Biomedical subjects

Avital Kozlovsky

Publications and source records attributed to Avital Kozlovsky.

12 recordsLinked to original sources

PubMed2006

The influence of inflammation on the polarization colors of collagen fibers in the wall of odontogenic keratocyst.

Epithelial-mesenchymal interactions have been found to play a role in the pathogenesis of odontogenic keratocyst (OKC). In the present study we investigated the effect of inflammation in the OKC wall on the polarization colors of Picrosirius red-stained collagen fibers. 50 cases of OKC were selected and separated into two groups according to the inflammatory intensity: those with mild-to-moderate inflammation (Group A), and those with intense inflammation (Group B). The polarization colors of the collagen fibers were recorded separately for thick and thin fibers. Polarization colors of the thin fibers were in the green- to yellow spectrum, without significant differences between the groups. However, polarization colors of the thick fibers significantly differ between the groups. In Group B, the frequency of thick fibers with green birefringence decreased significantly, whereas fibers with red polarization colors increased in frequency (4.6% and 44%, respectively) compared with Group A (12.3% and 23.6%, respectively). It can than be concluded that inflammation has an impact on the packing of collagen fibers in the connective tissue wall of OKC as reflected by their birefringence colors under polarized light. In the presence of dense inflammation, the percentage of thick fibers with green birefringence decreases, with an increase in thick fibers with red birefringence which appeared more packed.

Azo Compounds↗

PubMed2006

A distinguishable observation between survival and success rate outcome of hydroxyapatite-coated implants in 5-10 years in function.

PURPOSE: To differentiate between the survival and success definitions of functional hydroxyapatite (HA)-coated implant prosthesis. METHODS: A total of 248 implants (62 patients), 5-10 years in function, were evaluated. The implant distribution length was 8 mm (6.5%), 10 mm (29.4%), 13 mm (30.2%) and 15 mm (33.9%). The diameter was 3.25 mm (60.1%) and 4 mm (39.9%). Probing depth (PD), gingival index (GI), height of keratinized mucosa (KM) and recession (REC) were measured. Periapical radiographs were taken to estimate the amount of crestal bone resorption (BL), mesially and distally, with the aid of a millimetric-scaled magnifying glass (x 8). Only implants that fulfilled the success rate criteria were considered as successful. All other functional implants were assigned to the non-successful group. All functional implant prostheses were defined as survival ones. RESULTS: The accumulative survival rate after 5 and 10 years was 94.4% and 92.8%, respectively. Accumulative success rates were 89.9% and 54%, respectively. Implants 13 and 15 mm in length (97.9% and 96.4%, respectively) had the highest survival rate, which was higher over implants 8 and 10 mm in length (75%, P<0.01 and 88.2%, respectively). The survival rate of 4 mm diameter implants compared with 3.25 mm was 96.5% and 90.3%, respectively (P=0.019). The average BL was 1.7, 0.92 and 2.79 mm for the survival, successful and non-successful defined implant groups. PD was 3.26, 2.79 and 4 mm and GI was 0.96, 0.75 and 1.57, respectively. These measurements were statistically different between implant groups. KM and REC measurements showed similar scoring for all groups. A correlation was shown between successful and non-successful implants on the score of GI and PD (P<0.001 in both). CONCLUSION: A distinguishable observation between survival and success rate was noted particularly in long-term observations. Implant length and diameter have an influence on the survival rate. Clinical parameter scores expressed an influence on the defined implant status.

Adult↗

PubMed2006

Comparative study of two root coverage procedures: a 24-month follow-up multicenter study.

BACKGROUND: Treatment alternatives to cover exposed root surfaces include free grafts, pedicle flaps, and barrier membranes. This 24-month follow-up study clinically evaluated the long-term effect of a coronally advanced flap procedure with the additional use of enamel matrix derivative (EMD) to treat gingival recession versus the subpedicle connective tissue graft (CTG) procedure. METHODS: Miller Class I or II buccal recession-type defects in the anterior teeth or premolars in 65 patients (28 in EMD and 37 in CTG groups) were treated in several centers. At baseline and 12 and 24 months post-treatment, vertical recession defect (VRD), height of keratinized tissue (HKT), and probing depth (PD) were recorded, and the percentage of root coverage (PRC) of the original defect was calculated. Student t test, analysis of variance, and analysis of covariance were used for statistical analyses. RESULTS: At 12- and 24-month evaluations, PRC was 73.2% (SD=15.58%) and 76.9% (SD=16.77%) in the EMD group and 86.8% (SD=12.48%) and 84.3% (SD=13.32%) in the CTG group, respectively (P<0.001). Differences between groups were statistically significant (P=0.002). Baseline HKT was 1.07 mm (SD=0.66 mm) in the EMD group and 1.65 mm (SD=0.92 mm) in the CTG group. At 12 and 24 months, values were 1.75 mm (SD=0.59 mm) and 2.25 mm (SD=0.52 mm) in the EMD group and 4.24 mm (SD=0.89 mm) and 4.05 mm (SD=0.94 mm) in the CTG group, respectively. Differences in HKT were statistically significant within (EMD: P<0.001; CTG: P=0.017) and between (P<0.001) groups. CONCLUSIONS: Both treatments proved clinically successful. CTG treatment showed a higher percentage of root coverage and HKT increase. EMD is a valuable, long-term effective treatment alternative to achieve root coverage together with an increase in HKT.

