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PubMed2006

Demineralized freeze-dried bone allograft and platelet-rich plasma vs platelet-rich plasma alone in infrabony defects: a clinical and radiographic evaluation.

The objective of this work is to compare the clinical and radiographic outcomes of demineralized freeze-dried bone allograft (DFDBA)/platelet-rich plasma (PRP) combination with PRP alone for the treatment of infrabony defects 18 months after surgery and to examine the influence of radiographic defect angle on the clinical and radiographic outcomes. Twenty-eight infrabony defects were treated with DFDBA/PRP combination or PRP alone. Clinical parameters and radiographic measurements were compared at baseline and 18 months. Interquartile range was performed to classify the defect angles. Mann-Whitney, Wilcoxon test, and Pearson correlation were used to analyze the data. The DFDBA/PRP combination exhibited more favorable gains in both clinical and radiographic parameters than PRP alone group (p < 0.05). A correlation existed between defect angle, defect depth, and clinical/radiographic outcomes for the defects treated with DFDBA/PRP. The narrow defects presented more favorable clinical attachment level values (CAL) gain, probing pocket depth (PPD) reduction and defect resolution than wide defects in the combination group (p < 0.05). The influence of baseline defect angle was not significant in the PRP-alone group (p > 0.05). The results indicate that DFDBA/PRP combination is more effective than PRP alone for the treatment of infrabony defects, and the amount of CAL gain, PPD reduction, and bone fill increases when the infrabony defect is narrow and deep before DFDBA/PRP combination treatment.

Adult↗
PubMed2005

Surgical repair of temple defects after Mohs micrographic surgery.

BACKGROUND: It is typically recommended that linear surgical closures follow a relaxed skin tension line (RSTL). In the temple, these lines generally run parallel to the orbital rim. However, closures parallel to RSTLs are not feasible for many medium and large surgical defects because of anatomic constraints. OBJECTIVES: We sought to describe our method of repairing temple defects and assess the cosmetic outcome of temple defects repaired perpendicular to the RSTLs. METHODS: We performed a two-phase study of temple closures. In the first phase, a retrospective analysis was performed to assess the defect size and type of closure used for 99 consecutive temple defects. In the second phase, 27 of 86 patients who previously underwent linear surgical repairs in the temple that were designed perpendicular to the RSTLs were evaluated 12 to 24 months postoperatively to assess the cosmetic outcome. Results In the first phase of the study, there was an inverse correlation between the width of the postoperative defect and the ability to close the defect parallel to the RSTLs. The percentage of defects that could be repaired parallel to the RSTLs for defects up to 1 cm in width, 1.1 to 2 cm in width, and greater than 2 cm in width was 46%, 28%, and 8%, respectively. In the second phase of the study, 27 patients with temple defects repaired perpendicular to the RSTLs were evaluated an average of 1.7 years after operation. Most scars (83%) were clinically invisible or barely visible. There were no cases with residual standing cones (dog-ears) or hypertrophic scars. CONCLUSION: The vast majority of temple defects can be repaired in a linear fashion. Smaller defects (width < 1 cm) can be repaired parallel to the RSTL. Those that are larger (width 1-3 cm) or more medially located can be repaired perpendicular to the RSTL, using loose cheek skin for the closure. Very large defects (width > 3-5 cm) or those with limited cheek mobility may require flaps or skin grafts for closure.

Cosmetic Techniques↗
PubMed1996

Relation between perfusion defects on stress technetium-99m sestamibi SPECT scintigraphy and the location of a subsequent acute myocardial infarction.

