Influence of operator skill level on the clinical outcome of non-surgical periodontal treatment: a retrospective study.

OBJECTIVES: The aim of this study is to evaluate the effect of operators experience and skill on treatment results of initial non-surgical periodontal therapy. MATERIALS AND METHODS: Initial periodontal treatment was carried out by either second-year periodontal residents (PR) or last year dental students (DS). From the treatment records of patients in each group, plaque and bleeding indices, and pocket depth (PD) at baseline and at re-evaluation were collected retrospectively on each tooth at six locations. Data were separated according to tooth type, area, and probing depth categories, sub-grouped to 1-3, 4-5, and ≥ 6 mm. RESULTS: Fifty and 49 records of DS and PR patients, accordingly, were analyzed. Initial periodontal treatment improved patient compliance in both groups and reduced signs of inflammation with significantly superior results in the PR group. Significant change in percentage of pockets was recorded in each category. The increase in percentage of sites with PD 1-3 mm and decrease in percentage of PD ≥ 6 mm pockets was significantly (p ≤ 0.001) superior in patients treated by PR. Percentage of 4-5 mm pockets was significantly reduced in both groups (p ≤ 0.01), with a significantly greater reduction in the mandibular molar and anterior teeth in the PR group. CONCLUSIONS: Experience and skill significantly affect the outcome of non-surgical periodontal therapy, with more positive improvement in patient compliance and clinical parameters when performed by a more qualified operator. CLINICAL RELEVANCE: Improvement of operator skills may decrease the number of residual pockets and increase patient compliance following non-surgical periodontal treatment.

Deproteinized bovine bone in association with guided tissue regeneration or enamel matrix derivatives procedures in aggressive periodontitis patients: a 1-year retrospective study.

OBJECTIVES: To retrospectively evaluate and compare two regenerative periodontal procedures in young individuals with aggressive periodontitis (AgP). METHODS: Thirty-two patients aged 14-25 years (mean ± SD 19.3 ± 5.7) were diagnosed as having AgP with multiple intra-bony defects (IBDs) and treated by one of two regenerative modalities of periodontal therapy: guided tissue regeneration (GTR) using deproteinized bone xenograft (DBX) particles and a resorbable membrane (the GTR group), or an application of enamel matrix derivatives (EMD) combined with DBX (the EMD/DBX group). Periodic monitoring of treated sites included recording of probing depth (PD), clinical attachment level (CAL) and gingival recession. Pre-treatment and 1-year post-operative findings were statistically analysed within and between groups. RESULTS: The PD and CAL values decreased significantly with time, but not those between study groups. The mean pre-treatment and 1-year post-treatment PDs of the IBDs of the GTR group (n = 16; sites = 67) were 8.93 ± 1.14 mm and 3.58 ± 0.50 mm, respectively, and the mean CALs were 9.03 ± 1.03 mm and 4.16 ± 0.53 mm respectively. The mean PDs of the EMD/DBX group (n = 16; sites = 73) were 8.77 ± 1.04 mm and 3.61 ± 0.36 mm, respectively, and the mean CALS were 8.79 ± 1.04 mm and 3.77 ± 0.22 mm respectively (p < 0.001 for all). CONCLUSION: Surgical treatment of AgP patients by either GTR or by application of EMD/DBX yielded similarly successful clinical results at 1-year post-treatment.

Histomorphometric analysis of maxillary sinus augmentation using an alloplast bone substitute.

PURPOSE: To evaluate the regenerative potential of a fully synthesized homogenous hydroxyapatite:ß-tricalcium phosphate 60:40 alloplast material in sinus lift procedures. MATERIALS AND METHODS: Hydroxyapatite:ß-tricalcium phosphate was used for sinus floor augmentation. After 9 months, 12 biopsies were taken from 12 patients. Routine histologic processing was performed and specimens were analyzed using a light microscope and a digital camera. RESULTS: Histologic evaluation showed 26.4% newly formed bone, 27.3% residual graft material, and 46.3% bone marrow. The osteoconductive index was 33.5%. CONCLUSIONS: Hydroxyapatite:ß-tricalcium phosphate 60:40 alloplast material was found to be biocompatible and osteoconductive in maxillary sinus augmentation procedures.

Antral computerized tomography pre-operative evaluation: relationship between mucosal thickening and maxillary sinus function.

