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PubMed2006

The influence of enamel defects on the development of early childhood caries in a population with low socioeconomic status: a longitudinal study.

The purpose of this study was to evaluate the influence of enamel defects in the development of dental caries and their association with feeding practices and oral health behaviors in a cohort study of low-socioeconomic children from birth to 36 months of age in northeastern Brazil. Subjects were registered at birth and examined from 12 to 36 months of age. At baseline, 246 children were examined and at follow-up 228. The teeth were clinically examined and dried with gauze under natural light. Enamel defects were determined using the Developmental Defects of Enamel (DDE) index. Dental caries was determined using WHO criteria. Data were analyzed using descriptive and analytical techniques. At 36 months 78.9% infants presented at least one tooth with enamel defects and 25% of the children had at least one decayed tooth. A total of 16.9% teeth with enamel defects had become decayed (p = 0.0001). Opacity with enamel hypoplasia was the defect most frequently associated with dental caries (p = 0.001). Only 0.9% of the teeth without enamel defects developed caries. Multivariate analyses revealed that enamel defects, night breast-feeding and poor oral hygiene habits were predictors of dental caries at 18 and 24 months (p < 0.05). Considering the risk factors evaluated at 30 months of age, the presence of enamel defects was the single predictor of caries development at 36 months (p = 0.0001). Enamel defects are strongly associated with early childhood caries and, therefore, this correlation must be considered when focussing on low-socioeconomic communities.

Bottle Feeding↗
PubMed1988

Characterizing hereditary and acquired defects of plasminogen.

Since plasminogen is the proenzyme of plasmin most acquired defects of plasminogen are associated with situations with an increased fibrinolytic activity. Congenital defects also have been described both such associated with thrombotic disease and such that are not. An increased fibrinolytic activity leading to an acquired plasminogen defect is seen 1) in situations complicated with a free proteolytic activity most often involving both the fibrinolytic and the coagulation systems, 2) as a result of locally increased fibrinolytic activity (angiomas), 3) during thrombolytic therapy using plasminogen activators (SK, UK, tPA). A congenital plasminogen defect characterized by 1) a low protein level as well as one with 2) a normal plasminogen protein level in plasma but a defect activation pattern has been reported. Plasminogen can be determined immunochemically, a method which does not differentiate between functionally active plasminogen/plasmin and complexes between these proteins and inhibitors. Plasminogen activity is measured in a chromogenic method using the chromogenic substrate S2251 (Kabi Diagnostica, Stockholm). In this latter method SK is used as a plasminogen activator and the total plasmin formed is measured amidolytically. Using both the immunochemical and the amidolytical methods it has been possible to identify congenital plasminogen defects characterized by a defective activation of plasminogen into plasmin, a defect that has been associated with thromboembolic disease. Another congenital plasminogen defect seems to be caused by a decreased synthesis of a normal plasminogen molecule. Such a defect may not be associated with thrombotic disease. In situations complicated with an increased fibrinolytic activity, decreased plasminogen levels (in both types of assay) are of diagnostic help. Values down to below 50% or even lower may be seen.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Coagulation Disorders↗
PubMed1998

Stress-induced reversible and mild-to-moderate irreversible thallium defects: are they equally accurate for predicting recovery of regional left ventricular function after revascularization?