Although the presence of perfusion defects on stress myocardial perfusion imaging has been shown to correlate with future cardiac events, including acute myocardial infarction (AMI), it is unknown whether the location of the AMI can be predicted. Therefore, for 25 patients who had an AMI following a stress technetium-99m sestamibi single-photon emission computed tomographic (SPECT) imaging study and whose infarct location could be determined, the territory of infarction was correlated with the location of previous myocardial perfusion defects. A SPECT perfusion defect had been present in 24 patients (96%). The AMI occurred in territories that showed a reversible defect in 14 patients (56%), whereas 3 infarctions (12%) were in territories that revealed a fixed defect, and 8 infarctions (32%) were in territories that had not shown a defect on prior SPECT imaging. Whereas the incidence of infarction in territories with a reversible defect was highest at 14 of 26 (54%), the incidence of infarction in territories with a fixed defect was 3 of 7 (43%), and in territories with no defect was 8 of 42 (19%) (p = 0.011). Neither the time interval between SPECT imaging and infarction, nor the perfusion defect severity, was related to the correlation between perfusion defect and infarct location. Thus, although AMI occurs most often at the site of previous perfusion defects, reversible or fixed, a substantial percentage occur in territories without a perfusion defect. These findings suggest that abnormalities on SPECT perfusion imaging, although they serve as markers of significant coronary disease and increase the likelihood of infarction, do not always predict the exact location of infarction.

Aged↗
PubMed2001

Role of frequency doubling perimetry in detecting neuro-ophthalmic visual field defects.

PURPOSE: To report the ability of frequency doubling perimetry to detect "neuro-ophthalmic" field defects, characterize them as hemianopic or quadrantanopic, and differentiate glaucomatous from "other" neuro-ophthalmic field defects. METHODS: Sixty eyes of 30 normal subjects, 50 eyes of 29 patients with glaucomatous defects, and 138 eyes of 103 patients with "typical" neuro-ophthalmic field defects underwent automated perimetry using the Swedish Interactive Threshold Algorithm and frequency doubling perimetry. The sensitivity and specificity for identification of a field defect (frequency doubling perimetry 20-5 and 20-1 screening tests), or to characterize hemianopia/quadrantanopia (full threshold test) were determined. Ability to discriminate glaucomatous defects was determined by comparing frequency doubling perimetry full threshold test in glaucoma to pooled results of normal and neuro-ophthalmic groups. RESULTS: On frequency doubling perimetry, a single point depressed to less than 1% probability had a sensitivity of 97.1% (20-5 test) and 95.7% (20-1 test) for detecting a neuro-ophthalmic visual field defect. The corresponding specificities were 95% using pooled results in normal subjects and patients with glaucoma and "other" neuro-ophthalmic field defects. In 20-5 screening a single abnormal point depressed to less than 2% probability level had a sensitivity of 98.6% (specificity 85%). Two abnormal points in the 20-1 screening depressed to less than 1% probability level had a specificity of 100% (sensitivity 84.8%). In frequency doubling perimetry full threshold, sensitivity and specificity for detection of hemianopia were 86.8% and 83.2%; for quadrantanopia they were 79.2% and 38.6%. The sensitivity and specificity for categorizing a defect as glaucomatous were 86% and 74.7%. CONCLUSIONS: Frequency doubling perimetry is a sensitive and specific test for detecting "neuro-ophthalmic" field defects. The presence of two abnormal points (20-1 screening program) "rules in" the presence of a field defect. A normal 20-5 program (absence of a single abnormal point) almost "rules out" a defect. Frequency doubling perimetry could not accurately categorize hemianopic, quadrantanopic, or glaucomatous defects.

Child↗
PubMed1995

Topical fibronectin ophthalmic solution in the treatment of persistent defects of the corneal epithelium. Chiron Vision Fibronectin Study Group.

PURPOSE: We sought to evaluate the efficacy of topical fibronectin ophthalmic solution, containing 3.5 mg/ml of human fibronectin, in the treatment of persistent epithelial defects of the cornea. METHODS: In a double-masked, randomized clinical trial, patients with a persistent, corneal epithelial defect of at least 14 days in duration, and at least 2 mm in width along the larger axis, were sought from the practices of 38 clinical investigators. After a 14-day washout period, 65 patients were randomly assigned to one of three treatment groups. One group (n = 20) received fibronectin drops; the second (n = 23) received drops of the vehicle from the fibronectin solution; and the third (n = 22) received a placebo. RESULTS: After 21 days of treatment, there was no difference in percentage reduction of the corneal epithelial defect size; the average percentage of reduction of defect area ranged from 46.5% to 54.3%. Fibronectin treatment showed a beneficial effect for patients with larger baseline defects (10 mm2 or greater in area); however, no such effect was observed among patients with smaller defects. Defect duration before treatment had a significant effect on outcome (P = .007); defects of longer duration were less likely to decrease in size over the course of the study. CONCLUSIONS: All three treatment groups showed similar reductions in defect size; therefore, this study provides no support for the efficacy of fibronectin treatment of persistent, corneal epithelial defects. Defect duration showed a negative association with reduction in defect size. Because strict control of topical applications during the washout and treatment periods resulted in beneficial responses, physicians should carefully consider the topical medications used by patients who have persistent, corneal epithelial defects.