OBJECTIVES: to assess the correlation between maxillary sinus inferior mucosal thickening and sinus outflow obstruction. MATERIAL AND METHODS: the study included 280 computerized tomography (CT) scans (560 maxillary sinuses). CT aimed to assess sinusitis; trauma to the face and intubated patients were excluded. Mucosal thickening was graded as < 5 mm (1), < 10 mm (2), < 15 mm (3), < 20 mm (4) and > 20 mm (5), and classified by appearance as normal, rounded, circumferential, irregular, or complete. Maxillary sinus outflow was classified as patent or obstructed. RESULTS: mucosal thickening was found in 36.1% of the maxillary sinuses, graded as 31.2% (1), 34.2% (2), 12.9% (3), 5.4% (4) and 16.3% (5), and classified as rounded (11.8%), irregular (10.4%), circumferential (8.8%) and complete (5.2%). Sinus outflow was obstructed in 15% of the scans. Mucosal thickening of < 5 mm (11.1%), < 10 mm (36.2%) and > 10 mm (74.3%) was associated with sinus obstruction (P<0.0001). Rounded (6.1%), circumferential (55.2%), irregular (38.8%) and complete (100%) mucosal appearances were associated with sinus obstruction (P<0.001). When statistically combined, a substantial risk for sinus obstruction was observed with irregular mucosal appearance of > 5 mm (56.5% for grade 2 up to 82.6% for grades 3-5) and circumferential appearance (21.4% for grade 1 up to 100% for grades 3-5). A low risk for obstruction was found with the rounded appearance (mean 6.1%). CONCLUSIONS: irregular (> 5 mm), circumferential and complete mucosal appearance are associated with an increased risk for sinus outflow obstruction and an ENT consultation is recommended. A rounded mucosal appearance of any grade is associated with a low risk for sinus obstruction. Routine CT scans, including the maxillary sinus ostium, are recommended.

Simultaneous versus two-stage implant placement and guided bone regeneration in the canine: histomorphometry at 8 and 16 months.

AIM: To compare the effect of timing of implant placement and guided bone regeneration (GBR) procedure on osseointegration and newly formed bone at 8 and 16 months. MATERIAL AND METHODS: In seven dogs, four different sites were bilaterally established: (1) an implant placed in a 6-month healed (6m-GBR) bovine bone mineral (BBM) grafted site; (2) a simultaneously placed implant with the grafted BBM (Si-GBR) followed by a membrane coverage; (3) an implant placed in a membrane-protected non-grafted defect; and (4) an implant placement in a naturally healed site (Cont). Histomorphometry was obtained at 8 and 16 months post-implant placement. Bone-implant contact (BIC), crestal bone resorption (CBR), vertical intra-bony (VIB) defect, bone (BAF) and particle (PAF) area fractions, and osteoconductivity (CON) levels were measured. RESULTS: In all sites, BIC ranged between 62% and 79% with no significant differences. PAF ranged from 17% to 27%, with no effect of time. At 8 and 16 months, BAF was significantly smaller at the Si-GBR site when compared with all other sites, CON was significantly greater at the 6m-GBR site, and CBR and VIB were significantly smaller at the 6m-GBR when compared with the Si-GBR sites. CONCLUSIONS: The simultaneous and delayed techniques both showed a similar osseointegration level over time. However, the staged approach showed enhanced newly formed bone, higher osteoconduction around the grafted mineral, less CBR, and smaller vertical bone defect over time compared with the combined approach.

Bio-degradation of a resorbable collagen membrane (Bio-Gide) applied in a double-layer technique in rats.