BACKGROUND: In patients with coronary artery disease, stress-redistribution-reinjection thallium scintigraphy provides important information regarding myocardial ischemia and viability. Although both reversible and mild-to-moderate irreversible thallium defects retain metabolically active, viable myocardium, we hypothesized that stress-induced reversible thallium defects may better differentiate reversible from irreversible regional left ventricular dysfunction after revascularization. METHODS AND RESULTS: Twenty-four patients with chronic coronary artery disease underwent prerevascularization and postrevascularization exercise-redistribution-reinjection thallium single photon emission CT, gated MRI, and radionuclide angiography. After revascularization, mean left ventricular ejection fraction increased from 30+/-9% to 37+/-13% at rest (P<0.001). Before revascularization, abnormal contraction at rest was observed in 56 of 110 reversible and 20 of 37 mild-to-moderate irreversible thallium defects (51% and 54%, respectively). After revascularization, regional contraction improved in 44 of 56 reversible compared with 6 of 20 mild-to-moderate irreversible thallium defects (79% and 30%, respectively; P<0.001). The final thallium content (maximum tracer uptake on redistribution-reinjection images) was significantly higher in regions with reversible defects that improved than in those that did not improve after revascularization (86+/-16% versus 66+/-9%, P<0.001). In contrast, final thallium content was similar in regions with mild-to-moderate irreversible defects that improved and in those that did not improve after revascularization (69+/-9% versus 65+/-10%, P=NS). Furthermore, when asynergic regions were grouped according to the final thallium content, at 60% threshold value, functional recovery was observed in 83% of regions with reversible defects compared with 33% of regions with mild-to-moderate irreversible defects (P<0.001). CONCLUSIONS: These findings suggest that although both reversible and mild-to-moderate irreversible thallium defects after stress retain viable myocardium, the identification of reversible thallium defect on stress in an asynergic region more accurately predicts recovery of function after revascularization. Even at a similar mass of viable myocardial tissue (as reflected by the final thallium content), the presence of inducible ischemia is associated with an increased likelihood of functional recovery.

Adult↗
PubMed2002

Homonymous visual field defects and stroke in an older population.

PURPOSE: The objective of the present study was to describe the prevalence of homonymous visual field defects in a defined older urban population and associations with self-reported stroke. METHODS: Homonymous visual field defects were assessed from screening automated visual field tests of both eyes in 3654 persons aged > or =49 years who were participating in the Blue Mountains Eye Study. This represented 82.4% of eligible residents from a defined area west of Sydney, Australia. A detailed eye examination was performed, and the medical history was taken. Masked grading of visual fields was used to classify the presence of homonymous visual field defects. RESULTS: Homonymous visual field defects were found in 25 persons (prevalence 0.8%, 95% CI 0.5% to 1.1%). Stroke history was reported by 194 participants (5.3%, 95% CI 4.6% to 6.1%). A strong relationship was found between homonymous visual field defects and history of stroke, age-, and sex-adjusted odds ratio (OR) 23.4 (95% CI 9.9 to 55.7). Homonymous field defects were present in 8.3% of all persons who reported experiencing a stroke. Among those with homonymous field defects, 52% reported a history of stroke. Only 2 of 10 persons (20%) with homonymous field defects without a history of stroke reported having stopped driving, whereas 6 of 9 (67%) reporting stroke had stopped driving (P=0.07). Increasing age (OR 1.4 per decade, 95% CI 1.2 to 1.8) was significantly associated with homonymous visual field defects, with adjustment for sex, whereas a history of hypertension (OR 2.7, 95% CI 1.2 to 6.1), diabetes (OR 2.1, 95% CI 1.4 to 3.2), and renal impairment (OR 2.8, 95% CI 1.0 to 8.1) also was associated, with adjustment for age and sex. CONCLUSIONS: This study provides accurate prevalence data for homonymous visual field defects in an older population. About half the participants did not report stroke.

Age Distribution↗
PubMed1993

Radiographic secondary caries prevalence in teeth with clinically defective restorations.

Decisions to replace existing restorations are often based on clinical findings of margin discrepancies and other restoration defects. Previous studies have suggested that such findings do not correlate well with the actual presence of secondary caries, and that treatment should be deferred until caries is clinically or radiographically evident. The purpose of this study was to assess the frequency with which clinically defective restorations are associated with radiographic secondary caries. As part of a study to assess the efficacy of guidelines for the ordering of dental radiographs, 6285 restored teeth in 490 subjects were examined clinically and radiographically by three calibrated investigators. Specific criteria were used to determine whether restorations were intact or defective. Of the total, 822 teeth (13%) were judged to have clinically defective restorations. Of these, 113 teeth (14%) had radiographic secondary caries. Of the 5463 teeth with intact restorations, 5% had radiographic secondary caries. We found that the likelihood of radiographic secondary caries was nearly three-fold higher for defective restorations than for intact restorations. The large percentage (86%) of defective restorations with no radiographic secondary caries suggests, however, that replacement of all defective restorations due to risk of secondary caries may constitute overtreatment. The use of defective restoration status and presence of radiographic secondary caries as a combined criterion for replacement may potentially reduce such overtreatment. The prevalence of secondary caries under defective restorations should be determined clinically so that the usefulness of combining the criteria of defective restoration with those of radiographic secondary caries can be evaluated.