Administration, Topical↗
PubMed2003

Correlation between filling defect patterns on urography and pathologic staging of ureteral transitional cell carcinomas.

Although a filling defect within the ureter is the most common finding with ureteral transitional cell carcinomas (TCCs), little is known about the correlation between filling defect patterns and pathologic findings. This study was conducted to address this. Between January 1995 and January 2003, 126 pathologically confirmed TCCs of the ureter were included in our study. We classified urographic filling defects into four patterns: ovoid, polypoid, infiltrating, and plaque-like. The correlation between different filling defect patterns and pathologic findings was assessed using Pearson's Chi-squared and logistic regression methods. There were 28 (22%) ovoid filling defects, 42 (33%) polypoid filling defects, 37 (29%) infiltrating filling defects, and 19 (15%) plaque-like filling defects. Infiltrating and plaque-like filling defects were significantly associated with more advanced disease compared to ovoid and polypoid filling defects (odds ratio, 6.75; 95% confidence interval, 3.04-14.98; p < 0.0001). Our results suggest that filling defect presentations may signify different invasive behavior among TCCs. The distribution of ovoid, polypoid, infiltrating, and plaque-like filling defect patterns is significantly different between superficial and advanced ureteral TCCs. We suggest that classifying the filling defect patterns of ureteral TCCs may provide important preoperative information for planning treatment and predicting outcome.

Adult↗
PubMed1996

Directional defects in pursuit and motion perception in humans with unilateral cerebral lesions.

We tested motion perception and smooth pursuit in 26 patients with unilateral cerebral hemispheric lesions. We used random dot cinematograms to test motion direction discrimination. We measured pursuit gain as they followed a predictable sinusoidal target moving horizontally at three different frequencies, and an unpredictable horizontal step-ramp target in the ipsilateral hemi-field. Six patients had defects in motion perception when the targets were moving towards the side of the lesions ('ipsi-directional' defects) and two had bi-directional defects. Motion perception defects occurred with lesions of the junction of Brodmann areas 19 and 37, a putative human homologue of the monkey V5 complex. Seven patients had ipsi-directional pursuit defects, five of whom had damage to the posterior limb of the internal capsule. Only two patients had ipsi-directional defects of both motion perception and sinusoidal smooth pursuit. Four patients had ipsi-directional defects of motion perception alone, and five patients had ipsi-directional pursuit defects alone. The two patients with bi-directional defects in motion perception had normal sinusoidal smooth pursuit. Patients with lesions at the 19/37 junction and defects of motion perception alone had normal pursuit of unpredictable step-ramp targets in the ipsilateral hemi-field. In contrast, patients with ipsi-directional sinusoidal pursuit defects had decreased ipsi-directional and increased contra-directional velocities with step-ramp targets. No patient group had a motion-specific directional defect in saccadic accuracy. We conclude that neither predictable nor unpredictable pursuit is necessarily impaired by lesions of the 19/37 junction that cause ipsi-directional defects of motion perception. These dissociations between smooth pursuit and motion perception provide evidence that the pursuit system operates as an interconnected network with parallel pathways, rather than as a simple sequential hierarchy of cortical areas.

Adult↗
PubMed2002

Bone tissue engineering: treatment of cranial bone defects in rabbits using self-reinforced poly-L,D-lactide 96/4 sheets.

