defects (111) treated by surgical debridement alone (DEBR). Comparison of initial and re-entry surgery measurements showed that both the analysis of relative defect fill and the intrapatient comparisons demonstrated an advantage to the use of HA graft material. 58% of the HA-grafted defects were judged to have a positive (greater than or equal to 50% defect fill) hard tissue response compared to 30% for DEBR. Minimal responses (failures) were 4 times as numerous with DEBR. Similarly, within each patient, HA grafting proved of benefit, particularly regarding hard tissue changes. The use of HA graft materials appears to be of clinical benefit in a majority of defects and a majority of patients.

Adult↗
PubMed1989

5-year evaluation of durapatite ceramic alloplastic implants in periodontal osseous defects.

Six patients who participated in a clinical study comparing the response of periodontal osseous defects to either grafting with Periograf (durapatite) hydroxylapatite (HA) ceramic or debridement alone (DEBR) were followed under an active maintenance program for 5 years. Mean values for gingival recession and attachment levels remained essentially stable following either treatment over the 5 year period. However, mean probeable pocket depths shifted from being significantly (P less than 0.05) shallower for DEBR sites at 6 months and 1 year to being significantly shallower for HA sites at 5 years. The probing pocket depth change for grafted sites was steady and the change from presurgical values was significantly greater than the change for DEBR areas, which became about 1.5 mm deeper over the 5 year postsurgical period. Intrapatient comparisons showed that recession, attachment gain, and pocket depth decrease were most frequently greater for the Periograf-treated sites. Assessment of the pattern of clinical changes during the 5 year postsurgical period demonstrated that the attachment level of grafted sites improved or stayed the same 86% of the time compared to only 62% stability or improvement in the DEBR only sites. In fact, 38% of the DEBR sites were worse at 5 years than at the time of surgery, a 3 times greater failure rate than that found in the HA-grafted sites. Pocket depth measurements showed that 98% of the Periograf-treated sites were better or the same as presurgically (2% worse), while only 80% of DEBR sites showed positive results and 20% had deeper pockets than at the time of surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Alveoloplasty↗
PubMed1989

Human freeze-dried dura mater allografts as a periodontal biological bandage.

Freeze-dried dura mater allografts (FDDMA) were used as a biologic bandage covering periodontal osseous defects which were grafted with autogenous bone particles. Seven consenting adult patients having multiple one-, two-, and wide three-wall periodontal osseous defects participated in the study. Four to 6 weeks following initial preparation, all defects were treated by full thickness flap surgery, debridement of defects, root planing, intramarrow penetration as needed, and autogenous bone grafts that filled the defects. Randomly selected grafted defects in each patient were then covered with FDDMA (experimental) or by the host flap (RF) (control). Periodontal dressing and systemic tetracycline (250 mg q.i.d.) were used for 7 days. Frequent maintenance was performed until reevaluation at 6 months postsurgically. Soft tissue results showed no significant differences in initial probing pocket depths, recession, or gain of probing attachment. There was a significantly greater amount of probing pocket depth reduction and significantly shallower residual pockets when FDDMA was used. Hard tissue findings indicated that there were no significant differences in initial defect depth, amount of crestal resorption, or amount or percent of defect fill with either treatment. There were significant differences in the percent of defect resolution and the depth of the residual defect in favor of the FDDMA treatment. None of the FDDMA sites were felt to need a secondary surgery to correct residual defects or residual pockets. This study suggests that FDDMA may be beneficial as a "biologic bandage" to cover periodontal osseous defects that were filled with autogenous bone grafts. The trends in this study suggest that FDDMA may be very useful in periodontal regeneration procedures.

Adult↗
PubMed1989

Effect of various graft materials with tetracycline in localized juvenile periodontitis.

Ten patients with bilateral, posterior osseous defects associated with localized juvenile periodontitis (LJP) completed the study. Following the initial therapy, osseous defects were surgically debrided and grafted with a 4:1 volume ratio combination of either Synthograft/tetracycline (b-TCP/TTC), Periograf/tetracycline (HA/TTC) or freeze-dried bone allograft/tetracycline (FDBA/TTC). Graft materials were selected randomly for each half mouth following defect debridement, with a different material used on the opposite side for that patient. Immediately following each surgery, patients were placed on doxycycline 100 mg/day for 10 days. Direct re-entry evaluation of 51 osseous defects demonstrated no significant differences among the graft materials regarding hard tissue or soft tissue changes, except for greater percent defect fill for HA/TTC compared to b-TCP/TTC. Significant decreases in defect depth and pocket depth were achieved with each graft material. No adverse reactions to the use of any of the graft materials in combination with local and systemic tetracycline were found. The results indicate all three graft materials used in conjunction with TTC are acceptable and beneficial for the treatment and repair of osseous defects associated with localized juvenile periodontitis.

Adolescent↗
PubMed1986

Relationship of maxillary molar root angulation and palatal vault height.

If the vertical angulation of maxillary molar roots could be reliably predicted, this might affect the choice of roots resection procedures. In an attempt to develop this prediction, angulation of palatal roots was compared to palatal vault height. Human cadaveric maxillae with molars were sectioned faciopalatally through each tooth root to the palatal midline and photographed. Root angles and palatal height were measured on the photographs in relation to a reference line connecting buccal and palatal cementoenamel junctions (CEJ). Palatal vault heights were classified as low, medium, or high according to the perpendicular distance from the midpalatal suture to the reference line. Root angles were subtended by a line following the length of pulp canals and perpendicular to the CEJ reference. Analysis by Spearman's Rank Correlation Coefficient demonstrated a weak nonsignificant relationship between palatal vault height and the angulation of the various maxillary molar roots. Thus, palatal vault height would not be a reliable predictor of root angulation if this were to be used as a basis for root retention.

Adult↗
PubMed1986

Juvenile periodontitis. I. Demonstration of local immunoglobulin synthesis.

The purpose of this investigation was to determine the presence and quantity of immunoglobulin G (IgG) and albumin (ALB) in specified periodontal tissues and serum from patients diagnosed as having juvenile periodontitis (JP), using an immunoelectrophoresis technique and to determine which portion of the lesion generated the greatest local immunoglobulin production. Serum and tissue samples were obtained from 19 patients (ages 13-21 years) who were diagnosed as having JP; 18 were female; 16 were black. Normal, diseased, and granulomatous gingival/periodontal tissues were collected during full thickness flap surgery, then minced, homogenized, and centrifuged. Supernatants containing the gingival/periodontal protein and the serum were electrophoresed against rabbit antihuman IgG and ALB. The relative IgG/ALB ratios in each specimen were plotted against known concentrations of IgG using a least squares analysis to provide evidence for local synthesis. In comparing mean IgG/ALB ratios for all tissue types, it was noted that normal gingiva did not differ significantly from serum. Diseased and granulomatous tissues, taken together or separately, had significantly higher IgG/ALB ratios than normal gingiva or serum, demonstrating that 73.6% of the IgG present was due to local synthesis. However, the greatest amounts of locally produced IgG were found in the granulomatous tissue from the deepest areas of the defects.

Adolescent↗