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Biomedical subjects

J Yancey

Publications and source records attributed to J Yancey.

11 recordsLinked to original sources
PubMed2000

Improved closure rate of Class III furcations using a layered GTR technique.

In this study, 24 furcation defects in 12 patients were treated by either (1) a polylactide resorbable membrane (Guidor) plus a polyglactin mesh (Vicryl) and demineralized freeze-dried bone allograft (DFDBA), or (2) a polylactide resorbable membrane and DFDBA. All defects were reentered after 9 months. Class III furcations closed 66% of the time when treated by the first method, while the closure rate was only 33% when treated by the second method (no polyglactin mesh). Defects with a vertical opening of < or = 4 mm closed 74% of the time, while those with vertical openings > 4 mm closed only 11% of the time.

Absorbable Implants↗
PubMed2000

Hard tissue ridge augmentation using a resorbable membrane and a particulate graft without complete flap closure.

Twelve patients with isolated alveolar ridge defects bordered by teeth on each side were treated and followed for 12 months. The treatment involved use of a resorbable membrane and a particulate graft without complete flap closure. Measurements taken at 12 months showed a significant mean osseous gain of 3.27 +/- 3.73 mm in mid-defect ridge width and an increase in height of 1.90 +/- 2.50 mm.

Absorbable Implants↗
PubMed2000

Improved bone regeneration and root coverage using a resorbable membrane with physically assisted cell migration and DFDBA.

Twelve patients with 2 Miller Class I or II buccal recession defects measuring > or = 3.0 mm were treated using the principles of guided tissue regeneration and followed for 12 months. The effectiveness of a polylactide (Guidor) resorbable membrane (GA sites) was compared to a combination treatment of polylactide membrane plus polyglactin root-lining mesh (Vicryl) and demineralized freeze-dried bone allograft (DFDBA) (GVB sites) designed to enhance cell migration and bone regeneration. There was 90% mean soft tissue root coverage for the GVB sites and 78% for the GA sites. The mean osseous dehiscence area coverage with hard tissue was 75% for GVB sites and 30% for GA sites.

Absorbable Implants↗
PubMed1999

The effect of postsurgical naproxen and a bioabsorbable membrane on osseous healing in intrabony defects.

BACKGROUND: Previous reports in the literature have shown that non-steroidal anti-inflammatory drugs (NSAID) may affect osseous tissues by either stimulating or inhibiting bone formation. This effect can be drug specific and different NSAIDs may produce opposite results. There are also reports showing that NSAIDs inhibit bone loss due to inflammatory disease process. The purpose of this randomized, controlled, blinded, clinical investigation was to determine the effect of a one week course of postsurgical naproxen on the osseous healing in intrabony defects. METHODS: Twenty-four vertical osseous defects in 24 patients were treated with either a bioabsorbable membrane plus twice daily postsurgical naproxen 500 mg for one week (test or GPN group) or with a polylactide bioabsorbable membrane alone (control or GA group). Twelve patients were included in each group. Treatment was performed on either 2- or 3-wall or combination defects. All measurements were taken from a stent by a calibrated, blinded examiner and open measurements were repeated at the 9-month second stage surgery. Power analysis to determine superiority of naproxen treatment showed that a 12 per group sample size would yield 87% power to detect a 2.0 mm difference and 64% power to detect a 1.5 mm difference. RESULTS: Open defect measurements from baseline to 9 months showed a statistically significant (P < 0.05) mean defect fill of 1.96 +/- 1.27 mm and 2.04 +/- 1.71 for the GPN and GA groups, respectively. This corresponded to a mean defect fill of 42% and a mean defect resolution of approximately 75% for both groups. The differences between GPN and GA groups were not statistically significant (P > 0.05). Defect fill of > or = 50% was seen in 6 defects (50%) in the GPN group and in 5 defects (42%) in the GA group. CONCLUSIONS: The administration of postsurgical naproxen failed to produce osseous healing that was statistically superior to that obtained with polylactide bioabsorbable membranes alone.

Absorbable Implants↗
PubMed1999

The effect of postsurgical antibiotics and a bioabsorbable membrane on regenerative healing in Class II furcation defects.

BACKGROUND: The purpose of this randomized, controlled, blinded, clinical investigation was to determine the effect of postsurgical antibiotics on osseous healing in Class II furcation defects. METHODS: Twenty-four Class II furcation defects in 24 patients were treated with either a polylactide bioabsorbable membrane, demineralized freeze-dried bone allograft (DFDBA) plus antibiotics (GBA or test group) or with a polylactide membrane and DFDBA alone (GB or control group). Twelve patients were included in each group. The antibiotic regimen consisted of ciprofloxacin 250 mg twice daily and metronidazole 250 mg tid for 1 week followed by a 7-week regimen of doxycycline hyclate 50 mg daily. Treatment was performed on either mandibular buccal or lingual, or maxillary buccal Class II furcation defects. Defects were randomly selected by a coin toss for treatment and all open and closed measurements were performed by a blinded examiner. Final open and closed measures from a stent were repeated at the 9-month second stage surgery. Power analysis to determine superiority of antibiotic treatment showed that a 12 per group sample size would yield 93% power to detect a 1.5 mm difference and 64% power to detect a 1 mm difference. RESULTS: Mean open horizontal probing depth reductions at 9 months were greater for the GBA group than for the GB group (2.92+/-1.78 versus 2.50+/-1.62 mm); however, these differences were not statistically significant. Seven of 12 furcations (58%) in the GBA group demonstrated >50% vertical defect fill at 9 months compared to 8 of 12 furcations (67%) in the GB group. There were no significant differences in mean open horizontal probing depth reduction between smokers and non-smokers in either the GBA or GB groups. Membrane exposure did not appear to affect regenerative healing in either the GBA or GB groups. CONCLUSIONS: The administration of postsurgical antibiotics did not produce statistically superior osseous healing of Class II furcation defects. This result may be attributable to membrane design which facilitates connective tissue ingrowth, thereby preventing bacterial downgrowth and contamination of the newly regenerated tissues.