This study is one of a series in which the authors evaluate various absorbable sheets to guide bone regeneration in cranial bone defects. The aim was to evaluate the use of self-reinforced poly-L,D-lactide 96/4 (SR-PLA96) sheets for cranial bone tissue engineering in experimental defects in rabbits. Square defects of 10 x 10 mm were created in the right parietal bone. SR-PLA96 implants (15 x 15 mm) were used to cover these defects in 12 New Zealand White rabbits. Similar defects were created in the left parietal bone, but no sheets were used (controls). The rabbits were killed after 6, 24, or 48 weeks. Histology and histomorphometry were used to evaluate healing of the defects. Defects covered with SR-PLA96 sheets showed more abundant bone formation than control (non-covered) defects. At 6 weeks, the defects were occupied mainly by fibrous tissue. At 24 weeks, healing with bone formation was more obvious in the covered defects. At 48 weeks, bone completely bridged defects covered with SR-PLA96 sheets, and incomplete bridging was seen in non-covered control defects. Hence, bone tissue engineering in experimental cranial bone defects in rabbits can be achieved using SR-PLA96 sheets to guide bone regeneration.

Absorbable Implants↗
PubMed1997

Recognition of subsegmental scintigraphic defects in virtual lung scintigraphy.

A virtual model of the segmental scintigraphic anatomy of the lungs was used to investigate the threshold at which small defects are perceptible. A model of the segmental anatomy of the lungs was developed from a number of sources and counts generated within the phantom by Monte-Carlo simulation of photon emission. Multiple subsegmental defects were created in both lungs and submitted for blinded reporting to detect the presence of any defect. A total of 36 of the 47 (77%) defects were seen. Of those defects in the lower lobes, 16 of 22 (73%) were visible. All the defects in the left lung (n = 21) were visible, while 15 of 26 (58%) of the defects on the right were visible. In the lower lobe of the right lung, 4 of 10 defects were visible. The defects that were not visible were all in the right lung. We conclude that absolute size and location are critical in the perception of defects. The perception of defects was dependent on absolute defect size rather than the proportion of a segment involved. Defects less than 3% of the volume of a lung were not detected.

Humans↗
PubMed1978

Osseous repair in infrabony periodontal defects.

The present investigation was undertaken to quantitate the osseous changes which occur throughout the entire circumferential extent of infrabony periodontal defects in patients with optimal plaque control. Fifteen defects were selected in nine patients. Periodontal surgery was scheduled after each patient had shown an ability to practice efficient plaque removal. Muco-periosteal flaps were raised and the osseous defects debrided. The dimensions of each defect were measured at several specific location points within the defect. The flaps were replaced at their original location and, post-operatively, optimal plaque control was maintained in the area (Mean Plaque Index 0.04). Six to 8 months after the initial surgery all areas were re-operated and the osseous defects were remeasured at the same specific location points. Each defect showed osseous regeneration at every location point. The mean initial osseous defect depth at a location point was 3.5 mm and the mean amount of bone regeneration which occurred was 2.5 mm. Crestal alveolar bone resorption occurred at almost half of the location points and averaged 0.7 mm. Eleven of the 15 defects had resolved completely. There were isolated areas where a shallow defect persisted in the remaining four defects. The behavior of an osseous defect throughout its circumferential extent was characterized by a combination of coronal bone regeneration (mean 77%) and marginal bone resorption (mean 18%). Infrabony periodontal defects may predictably remodel after surgical debridement and establishment of optimal plaque control.

Adult↗
PubMed1992

Positron emission tomography detects metabolic viability in myocardium with persistent 24-hour single-photon emission computed tomography 201Tl defects.