Analysis of Variance↗
PubMed2005

Treatment of osseous cleft palate defects: a preliminary evaluation of novel treatment modalities.

OBJECTIVE: To compare the use of autogenous iliac bone graft (ABG) alone with nonresorbable expanded polytetrafluoroethylene Gore-Tex TR membrane (GTM) and with ABG plus resorbable Resolut XT membrane barriers for the secondary closure of alveolar cleft defects. STUDY DESIGN: Fifteen patients aged 9 to 17 years with unilateral cleft palate were included in this study. All patients had primary closure of the soft tissues at infancy. Presurgical orthodontics and scaling preceded the surgery. The patients were randomized to one of three surgical treatment groups: (1) ABG, (2) GTM, or (3) autogenous bone plus resorbable membrane (ABM). Periapical radiographs were taken pretreatment and 2 to 6 years later and were used to measure changes in size (linear and area) of the osseous defect. RESULTS: Significant decreases were observed in mean initial defect width (9.8 to 6.7 mm; p = .0263), mean initial defect height (20.7 to 15.1 mm), and overall mean defect size (223.6 to 143.9 mm2). Greater improvement in mean defect width was observed for the ABM group (6.42 mm) compared with the ABG (1.22 mm) and GTM (1.38 mm) groups. The reduction in overall mean defect size was significantly greater in the ABM group (177 mm2) compared with the GTM (20.51 mm2) and ABG (41.69 mm2) groups. CONCLUSION: Guided bone regeneration was found potentially useful for the treatment of osseous cleft palate defects. The combined approach yielded significantly greater defect fill. If further substantiated in larger independent studies, the adjunctive use of barrier membranes could improve the management of secondary closure of cleft palate defects.

Absorbable Implants↗
PubMed1999

A multidisciplinary approach to the healing of cranial and residual maxillary cleft defects by means of allogenous demineralized osseous implants and polylactic acid casts in dogs.

OBJECTIVE: The aim of this study was to evaluate the healing of artificially induced bony defects in dogs by means of demineralized allogenous bone powder (DBP) implants covered with polyhydroxy lactic acid (PLA) casts compared with DBP implants without the casts. DESIGN: Prospective animal study. SETTING: Research university. SAMPLE: Following a pilot study in which two dogs were used, four mongrel dogs between the ages of 18 and 24 months and weighing approximately 20 kg were used as subjects. INTERVENTIONS: Each experimental animal had bilateral maxillary alveolar clefts created. In a later procedure, each defect was repaired with a DBP implant, half of which were covered with a PLA96 matrix. Each animal also had a circular defect created in each parietal bone that was immediately covered with DBP implants, half of which were similarly covered with a PLA96 disk. MAIN OUTCOME MEASURE: Repeated technetium-99m methylene-diphosphate (99mTC MDP) uptake measurements were performed to evaluate bone metabolism during the healing period, while at relevant intervals, radiographs were taken of the healing alveolar cleft defects to register bone repair. After 1 year, the animals were euthanized for macroscopic and histologic evaluation. RESULTS: Histologically, the grafts covered with PLA96 were at a more advanced stage of healing than those without, and the cranial defects similarly were more advanced in the healing process than the alveolar defects. Uptake of 99mTC MDP into the cranial implants was at its maximal level after 1 week and then gradually decreased until, after 7 weeks, it was not significantly different from zero. Cranial defects covered with a PLA95-enhanced implant showed a mean maximum count rate of 275, while the plain DBP side showed a mean maximal count rate of 150. Alveolar defects with the plain DBP implant showed a maximum count rate in the first week; those with the PLA95 enhanced implant showed maximum uptake during the second week. On both sides, there was a gradual decrease to the base value in the seventh week. The mean maximum count on the PLA96-enhanced side was 285, while on the plain DBP side, the corresponding value was 320. CONCLUSION: Although an advantage of the combination was established for parietal cranial defects, no advantage was seen for alveolar cleft defects in this experimental setup.

Alveoloplasty↗
PubMed1977

Periodontal osseous defects associated with vitally submerged roots.