OBJECTIVE: The aim of this study was to evaluate histologically the bio-degradation of two layers of Bio-Gide((R)) (BG) membrane, as compared with that of a single layer. MATERIAL AND METHODS: Two circular calvarial bony defects, 5 mm in diameter, were made in 24 Wistar rats. BG membrane, labeled with biotin, was cut into 5-mm-diameter disks, and placed in defects either as a mono-layer membrane (MLM) or as a double-layer membrane (DLM). Rats were sacrificed after 4 or 9 weeks and histology was performed. Membranes were stained with horseradish peroxidase-conjugated streptavidin and aminoethyl carbazole as a substrate for detection of biotinylated collagen. The area of collagen and thickness of the residual membranes were measured by image analysis software. Statistical analysis was performed using the non-parametric Wilcoxon's signed-ranks test. RESULTS: At 4-week collagen area per measurement window within the DLM sites (0.09+/-0.05 mm(2)) was significantly greater (P<0.01) than that in the MLM sites (0.047+/-0.034 mm(2)). At 9 weeks, the collagen area was also greater in the DLM sites (0.037+/-0.026 mm(2)) compared with that of the MLM sites (0.025+/-0.016 mm(2)); however, this difference did not reach statistical significance. The rate of membrane degradation, calculated as percent membrane lost compared with baseline, was similar for the DLM and MLM at both time points ( approximately 60% at 4 weeks and approximately 80% at 9 weeks). In addition, the residual DLM thickness at 4 weeks (475.5+/-73.77 mum) was significantly (P<0.01) greater than that of MLM (262.38+/-48.01 mum). At 9 weeks, membrane thickness was also greater in the DLM sites (318.22+/-70.45 mum) compared with that of the MLM sites (183.32+/-26.72 mum); however, this difference did not reach statistical significance. The reduction in thickness between 4 and 9 weeks was 30% for MLM and 33% for DLM. DISCUSSION: The use of a double layer of BG membrane results in a barrier of increased collagen area and thickness, compared with application of a single layer.

Regeneration of the Periodontal Apparatus in Aggressive Periodontitis Patients.

The purpose of this study is to evaluate and compare, retrospectively, the outcome of two different periodontal regeneration procedures in patients suffering from aggressive periodontitis (AgP). Twenty-eight patients were diagnosed with AgP, suffering from several intra-bony defects (IBD); that were treated by one of two periodontal regeneration techniques randomly assigned to each patient: a. guided tissue regeneration (GTR) or b. an application of extracted enamel matrix derivatives (EMD) combined with demineralized bone xenograft particles (DBX). Probing pocket depth (PPD), clinical attachment level (CAL), and gingival recession were recorded. Pre-treatment and follow-up (up to 10 years from the surgery) recordings were analyzed statistically within and between groups. A significant reduction was shown at time on PPD and CAL values, however, not between subject groups. CAL values decreased in all sites. At the EMD group (44 sites), CAL gain was 1.92 mm (±1.68) from pre-treatment to follow-up (p < 0.001) and at the GTR group (12 sites) CAL gain of 2.27 (±1.82) mm. In conclusion, 1⁻10 years observations have shown that surgical treatment of AgP patients by either GTR or by application of EMD/DBX results in similar successful clinical results.

Cross-linked and non-cross-linked collagen barrier membranes disintegrate following surgical exposure to the oral environment: a histological study in the cat.

BACKGROUND: Early barrier membrane degradation may result in decreased bone formation in guided bone regeneration (GBR) procedures. The aim of this study was to evaluate the bio-degradation of cross-linked (CLM) and non-cross-linked (NCLM) collagen membranes experimentally exposed to the oral environment of study animals. METHODS: In eight cats, 48 surgical procedures were performed, three along each side of the palate: 24 full-thickness soft tissue perforations were made and 24 full-thickness mini-flaps were raised. CLM or NCLM discs were placed either under the perforations and peripheral mucosa and left exposed (experimental) or covered by the flaps (controls). The four treatment modalities were equally distributed among the eight animals. Block sections were retrieved at 7 and 28 days post-operatively, providing histological specimens (6 each) at 7 and 28 days for each treatment modality. RESULTS: Histological observation revealed that CLM and NCLM remained intact in the control sites during the 28 days. At 7 and 28 days, CLM appeared interrupted in three and two experimental sites, respectively, and were undetected in the remaining sites. NCLM were interrupted in two sites each at 7 and 28 days, and were undetected in the other sites. There was no statistical difference between control specimens and between CLM and NCLM of the different treatment modalities at 7 or 28 days. CONCLUSIONS: Both cross-linked and non-cross-linked membranes were resistant to tissue degradation and maintained continuity throughout the study. However, none of the membranes was resistant to degradation when exposed to the oral environment

Biodegradation of three different collagen membranes in the rat calvarium: a comparative study.