BACKGROUND: Four-hour 201Tl redistribution images underestimate myocardial viability in patients with coronary artery disease (CAD). Because 4-hour defects often redistribute late, delayed imaging may enhance assessment of tissue viability. Myocardial metabolic activity was therefore assessed with positron emission tomography (PET) in 26 CAD patients with impaired ventricular function (ejection fraction, 32.1 +/- 13.9%) and 24-hour single-photon emission computed tomography (SPECT) 201Tl defects. METHODS AND RESULTS: On circumferential profile analysis, PET ischemia was defined by preserved glucose metabolism in hypoperfused myocardium, and PET infarction was defined by concordant reductions in perfusion and metabolism. On 19 stress-redistribution and seven rest-redistribution SPECT studies, four observers visually scored 201Tl activity in eight segments on a scale from 0 (normal) to 3 (complete defect). Using an improvement in visual score > or = 0.75 to define redistribution, there were 100 fixed, 17 partially reversible, and 12 completely reversible defects. PET identified tissue metabolic activity in 51 (51%) segments with fixed defects (21 PET ischemia, 30 PET normal) and nine (53%) segments with partially reversible defects (five PET ischemia, four PET normal). When grouped by 24-hour score, the proportion of fixed defects with metabolic activity varied from 84% (scores < or = 1.4) to 15% (scores > 2.6). For partially reversible defects, only 53% with scores < 2.0 and one of two with scores > or = 2.0 were considered metabolically viable on PET. Of 12 completely reversible defects, six (50%) were normal, five (42%) had PET ischemia, and one (8%) had PET infarction. The proportion of fixed defects with metabolic activity did not depend on whether a rest or stress study was performed or on the change in visual score used to define 201Tl redistribution (0.25, 0.50, 0.75, and 1.00). CONCLUSIONS: In CAD patients, PET identifies glucose metabolic activity in the majority of fixed 24-hour 201Tl defects. However, very severe (near-complete) 24-hour 201Tl defects are less likely to exhibit metabolic activity on PET imaging than are defects with less-pronounced reductions in segmental 201Tl activity.

Coronary Angiography↗
PubMed1985

Insulin receptor down-regulation is linked to an insulin-induced postreceptor defect in the glucose transport system in rat adipocytes.

We have examined the relationship between insulin-induced receptor downregulation and the induction of a postreceptor defect in the insulin-stimulated glucose transport system in rat adipocytes, and found that downregulation was linked to the expression of the postreceptor defect. When recycling of insulin receptors was inhibited by 20 mM Tris, insulin pretreatment (100 ng/ml) for 4 h at 37 degrees C induced both net loss (65%) of cell-surface receptors and a 63% decrease in maximal insulin responsiveness. In contrast, when cells were treated with insulin alone for 4 h at 37 degrees C so that receptors could recycle, or treated at 16 degrees C with Tris plus insulin to inhibit receptor internalization, neither receptor downregulation nor a postreceptor defect was observed. Induction of the postreceptor defect was specific for insulin under conditions when downregulation would occur, since treatment of cells with Tris and the insulin mimicker spermine did not result in receptor loss or the postreceptor defect. Other experiments revealed that receptor downregulation occurred first without loss of insulin responsiveness, but, once the postreceptor defect appeared, its severity was correlated to the degree of further receptor loss, as a function of insulin dose and exposure time. Tris (20 mM) alone acutely decreased maximally stimulated glucose transport rates slightly (22%), but this effect was rapidly reversible after Tris removal and could not have been directly responsible for the lasting and profound postreceptor defect seen after pretreatment with insulin plus Tris. Taken together, these data suggest that insulin-induced receptor loss is linked to the induction of the postreceptor defect. The postreceptor defect was due to an inability to maximally increase the maximum velocity of glucose transport. Furthermore, the expression of the postreceptor defect depended upon the extent to which the glucose transport system was allowed to deactivate; maintaining the glucose transport system in an activated state prevented its expression. Thus, the mechanism could involve rapid inactivation or sequestration of glucose transporters during deactivation such that they become refractory to the subsequent stimulatory effects of insulin. In conclusion, (a) insulin does not acutely induce a postreceptor defect in the glucose transport system of adipocytes without loss of cell-surface insulin receptors; (b) the defect in stimulated glucose transport has been induced distal to the insulin receptor via a mechanism linked to receptor loss; and (c) the postreceptor lesion is due to decreased number of intrinsic activity of glucose transporters on the cell-surface in the presence of a maximally effective insulin concentration. These data suggest that insulin receptor downregulation and postreceptor defects in insulin action, which frequently co-exist both in vivo and in vitro, may be linked mechanistically.

Adipose Tissue↗
PubMed1981

Evaluation of durapatite ceramic as an alloplastic implant in periodontal osseous defects. I. Initial six-month results.