Absorbable Implants↗
PubMed1996

Environmental "white noise": an intervention for verbally agitated nursing home residents.

This study presents preliminary data on the efficacy of two environmental "white noise" audiotapes for the treatment of verbal agitation in severely demented nursing home residents. The researchers employed a computer-assisted real-time observational system to assess both the frequency of verbal agitation and the actual use of the intervention on the nursing units (treatment fidelity). Intervention by nurse aides (NAs) on the unit was preceded by a researcher-controlled functional analysis phase that provided information regarding which of the two audiotapes would be most effective for individual residents. Results indicate a 23% reduction in verbal agitation with this individualized treatment strategy on the nursing units. These results were obtained even though treatment fidelity data showed that the audiotapes were used during only 51% of the observations. The authors discuss the need for formal staff management procedures for increasing staff compliance with treatment regimens.

Aged↗
PubMed1994

Direct digital imaging with and without niobium filtration for detection of density differences beneath steel orthodontic bands.

An in vitro investigation was carried out to determine the efficacy of the RVG 32000 (Trophy Radiologie, Vincennes, France) in detecting subtle density variations in a standard aluminum test object through steel orthodontic bands. The density variations were of the same magnitude as those found when dental caries develops beneath bands during orthodontic therapy. The procedure was carried out with both standard aluminum filtration and added niobium filtration. This study revealed the imaging system to have a wide recording latitude with no significant differences in the diagnostic decisions being made between with entrance doses ranging from 189-517 microGy without niobium, and 169-267 microGy with added niobium. No significant difference was found between the diagnostic yield of images made with and without added niobium filtration. The accuracy was 89% with added niobium and 90% without added niobium. Specificity was 99% for both filtration conditions. It was generally possible to detect defects as small as 0.2-0.3 mm in 7 mm of aluminum through 0.26 mm steel orthodontic band material. It is concluded that the RVG 32000 has a wide recording latitude which permits detection of small density changes beneath orthodontic band material. The addition of niobium filtration did not interfere with this diagnostic task.

Absorptiometry, Photon↗
PubMed1988

Can retinal adhesion mechanisms determine cell-sorting patterns: a test of the differential adhesion hypothesis.

Embryonic chick neural retina cells possess two classes of adhesion mechanism, one Ca2+-independent, one Ca2+-dependent, responsible for short-term cell aggregation. This study investigates the role of these mechanisms in the long-term cell sorting potentially relevant to in vivo histogenesis. Retina cells are prepared either with both (E cells) or with only one mechanism (TC cells, CD; LTE cells, CI), respectively. The two types of cell preparations are differentially labelled using fluorescein or rhodamine isothiocyanate, mixed and allowed to aggregate in the presence or absence of cycloheximide at 0.5 microgram ml-1 to retard metabolic recovery of the removed adhesive mechanism. When observed by fluorescence and phase-contrast microscopy, the aggregates formed in cycloheximide show cell sorting, the cells with both mechanisms assuming a more interior position relative to those with a single adhesion mechanism. In parallel hanging-drop experiments, preformed aggregates of cells with a single adhesion mechanism are seen to spread upon aggregates of cells with both mechanisms. No sorting occurs amongst cells from a given stage prepared using any single dissociation protocol. The observed cell sorting would thus seem to derive exclusively from differential cell adhesiveness dependent upon the different dissociation conditions and maintained in the presence of cycloheximide. The experiments support the hypothesis that the dual CI and CD adhesion mechanisms in question can play a central role in governing cell-sorting behaviour during normal histogenesis.

Animals↗
PubMed1987

Repeated measures analysis of geometrically constructed and directly determined cephalometric points.

Cephalometric landmarks were directly determined visually from bony anatomy on lateral cephalometric radiographs and compared with geometrically constructed cephalometric landmarks for repeated measures reliability of identification. Three groups of four orthodontists, grouped by level of experience, identified 18 landmarks on each of four cephalometric radiographs. This measurement procedure was repeated four times in 1-week intervals. The variability, main associations and interactions among the variables of tracer experience, quality of radiograph traced, and the anatomic landmarks traced were assessed by means of the repeated measures analysis of variance and follow-up Tukey HSD test. The coefficient of variation was used to compare the relative variability of replicate identification of the 18 cephalometric landmarks. Rank order and statistically significant groupings by variability are listed. The level of observer experience and quality of radiograph were statistically unrelated to landmark variability on replicate examination. The geometrically constructed landmarks tested were not statistically different from the reliability of the directly determined bony-based landmarks. This finding would lend support to the techniques of geometric construction used in the Ricketts cephalometric analysis.

Cephalometry↗