Adolescent↗

PubMed2006

Interaction of chlorhexidine with smooth and rough types of titanium surfaces.

BACKGROUND: Chlorhexidine (CHX) digluconate exerts plaque inhibitory efficacy in the natural dentition environment due to a superior degree of persistence at the tooth surface. The purpose of the present study was to assess the interaction of CHX with titanium surfaces to estimate its antiplaque potential in the peri-implant environment. METHODS: Saliva-coated machined smooth (S) and sand-blasted acid-etched rough (R) titanium disks were soaked in either 0.1% or 0.2% CHX solution. After 24 hours, CHX amounts that were adsorbed, washed out, and desorbed from the titanium surfaces were determined spectrophotometrically at 230 nm. The antibacterial activity of CHX-treated titanium disks was assessed by measuring bacterial inhibition zones on Streptococcus mutans lawns. RESULTS: Titanium disks adsorbed 3% to 8% of the available CHX, which was significantly higher with 0.2% CHX (P<0.001) than with 0.1% CHX and two-fold higher on the R titanium disks compared to S titanium surface (P<0.001). After rinsing with water, 2.2% of the adsorbed CHX was washed out. Over 24 hours, S- and R-type disks released 1.1% and 0.6% of the adsorbed agent, respectively. Larger bacterial inhibition zones were obtained with 0.2% CHX and in R disks compared to S disks. CONCLUSIONS: CHX displayed persistence at the titanium surface. The adsorption level and bacterial growth inhibition were affected by CHX concentration and titanium surface characteristics, with higher levels of adsorption and antibacterial activity with 0.2% CHX and rough titanium surface. The slow CHX release rate suggests persistence of this agent at the titanium-pellicle surface, which can provide a long-term antiplaque effect.

Adsorption↗

PubMed2006

Experimental intrabony and periodontal defects treated with natural mineral combined with a synthetic cell-binding Peptide in the canine: morphometric evaluations.

BACKGROUND: A synthetic peptide (P-15) analog of collagen added to anorganic bovine bone mineral (ABM) has recently been used as an enhanced bone graft material (ABM/P-15). The objective of this study was to test the contribution of ABM/P-15 in a new putty form (PEP) in two experimental membrane-protected defects: periodontal and intrabony. Its efficacy as filler biomaterial in guided tissue regeneration (GTR) and guided bone regeneration (GBR) procedures was evaluated histologically and morphometrically. METHODS: In the maxillary canines, a facial mucoperiosteal flap was raised bilaterally in nine dogs. Two circular defects, 5 mm in diameter and 2 mm in depth, were made on each side: a fenestrated periodontal on the canine root and an intrabony in the alveolar diastema, anteriorly. PEP particles filled both defects on one side; the contralateral side was blood filled (control). All surgical sites were covered with a bioabsorbable membrane. Histologically, at 4 months, tissue blocks were made using the cutting/grinding non-decalcification method followed by morphometric analysis. In the periodontal fenestration root surface, the linear percentage of new cementum (%CEM), area percentage of new bone (%NB), and residual biomaterial particles (%PEP) were calculated. These same measurements were calculated at the intrabony sites, except cementum. The amount of direct NB to PEP contact was measured to assess the osteoconductivity level (OSC). The Pearson correlation test was used to evaluate any significant relationship between the different measured parameters. RESULTS: In the grafted and non-grafted fenestration root surface defects, %CEM averaged 59.5% and 73.9% (P <0.02), respectively; %NB averaged 36.1% and 31.4%, respectively; and %PEP averaged 20.6%. The mean percentage of OSC was 52.4%. In the intrabony grafted and non-grafted sites, %NB averaged 50.7% and 60.1%, respectively (P <0.02). Residual %PEP averaged 26.1%, and OSC averaged 35.6%. At the intrabony sites, higher %NB and lower %OSC were found compared to the fenestration sites (P <0.001 and P <0.03, respectively). Correlation analysis showed a negative correlation between %NB and %PEP at the fenestration defects. In between the two defect types, %OSC was significantly correlated (P <0.05). CONCLUSIONS: ABM/P-15 putty showed osteoconductive and biocompatible qualities. However, at 4 months in this model, no enhanced regeneration was present compared to a higher CEM and NB growth detected at non-grafted membrane-protected sites.