Eight patients received a new polycrystalline ceramic form of pure hydroxylapatite (Durapatite) as a bone implant material in various types of infrabony defects following internally beveled full thickness flaps, root planing, and defect debridement. All osseous margins and defects were measured from the CEJ using a standardized periodontal probe. Similarly debrided defects that were not implanted served as controls. Defect selection as either experimental or control site was based on either split-mouth or alternating defects design. Periodontal dressing and systemic tetracycline were used for 10 days. Results for documentation and plaque control were at 10, 20, and 30 days, and 3 and 6 months. Measurements relating to defect changes were made at the 6-months surgical re-entry. For evaluation purposes original defect depths were divided into three groups. In Group I (less than 3 mm) defect fill was 1.2 mm (60%) for the implanted defects and 0.6 mm (40.5%) for the control sites (significantly different at P less than 0.05). In Group II (3--6 mm) defect fill of 1.7 mm (48.5%) for implanted sites was significantly better than the 0.1 mm (11.1%) for the control sites. In the deepest group (Group III greater than or equal to 6 mm) Durapatite placement yielded 2.6 mm (39.9%) of defect fill while debridement alone resulted in 1.3 mm (14.8%) of fill. Hard tissue changes demonstrated a substantial advantage for use of Durapatite over controls, while soft tissue changes were similar for both. The clinical impression at re-entry and the numerical data indicate that pure hydroxylapatite ceramic has a definite potential as an alloplastic implant in the treatment of periodontal osseous defects.

Adult↗
PubMed1986

Clinical and volumetric analysis of three-wall intrabony defects following open flap debridement.

Fourteen defects were treated with flap debridement procedures using the Prichard principle of epithelial exclusion. Six defects were considered to be medium in width (3-4 mm), seven defects were wide (greater than 4 mm), and one defect was narrow (1-2 mm). The parameters studied were changes in gingival and plaque scores, attachment levels, and bone scores. All defects were reentered 9 to 16 months after surgery and changes between the pretreatment and posttreatment bone levels were recorded. The mean gain in probing attachment level was 2.76 mm. The mean amount of defect fill measured from models was 2.56 mm, while the mean defect fill from direct measurements was 3.26 mm. The percentage defect fill measured from study models was 61%. Crestal resorption was 9.7%. The average change in defect volume unadjusted for crestal resorption was 61.8 cu mm. Seven defects had a 50% or greater decrease in defect volume, while seven defects had less than a 50% change. Intrabony defects where calculus is present on the involved tooth surface prior to therapy will repair with substantial amounts of bone as a result of open debridement.

Alveolar Process↗
PubMed2001

A comparative study utilizing open flap debridement with and without enamel matrix derivative in the treatment of periodontal intrabony defects: a 12-month re-entry study.

BACKGROUND: Previous studies have demonstrated that enamel matrix derivative (EMD) has the ability to improve clinical parameters when used to treat intraosseous defects. The purpose of the present study was to compare at 12 months postsurgery sites treated with open flap debridement (OFD) alone to those treated with OFD and EMD. METHODS: Twenty-three subjects with at least 2 intrabony defects were chosen. Fifty-three defects received EMD in conjunction with OFD. Thirty-one defects in these same 23 subjects were treated with OFD alone. Stents were fabricated to serve as fixed reference points. Re-entries were performed at least 1 year after initial surgery. Soft tissue measurements were recorded prior to initial surgery and prior to re-entry for gingival (GI) and plaque (PI) indices, probing depth (PD), gingival margin position, and clinical attachment level (CAL). Hard tissue measurements were recorded during the initial and re-entry surgery for level of crestal bone and depth of defect. Statistical analysis was conducted using the method of generalized estimating equations to determine changes in GI, PI, PD, CAL, fill of the osseous defect, and crestal resorption. Percent of defect fill was also calculated. RESULTS: In all categories, treatment with EMD (test) was superior to treatment without EMD (control). Average PI and GI were not significantly different either initially or prior to re-entry. The average PD reduction was 2.7 mm greater with EMD than controls. The average CAL gains were 1.5 mm greater, and the average fill of osseous defect 2.4 mm greater with EMD than controls. The average percent of defect fill after adjusting for crestal bone loss was more than 3 times greater for EMD versus control-treated sites (74% defect fill with EMD versus 23% defect fill for control sites). CONCLUSIONS: This study indicates that treatment of periodontal intraosseous defects with EMD is clinically superior to treatment without EMD (open flap debridement) in every parameter evaluated. Re-entry data demonstrate that percent fill of osseous defects treated with EMD compares favorably with the treatment results utilizing bone grafts or membrane barriers, according to published literature.