1. Vital roots associated with periodontal osseous defects can be clinically submerged beneath a soft tissue flap. 2. Connective tissue fibers filled the submerged osseous defects and were oriented parallel to the root surfaces in the majority of cases. 3. New cementum lined the root surface at the base of two successfully submerged defects, but was not apparent on the dentin amputation sites of any submerged roots. 4. Eight of the nine clinically submerged defects exhibited positive radiographic changes. The six control defects showed no positive radiographic changes. 5. All successfully submerged defects showed histologic evidence of new bone formation. New bone formation was not apparent in any of the control defects or nonsubmerged defects. 6. Either no epithelium or only a narrow band of epithelium was associated with the successfully submerged roots. A connective tissue inflammatory infiltrate was not present within the submerged defects. 7. The defects of all control teeth and nonsubmerged experimental roots contained epithelial downgrowth accompanied by a chronic inflammatory response in the connective tissue. 8. Pulpal tissues associated with submerged roots appeared vital without significant degenerative or inflammatory changes. Pulpal tissue was continuous with overlying connective tissue.

Adult↗
PubMed1989

Relationship between the radiographic periodontal defect angle and healing after treatment.

This study radiographically evaluated the correlation between the changes in alveolar bone level occurring in bony defects after periodontal therapy and the corresponding pretreatment defect angles. The defect angle was defined by the bony defect surface and the root surface. The changes were determined from identically exposed and processed radiographs obtained just prior to surgery and 15 to 18 months later. The defect angle was clearly correlated to the radiographic changes in alveolar bone level. Most defects with an angle less than 45 degree showed a gain of bone while defects with the largest defect angles showed a loss. In addition, defects on root surfaces without furcations showed better healing than defects associated with furcations.

Alveolar Process↗
PubMed1998

Evaluation of a diphenylphosphorylazide-crosslinked collagen membrane for guided bone regeneration in mandibular defects in rats.

In the present study, the potential of a diphenylphosphorylazide-crosslinked type I bovine collagen membrane was evaluated in the healing of mandibular bone defects applying the biological concept of guided bone regeneration. The experiment was carried out on 25 Wistar rats. After exposing the mandibular ramus bilaterally, 5 mm diameter full-thickness circular bone defects were surgically created. While the defect on one side was covered by the membrane (experimental), the defect on the other side was left uncovered (control) before closure of the overlying soft tissues. The rats were sacrificed in groups of 5 after 7, 15, 30, 90, and 180 days of healing. Although at early stages of healing similar amounts of bone formation were observed in the experimental and control defects, after 1 month of healing, most of the experimental defects were completely closed with new bone, while in the control defects, only limited amounts of new bone were observed at the rims and in the lingual aspect of the lesions. In the 90- and 180-day animals, all experimental defects were completely closed, while in the control defects, no statistically significant increase in bone regeneration was observed. The increase in percentage of bone regeneration in the experimental defects was statistically significant between the 15-day specimens as compared with the 7-day specimens (P < 0.01) and likewise between 30-day and 15-day specimens (P < 0.001). It can be concluded that a DPPA-crosslinked collagen membrane yields biocompatibility, ad hoc mechanical hindrance, and handling characteristics suitable for guided bone regeneration applications in this experimental model.

Alveolar Bone Loss↗
PubMed1998

Multi-center clinical evaluation of combination anorganic bovine-derived hydroxyapatite matrix (ABM)/cell binding peptide (P-15) as a bone replacement graft material in human periodontal osseous defects. 6-month results.