Absorbable Implants↗

PubMed2005

The amount of newly formed bone in sinus grafting procedures depends on tissue depth as well as the type and residual amount of the grafted material.

OBJECTIVES: Bone replacement substitutes are almost unavoidable in augmentation procedures such as sinus grafting. The objective of the present study was to evaluate the osteoconductive capability of two different scaffold fillers in inducing newly formed bone in this procedure. MATERIAL AND METHODS: Sinus floor augmentation and implant placement were carried out bilaterally in 12 patients. Bovine bone mineral (BBM) was grafted on one side and beta-tricalcium phosphate (beta-TCP) on the contralateral side. Both were mixed (1:1 ratio) with autogenous cortical bone chips harvested from the mandible by a scraper. Hard tissue specimen cores were retrieved from the augmented sites (at the previous window area) at 12 months. Decalcified sections were stained with haematoxylin-eosin and the fraction area of new bone and filler particles was measured. In addition to the effect of the filler on new bone formation, the latter was tested to determine whether it correlated with the tissue depth and residual amount of the grafted material. RESULTS: Bone area fraction increased significantly from peripheral to deeper areas at both grafted sites in all cores: from 26.0% to 37.7% at the beta-TCP sites and from 33.5% to 53.7% at the BBM-grafted sites. At each depth the amount of new bone in BBM sites was significantly greater than that in TCP sites. However, the average area fraction of grafted material particles was similar in both fillers and all depth levels (beta-TCP=27.9-23.2% and BBM=29.2-22.6%, NS). A significant negative correlation was found between bone area fraction and particle area fraction at the middle (p=0.009) and deep (p=0.014) depths in the beta-TCP sites, but not at the BBM sites. CONCLUSION: At 12 months post-augmentation, the two examined bone fillers, beta-TCP and BBM, promoted new bone formation in sinus grafting but the amount of newly formed bone was significantly greater in BBM-grafted sites. However, both exhibited similar residual grafted material area fraction at this healing period. This could imply that BBM possesses better osteoconductive properties.

Adult↗

PubMed2005

Effect of air-polishing devices on the gingiva: histologic study in the canine.

OBJECTIVES: The aim of this study was to evaluate histologically the immediate effect of two types of air-polishing devices (APDs) on the gingiva. MATERIAL AND METHODS: The buccal gingiva in four mongrel dogs was exposed to 5, 10 and 20 s of instrumentation, applying a hand-piece type of APD (HP-APD) PROPHYflex and a stand-alone type of APD (SA-APD) Jetpolisher in a split-mouth design. Immediately after treatment, the exposed gingiva was excised by sharp dissection and fixed in 10% buffered formalin. For each specimen, 15 sections, 20 microm apart, corresponding to the central part of the treated and control untreated gingiva were cut and stained with haematoxylin and eosin. Stained sections were examined histomorphometrically for keratin width and epithelial cell layer (ECL) (prickle and basal cell layers) width. Extent of erosion was expressed as loss of keratin and ECL compared with control. RESULTS: Microscopic examination presented changes in keratin and ECL, including keratin detachment and disruption of the normal ECL architecture. The erosive changes in the gingiva caused by both APD, positively correlated with instrumentation time (p<0.001) and type of instrument (p=0.008). Keratin loss was significantly higher for SA APD than for the HP APD in each time interval (p=0.019). Following exposure for 5 s, both APD caused a 25% loss of the ECL. Exposure for 10 and 20 s revealed a significantly greater ECL loss caused by the SA-APD than the HP-APD (p=0.018). Exposure for 20 s was the only time interval that presented the area of total epithelium erosion with SA-APD causing significantly more (p=0.002) areas of total epithelial erosion than the HP-APD. CONCLUSION: Gingiva exposure to air-polishing slurry delivered by APD caused localized trauma because of epithelial erosive changes with severity, positively correlated with instrumentation time and design principles of the applied APD. The clinician should be aware of the potential insult of the gingiva when applying the APD and careful precautions should be taken.