Adult↗
PubMed2003

Qualitative and quantitative expression of bovine bone mineral in experimental bone defects. Part 1: Description of a dog model and histological observations.

BACKGROUND: The purpose of this study was to evaluate histologically the contribution of inorganic bovine bone biomaterial in a new experimental bone defect in dogs at different healing periods and to examine newly formed bone around the grafted mineral particles and their relationship in membrane-protected (test) and non-protected intrabony (control) defects. METHODS: Four round intrabony defects, 5 x 4 mm were made bilaterally (at different times) on the lateral bony mandibular angle in eight dogs. Two defects were filled with bovine bone mineral (BBM) particles and two remained non-grafted but were blood clotted. A collagen membrane covered each defect type (n = 4). This procedure was repeated on the contralateral side at a different given time to obtain two different healing periods in each dog. Thus, four specimens were obtained at 3, 6, 12, and 24 months postoperatively for each healing period. The non-decalcification method (Donath technique) with Stevenel's blue and van Gieson's picro fuchsin staining was used for histological examination. RESULTS: Newly formed bone was observed at all examined defect types. The BBM particles were clearly evident regardless of the healing period. At 3 and 6 months, newly formed bone, woven in nature, was incorporated with the grafted particles. High cellular bone with occasional osteoclasts was noted towards the surface of the mineral particles. No substantial difference was observed between the protected and the non-protected defects except for higher ossified centers around the membrane-protected defects. At the non-grafted sites, the membrane-protected defect showed newly formed bone near the bony walls, and particularly under the membrane, establishing a bony bridge over the defect at the healing periods. The non-grafted unprotected defect (control) showed bone formation only at the base and close to the bony walls leaving a healed concave configuration. At 1 and 2 years, the grafted sites showed full bone healing configuration. However, the grafted particles still dominated the previous defect area and were completely surrounded by the newly formed bone. Osteons and lamellar bone arrangement were established but the bone was still highly cellular and osteoclasts could still be identified. The non-grafted membrane-protected sites showed excellent bone healing although areas of non-mineralized soft tissue were often seen. The control sites healed but still presented with a concave surface configuration. CONCLUSIONS: BBM biomaterial is a highly osteoconductive material. In a 4-wall bony defect, newly formed bone was well evident in establishing excellent bone healing configuration with or without a regenerative biological barrier. The grafted material dominated the experimental sites with no substantial resorption at any healing period up to 2 years observation.

Alveolar Bone Loss↗
PubMed2006

Digital volume tomography in the diagnosis of peri-implant defects: an in vitro study on native pig mandibles.

BACKGROUND: The aim of this study of native pig mandibles was to investigate the accuracy and quality of the representation of peri-implant defects by intraoral radiography (IR), panoramic radiography (PR), computer tomography (CT), and digital volume tomography (DVT). METHODS: The examination was carried out on 19 native pig mandibles. In the toothless sections of the mandibles, one or two implants were inserted. Following the standardized preparation of peri-implant defects (11 each of dehiscences, fenestrations, and 2- to 3-walled intrabony defects), IR, PR, CT, and DVT were performed. The peri-implant defects were measured using appropriate software on the digitized IR and PR image programs. As a control method, the peri-implant bone defects were measured directly using a reflecting stereomicroscope with measuring ocular. The statistical comparison between the measurements of the radiographic scans and those of the direct readings of the peri-implant defects was performed with Pearson's correlation coefficient. The quality of the radiographic scans was determined through the subjective perception and detectability of the peri-implant defects by five independent observers. RESULTS: In the DVT and CT scans, it was possible to measure all the bone defects in three planes. Comparison with the direct peri-implant defect measurements yielded a mean deviation of 0.17+/-0.11 mm for the DVT scans and 0.18+/-0.12 mm for the CT scans. On the IR and PR images, the defects could be detected only in the mesio-distal and cranio-caudal planes. In comparison with the direct measurements of the peri-implant defects, the IR images revealed a mean deviation of 0.34+/-0.30 mm, and the PR images revealed a mean deviation of 0.41+/-0.35 mm. The quality rating of the radiographic images was highest for the DVT scans. CONCLUSIONS: Overall, the CT and DVT scans displayed only a slight deviation in the extent of the peri-implant defects. Both radiographic imaging techniques permitted imaging of peri-implant defects in three planes, true to scale, and without overlay or distortion. The DVT scans showed the best imaging quality.