A synthetic cell-binding peptide (P-15) combined with anorganic bovine-derived hydroxyapatite bone matrix (ABM) was compared to demineralized freeze-dried bone allograft (DFDBA) and open flap debridement (DEBR) in human periodontal osseous defects in a controlled, monitored, multi-center trial. Following appropriate initial preparation procedures, flap surgery with defect and root debridement was performed. Three osseous defects per patient were treated randomly with one of three procedures after surgical preparation. Appropriate periodontal maintenance schedules were followed, and at 6 to 7 months re-entry flap surgery was performed for documentation and finalization of treatment. Analysis of variation (ANOVA) and t test analyses of patient mean values from 31 patients revealed that the combination ABM/P-15 grafts demonstrated significantly better mean defect fill of 2.8 +/- 1.2 mm (72.3%) versus a mean defect fill of 2.0 +/- 1.4 mm (51.4%) for defects treated with DFDBA (P <0.05) and a mean defect fill of 1.5 +/- 1.3 mm (40.3%) (P <0.05) for defects treated with DEBR. Other hard tissue findings showed similar clinically superior results with the use of ABM/P-15. Relative defect fill results showed 87% positive (50% to 100% defect fill) responses with ABM/P-15, 58% positive responses with DFDBA, and 41% positive responses with DEBR. There were 8 to 9 times more failures (minimal response) with DFDBA and DEBR (26% to 29% frequency) than with ABM/P-15. Soft tissue findings showed no significant differences among treatments except for greater clinical attachment level gain with ABM/P-15 compared to DEBR. These results suggest that the use of the P-15 synthetic cell-binding peptide combined with ABM yields better clinical results than either DFDBA or DEBR. Further studies are needed to determine the relative roles of the ABM and/or the P-15 in these improved results.

Adult↗
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↗
PubMed2001

Comparison of calcium sulfate and autogenous bone graft to bioabsorbable membranes plus autogenous bone graft in the treatment of intrabony periodontal defects: a split-mouth study.

BACKGROUND: Current literature shows that calcium sulfate can be used in guided tissue regeneration. Its biocompatibility and resorbability give it significant advantages in the treatment of periodontal and endodontic defects. Clinically guided tissue regeneration procedures have demonstrated significant positive clinical change, beyond that achieved with debridement alone, in treating intraosseous defects. The aim of the present investigation was to evaluate the clinical results obtained with autologous bone plus calcium sulfate, and to compare them with the results obtained using autologous bone plus membrane. METHODS: A total of 12 patients were treated in the present investigation. A split-mouth design was utilized. Twelve 3-wall periodontal defects were treated with calcium sulfate plus autologous bone graft (test) and compared with 12 contra-lateral defects treated with a bioabsorbable membrane plus autologous bone graft (control). Before the surgical procedure, patients were instructed about oral hygiene and scaling and root planing (SRP) was completed. Probing depth (PD), clinical attachment level (CAL), and bleeding on probing (BOP) were recorded at baseline and 6 months. RESULTS: There were no statistical differences between test and control defects at baseline. BOP was 58% and 50% for control and test defects, respectively. Mean PD was 7.75+/-0.96 mm (control) and 8.0+/-1.28 mm (test). Mean CAL was 8.58+/-1.31 mm (control) and 8.83+/-0.91 mm (test). At 6 months, mean PD was 3.41+/-0.51 (P = 0.0022) for control defects and 3.58+/-0.51 (P = 0.0022) for test defects. CAL showed a mean gain of 5+/-0.85 for controls (P = 0.0022) and 5.25+/-0.75 for test defects (P = 0.0022). Thus, there was a mean reduction of PD of 4.33 mm (56%) for control sites and 4.42 mm (55%) for test sites. The mean clinical attachment gain was 3.57 mm for control sites and 3.58 mm for test sites. As there were no sham-operated controls, it is not clear that the healing of these test or control-treated sites was any better than similar 3-walled defects sham operated. CONCLUSIONS: Both therapies led to short-term improvement of the measured parameters; neither was superior to the other.

Absorbable Implants↗
PubMed2003

Effect of recombinant human bone morphogenetic protein-2 in dehiscence defects with non-submerged immediate implants: an experimental study in Cynomolgus monkeys.