Animals↗

PubMed2005

Guided periodontal regeneration using bilayered collagen membranes and bovine bone mineral in fenestration defects in the canine.

This study was performed to evaluate the effect of deproteinized bovine porous bone mineral (BBM) and BBM-collagen (BBMC) used alone or in combination with a bilayer collagen membrane in guided periodontal regeneration. In 12 dogs, contralateral surgical circular fenestration defects 5 mm in diameter were produced at the midbuccal aspect of the alveolar bone in 24 maxillary canines. Bone, periodontal ligament, and cementum were completely removed. Experimental sites were filled with BBM or BBMC. Bilayered collagen membranes covered half the experimental sites (BBM+M and BBMC+M), and the other half were left uncovered. Control sites remained empty; half were covered with collagen membranes (cont+M) and the underlying space spontaneously filled with blood, and half were left uncovered (cont). Three months postsurgery, undecalcified sections were prepared. Measurements were made using a caliper on a projection microscope, and the surface area of new bone and BBM particles within the healed surgical defect was evaluated using the point-counting method. In the experimental defects, new cementum covered 31% to 67% of the exposed dentin, with a significant difference between defects covered with membranes and defects that were not covered (P < .05). New cementum in the control (unfilled) defects also differed significantly between covered and uncovered defects. New bone growth presented a pattern similar to the cementum. There was no statistical difference between defects treated with BBM and BBMC, within both covered and uncovered groups. There was less connective tissue in the covered defects than in the uncovered defects (P < .05). The defects were filled with new bone, new connective tissue/bone marrow, and bovine bone particles. New bone area fraction was 23.4% to 25.2% in defects filled with BBMC and BBM, respectively (P = NS). Bone fraction area in membrane-covered defects ranged from 34.4% to 36.8% in experimental defects (P = NS). All membrane-treated defects showed higher values for bone area fraction in comparison to the uncovered control defects. Particle area fraction ranged between 17.4% and 26.2%, with only BBMC and BBM+M defects showing a statistically significant difference (P < .05). Defects filled with submembranous blood clot exhibited significantly more new cementum and bone regeneration than experimental defects filled with BBM or BBMC. Treatment of defects with BBM or BBMC showed similar influences on bone and cementum regeneration in fenestration periodontal defects. The presence or absence of bilayered collagen membranes was the predominant factor influencing bone and cementum regeneration.

Absorbable Implants↗

PubMed2004

A high molecular mass cranberry constituent reduces mutans streptococci level in saliva and inhibits in vitro adhesion to hydroxyapatite.

Previous investigations showed that a high molecular mass, non-dialyzable material (NDM) from cranberries inhibits the adhesion of a number of bacterial species and prevents the co-aggregation of many oral bacterial pairs. In the present study we determined the effect of mouthwash supplemented with NDM on oral hygiene. Following 6 weeks of daily usage of cranberry-containing mouthwash by an experimental group (n = 29), we found that salivary mutans streptococci count as well as the total bacterial count were reduced significantly (ANOVA, P < 0.01) compared with those of the control (n = 30) using placebo mouthwash. No change in the plaque and gingival indices was observed. In vitro, the cranberry constituent inhibited the adhesion of Streptococcus sobrinus to saliva-coated hydroxyapatite. The data suggest that the ability to reduce mutans streptococci counts in vivo is due to the anti-adhesion activity of the cranberry constituent.

Adult↗

PubMed2004

A multicenter comparative study of two root coverage procedures: coronally advanced flap with addition of enamel matrix proteins and subpedicle connective tissue graft.