Alveolar Bone Loss↗
PubMed2007

Surgical treatment of infrabony defects with autologous platelet concentrate or bioabsorbable barrier membrane: a prospective case series.

BACKGROUND: Autologous platelet concentrate (APC) contains concentrated platelet-derived growth factors that promote wound healing and tissue regeneration. The purpose of this prospective case series was to compare the treatment effects of an intralesional graft of APC to guided periodontal regeneration (GPR) using a bioabsorbable barrier membrane (MEM) over a 52-week period. METHODS: Five patients were recruited for the study from two private periodontal practices. There were four females and one male having a mean age of 33 +/- 10.23 years. The five selected contralateral teeth had similar, but not identical, combinations of 1-, 2-, and 3-wall infrabony defects not involving furcations. Probing depths (PDs) of the defects were > or = 6 mm and had radiographic angular infrabony defects > or = 4 mm in depth. The patients had no local or systemic contraindications to minor oral surgical procedures and had not taken systemic antibiotics for > or = 6 months before the commencement of the study. All patients had completed cause-related periodontal therapy up to 6 months previously and had achieved a satisfactory level of oral hygiene. The selected teeth did not have purulent discharge from the pockets and responded normally to pulp sensibility testing. Patients were excluded if they smoked, were pregnant or lactating, or were allergic to any of the materials to be used in the treatment. At baseline and 8, 26, and 52 weeks after surgery, PDs, recession (REC), presence of plaque, and bleeding on probing were recorded, and standardized periapical radiographs were taken. At the time of surgery, the vertical distance to the deepest point of the infrabony defect was measured from the cemento-enamel junction (CEJ) to the buccal and lingual bone crests. The vertical distance to the base of the defect from the CEJ and defect angles were obtained from radiographs. The paired contralateral infrabony defects were treated with a graft APC or MEM after debridement and EDTA root surface conditioning. Surgical flaps were prepared and closed according to the papilla preservation method. Post-surgical care was provided at 1, 2, 8, 26, and 52 weeks after surgery. A mouthwash of 0.2% chlorhexidine gluconate was used twice daily for the first 3 weeks after surgery. Mean PD, REC, clinical attachment level (CAL), radiographic bone loss, and defect angle were computed and compared for each data collection point. RESULTS: From baseline to 52 weeks, a mean PD reduction of 3 +/- 1.41 mm (APC) and 3.6 +/- 1.67 mm (MEM), mean REC increase of 0.8 +/- 1.01 mm (APC) and 0.6 +/- 1.14 mm (MEM), mean CAL gain of 2.2 +/- 1.79 mm (APC) and 3 +/- 1 mm (MEM), mean radiographic bone fill of 3.24 +/- 2.85 mm (APC) and 2.7 +/- 1.9 mm (MEM), and mean defect-angle increase of 15.25 degrees +/- 18.21 degrees (APC) and 22.4 degrees +/- 27.3 degrees (MEM) were calculated. CAL gain was not related clearly to defect angle at baseline, although radiographic bone fill was slightly greater for defect angles <39.4 degrees +/- 7.88 degrees. CONCLUSIONS: This case series of five similar, but not identical, bilateral paired infrabony defects suggests that an APC graft achieves a similar CAL gain and PD reduction to GPR using an MEM over a 52-week period. A larger, controlled clinical trial is needed to evaluate further the efficacy of autologous platelet-rich plasma for the treatment of infrabony defects.

Absorbable Implants↗