BACKGROUND: Alveolar ridge aberrations commonly compromise optimal dental implant installation. To offset any variance between an aberrant alveolar ridge and prosthetic designs, bone augmentation procedures become necessary. The objective of this study was to evaluate bone formation and osseointegration at alveolar dehiscence defects following augmentation of the defect site with recombinant human bone morphogenetic protein-2 (rhBMP-2) in an absorbable collagen sponge carrier (ACS) at dental implant installation including transmucosal positioning of the dental implant. METHODS: Four adult male Cynomolgus monkeys received dental implants in contralateral extraction socket sites with surgically created 6 x 4 mm buccal dehiscence defects following elevation of mucoperiosteal flaps. Contralateral sites received rhBMP-2/ACS (rhBMP-2 at 1.5 mg/ml; 0.1 mg/defect) or served as sham-surgery controls. The flaps were adapted and sutured around the healing abutments leaving the implants in a transmucosal position. The animals were sacrificed at 16 weeks postsurgery and block sections of the implant sites were harvested and prepared for histometric analysis. RESULTS: One dental implant from each treatment group failed to osseointegrate. Another 3 dental implants (sham-surgery controls) failed to osseointegrate with newly-formed bone in the defect area. Thus, 7 of 8 defect sites (4/4 animals) receiving rhBMP-2/ACS compared to 4 of 8 sites (2/4 animals) receiving sham-surgery exhibited evidence of osseointegration with newly formed bone in the defect area. Mean +/- SD defect height amounted to 5.3 +/- 0.2 and 5.4 +/- 0.1 mm for the rhBMP-2/ACS and sham-surgery sites, respectively. Vertical bone gain in rhBMP-2/ACS treated defects (3.9 +/- 0.3 mm) did not differ significantly from that in the sham-surgery control (3.7 +/- 0.4 mm; P > 0.05; paired t-test, N = 4). There were also no significant differences noted for coronal bone-implant contact (3.0 +/- 0.6 versus 3.6 +/- 0.5 mm), and bone-implant contact within the defect site (28.5% +/- 15.1% versus 27.4% +/- 31.7%) and within resident bone (46.9% +/- 26.8% versus 47.8% +/- 39.4%) for the rhBMP-2/ACS and control sites, respectively. CONCLUSIONS: The observations in this study point to a substantial native osteogenic potential of the alveolar process that has previously not been explored and show that surgical reentry observations of new bone formation may not necessarily indicate that osseointegration has occurred. Bone formation in control defects was substantially greater than predicted, limiting the value of adding an osteoinductive biologic construct.

Absorbable Implants↗
PubMed2003

Comparison of porous and non-porous teflon membranes plus a xenograft in the treatment of vertical osseous defects: a clinical reentry study.

BACKGROUND: The primary aim of this 9-month randomized, controlled, blinded, clinical reentry study was to compare the regenerative effects of a nonporous polytetrafluoroethylene (NP) periodontal membrane to a porous expanded polytetrafluoroethylene (P) periodontal membrane in the treatment of vertical osseous defects. METHODS: Twenty-four patients, 11 males and 13 females, age 24 to 74 (mean 50.5 +/- 13.1) provided one site with an intraosseous defect > or = 4 mm and were divided equally and randomly into two groups. Following debridement both groups were grafted with a bovine-derived xenograft coated with a synthetic cell-binding peptide; then the test group received an NP membrane and the control group received a P membrane. All defects were reentered after 9 months. Measurements were performed by a masked examiner. RESULTS: There were no statistically significant differences (P>0.05) between NP and P groups for any open or closed probing measurement at any time. Similar open initial defect depth for the NP group and P groups (4.8 versus 5.0 mm) demonstrated identical 9-month defect fill of 2.8 mm (57%) for both groups. A difference in crestal resorption for the NP compared to the P group (0.4 versus 0.8 mm) accounted for the difference in mean percent defect resolution, which was 67% for NP compared to 72% for the P group. Overall, nine (75%) of the NP group defects and eight (67%) of the P group defects showed more than 50% defect fill. CONCLUSION: Treatment of vertical osseous defects with nonporous or porous polytetrafluoroethylene membranes in combination with a xenograft resulted in statistically significant improvement in open and closed probing measurements, with no significant difference between treatment groups.

Adult↗
PubMed2006

Use of genetically engineered bone-marrow stem cells to treat femoral defects: an experimental study.