BACKGROUND: Free grafts, pedicle flaps, and barrier membranes have been used to cover exposed root surfaces. The aim of the present study was to evaluate the clinical efficacy of a coronally advanced flap procedure with the additional use of enamel matrix protein derivative (EMD) to treat gingival recession and to compare it to the subpedicle connective tissue graft procedure (CTG). METHODS: The study was conducted in six different periodontal clinics. Miller Class I or II buccal recession type defects in the anterior or premolar teeth were treated in 70 consecutive patients, 30 with EMD and 40 with CTG. At baseline and 6 and 12 months post-surgical treatment, vertical recession defect, defined as the distance from cemento-enamel junction to gingival margin; width of keratinized tissue; and probing depth were recorded and the percentage of coverage of the original defect was calculated. Statistical analyses consisted of t-test, analysis of variance, and analysis of covariance. RESULTS: At 6 months, percent of root coverage was 77.4% +/- 11.92% in EMD and 84.1% +/- 11.97% in CTG (statistically significant at P = 0.024). At 12 months, percent of root coverage in EMD was 71.7% +/- 16.14% and 87.0% +/- 12.22% in CTG; again, differences between groups were statistically significant (P < 0.001). Differences between the 6- and 12-month vertical recession defect and percent of root coverage recordings within each group were also statistically significant. CONCLUSIONS: The connective tissue graft procedure was superior to the coronally positioned flap with the addition of enamel matrix proteins derivative in percentage of coverage and increase in width of keratinized tissue. The EMD procedure is a predictable treatment for root coverage that is relatively easy to perform and presents low patient morbidity, and is appropriate especially where a substantial increase in the width of keratinized tissue is not of prime importance.

Adolescent↗

PubMed2003

Peripheral giant cell granuloma associated with dental implants.

BACKGROUND: Peripheral giant cell granuloma (PGCG) is a well-circumscribed lesion confined to the alveolar and gingival mucosa. PGCG is considered a reactive lesion caused by local irritation or trauma. The objectives of the present study were to evaluate the incidence of PGCG in peri-implant lesions submitted for histologic examination, to establish its correlation with implant failure, and to discuss its pathogenesis. METHODS: The study was conducted on 25 periimplant biopsy specimens submitted for histological examination between 1999 and 2001. Sections (5 microm) of paraffin embedded tissues were cut and stained with hematoxylin and eosin. RESULTS: From the 25 specimens, three (two males and one female, ranging in age from 31 to 69 years) were identified as peripheral giant cell granuloma. The posterior mandible was affected in two cases and the anterior maxilla in one. The clinical appearance was an exophytic mass with a bleeding surface. The time interval between implantation and lesion development was from several months to 6 years. Recurrence following curettage was found in all cases. The implants were stable; however, two were removed either because of bone loss around the implant or because of several recurrences. In all cases healing was uneventful. CONCLUSIONS: Peripheral giant cell granuloma can develop in association with dental implants. Clinically, the lesions are similar to the classical PGCG. In the present study, the precise incidence could not be concluded because of the small number of selected cases. Due to the aggressive nature of the lesion and the high recurrence rate, implants can fail unless the lesion is detected early and proper surgical removal is performed. Tissue removed from the peri-implant area should always be submitted for histologic examination for accurate diagnosis.

Adult↗

PubMedDate not supplied

Marginal bone loss pattern around hydroxyapatite-coated versus commercially pure titanium implants after up to 12 years of follow-up.

PURPOSE: The purpose of this study was to compare the marginal bone loss (MBL), complications, and 12-year survival rates of commercially pure titanium (cpTi) and hydroxyapatite (HA)-coated implants placed in the maxilla. MATERIALS AND METHODS: The study group consisted of 120 patients (77 women, 43 men) treated from 1988 to 1997. A total of 388 implants (156 cpTi and 232 HA-coated) were placed in the maxilla. There were 126 immediate (32.5%) and 262 (67.5%) nonimmediate implants. Patients were evaluated annually. Mean follow-up was 60 +/- 32.3 months. MBL was measured on radiographs using the implant threads as the dimensional reference. MBL, complications, and 12-year survival and success rates were correlated with implant coating, time of implantation, implant dimensions, and position in arch. RESULTS: Total mean MBL was 1.07 +/- 2.16 mm. MBL was significantly lower with cpTi implants (0.55 +/- 1.04 mm) compared to HA-coated implants (1.51 +/- 2.71 mm) (P < .001). No statistical difference in regard to MBL was found between immediate and nonimmediate implants (0.86 +/- 1.8 mm vs 1.16 +/- 2.3 mm). The total 12-year survival rate was 91.4%. HA-coated implants had a significantly higher 12-year survival rate than cpTi implants (93.2% vs 89%; P < .03). Nonimmediate implants had a significantly higher failure rate (8.2%) than the immediate implants (1.3%) (P < .009). No correlation was found between type of implant coating and late implant failure. DISCUSSION: Immediate implants can serve as a predictable option, providing higher survival and success rates. HA-coated implants tended to fail less during the surgical phase, but had higher mean MBL compared to cpTi implants. CONCLUSIONS: HA-coated implants had greater MBL than cpTi implants but a higher 12-year survival rate. Immediate implants had a lower failure rate than the nonimmediate implants in this study population.

Adolescent↗