BACKGROUND: Treatment of osteonecrosis continues to be a challenging problem. The replacement of necrotic bone with graft materials that promote osteogenesis and angiogenesis may provide better outcomes for early stage disease. In this study, genetically engineered bone-marrow stem cells were used to enhance repair of a defect in the distal aspect of the femur. METHODS: Cloned bone-marrow stem cells were transfected with traceable genes. Osteoblastic and angiogenic properties of the cells were analyzed. A defect was created bilaterally in the distal portion of the femur of twenty-four mice to mimic a core decompression procedure. The cloned cells were transplanted into each defect of the right femur while the left femur served as control. Bone formation was evaluated radiographically and histomorphometrically. In addition, in twenty-four additional mice, the cells were injected into subcutaneous sites, muscles, and into the renal capsule (eight mice in each group) to evaluate ectopic osteogenesis. RESULTS: Radiopaque tissue appeared two weeks after the cells were transplanted into bone defects and at ectopic sites. Histologic analysis demonstrated that these tissues consisted of newly formed bone from transplanted cells that expressed traceable genes. Four of six bone defects that received cell transplantation were filled with new bone at four weeks, and all of the defects (n = 6) demonstrated complete healing at six weeks. On the control side, complete repair was seen in only two of six bone defects at four weeks and in three of six defects at six weeks. Histomorphometric analysis showed that transplantation of marrow stem cells into bone defects produced more bone at an earlier time-point than occurred in the controls. CONCLUSIONS: This study demonstrated that cloned bone-marrow stem cells can directly form bone after transplantation into bone defects and at ectopic sites, indicating that the in vitro expanded bone-marrow stem cells can serve as a graft material to enhance bone repair and to treat osteonecrosis. CLINICAL RELEVANCE: As an alternative graft material, bone-marrow stem cells may provide new and as yet technologically unachievable solutions to many clinical problems in the areas of musculoskeletal reconstruction and tissue regeneration.

Animals↗
PubMed1999

Prevalence of anal sphincter defects revealed by sonography in 335 incontinent patients and 115 continent patients.

OBJECTIVE: The aim of this study was to compare the prevalence of anal sphincter defects on anal sonography of incontinent and continent patients. SUBJECTS AND METHODS: Four hundred sixty-eight consecutive subjects who underwent anal sonography were studied. The prevalence of anal sphincter defects was calculated in 335 incontinent patients, 115 continent patients, and 18 asymptomatic female volunteers. All subjects answered a questionnaire about childbirth and proctologic surgery. RESULTS: The prevalence of anal sphincter defects revealed on sonography was 65% in the 335 incontinent patients. The prevalence of anal sphincter defects in incontinent patients was 88% in patients with a history of childbirth and proctologic surgery and 62% with childbirth alone. The prevalence of anal sphincter defects revealed on sonography was 43% in continent patients and 22% in asymptomatic volunteers. The prevalence of anal sphincter defects in continent patients with a history of childbirth and proctologic surgery was 92% and was 41% with childbirth alone. We found no difference in the prevalence of sphincter defects according to the age and sex of patients. CONCLUSION: Anal sonography can be used to identify sphincter defects in approximately two thirds of incontinent patients. Prevalence is greater in patients with a history of proctologic surgery. Because of the presence of sphincter defects in continent patients and in asymptomatic volunteers, caution should be used in attributing incontinence to anal sphincter defects alone.

Adolescent↗
PubMed1999

Quality assurance in PET: evaluation of the clinical relevance of detector defects.

UNLABELLED: Defective detector blocks in PET may cause serious image artifacts. To estimate the influence of malfunctioning detectors on image quality, a method is described for transferring the actual detector defect onto previously acquired scans. METHODS: Consequences of detector defects of varying types and extensions were simulated in phantom studies as well as in clinical 18F-fluorodeoxyglucose investigations. First, a condition frame was obtained by dividing the sinogram of a blank measurement, obtained with rod sources on the defective PET camera, by the sinogram of a reference blank acquired before the appearance of the defect. Second, the sinogram of a previously acquired typical patient study was multiplied by the condition frame and reconstructed. Thereafter, images from corrupted sinograms were compared visually with their originals. For repairing defective sinograms, linear interpolation and the constrained Fourier space method were tested. RESULTS: The effects of detector defects can be simulated accurately in patient studies. The correction methods applied are especially helpful in cases of (a) several neighboring defective detectors and small study objects, (b) small hot artifacts and (c) several nonadjacent defective detectors. Linear interpolation is faster than the constrained Fourier space method; it is more widely applicable and provides similar results. CONCLUSION: The proposed approach allows specific evaluation of clinical consequences of detector defects. This technique simplifies the decision as to whether a planned patient study can be performed or must be postponed. Even in cases of serious detector problems, sinogram repair may help eliminate image artifacts and minimize the loss of image quality.

Artifacts↗