BACKGROUND: Collagen barrier membranes are commonly applied in periodontal and bone-regenerative procedures. Membranes differ in their resorption pattern following implantation, thus influencing clinical outcome. The purpose of this study was to quantitatively evaluate the biodegradation of three different commercially available collagen membranes. METHODS: Collagen membranes were cut into 5-mm-diameter disks and labeled with aminohexanoyl-biotin-N-hydroxy-succinimide ester. One membrane disk of each type (non-cross-linked [NCL], glutaraldehyde cross-linked [GCL], and ribose cross-linked [RCL]) was implanted on the calvaria of 20 Wistar rats. Block sections were retrieved after 2 days (baseline, two animals), 14 days (10 animals), or 28 days (eight animals). Decalcified histologic sections were stained with streptavidin horseradish peroxidase. Residual membrane thickness and area were measured. Statistical analysis consisted of analysis of variance (ANOVA) with repeated measures. RESULTS: Statistically significant differences in the amount of residual membrane material were recorded within each membrane (among different time points) and among different membranes at the same time points (P <0.001). At 28 days, the least amount of residual collagen area, expressed as the percentage of baseline, was observed in the NCL group (13.9% +/- 10.25%), followed by the GCL (24.7% +/- 35.11%) and RCL (91.3% +/- 10.35%) groups. Residual membrane thickness, expressed as the percentage of baseline thickness, presented a similar pattern (31% +/- 16.55%, 37% +/- 41.90%, and 94.1% +/- 12.22%, respectively). ANOVA with repeated measures showed a significant interaction between membranes and time (P <0.001). CONCLUSIONS: The tested membranes differed in their degradation patterns and collagen contents. Membranes should be chosen for each clinical case according to the desired biodegradation characteristics.

Histomorphometric evaluation of natural mineral combined with a synthetic cell-binding peptide (P-15) in critical-size defects in the rat calvaria.

PURPOSE: The objective of this study was to histomorphometrically evaluate the synthetic peptide analog P-15 bound to anorganic bovine mineral (Pepgen/P15) in critical-size defects in the rat calvaria. MATERIALS AND METHODS: A 5-mm-diameter critical-size defect was prepared in 48 rat skulls and divided into 4 equal groups: Pepgen/P15 particles covered by a membrane, Pepgen/P15 particles uncovered, nongrafted membrane-protected sites, and nongrafted uncovered control sites. At 12 weeks, histomorphometric measurements were made of the percentage area of newly formed bone and residual particles, the length of internal and external bone bridging, and linearly, the regenerated marginal and central total tissue augmentation height. RESULTS: Nongrafted, membrane-protected sites gained 60.6% of newly formed bone, followed by 50.6% and 44.2% (P < .05 versus membrane only) at the grafted covered and uncovered sites, respectively. All experimental sites contained significantly (P < .005) more bone than did control sites (19.9%). In both types of grafted sites, the percentage area of Pepgen/P15 particles was similar. Mean internal and external length of bone bridging at nongrafted membrane-protected sites (76.7% and 71.2%, respectively) was significantly greater (P < .005) than that of the grafted covered (43.95% and 51.8%, respectively), grafted uncovered (28.7% and 23.9%, respectively), and control (28% and 25.5%, respectively) groups, except for internal bone bridging in the grafted covered sites. Regenerated marginal and central augmentation heights (0.92 mm and 1.02 mm, respectively) were greatest in the grafted covered group, followed by the non-grafted membrane-protected (0.88 mm and 0.51 mm, respectively), and grafted uncovered (0.89 mm and 0.12 mm, respectively) groups, all of which were significantly greater (P < .001) than the control group (0.63 mm and 0.04 mm, respectively). CONCLUSION: While anorganic bovine mineral/cell-binding peptide contributes in volume, membrane application significantly increases the amount of bone regeneration.

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.

Bone-to-Implant Contact and New Bone Formation Within Human Freeze-Dried Bone Blocks Grafted Over Rabbit Calvaria.

PURPOSE: To assess the extent of osseointegration with rough-surface implants and new bone formation (NBF) within human freeze-dried bone blocks (h-FDB) grafted over rabbit calvaria. MATERIALS AND METHODS: A total of 18 rectangular h-FDB blocks were stabilized bilaterally to the calvaria of nine New Zealand rabbits by two mini titanium screws each. A total of 18 rough-surface implants (5.0 × 6.0-mm) were placed, 9 simultaneously (immediate placement [IP]) on one side and 9 at 3 months after block grafting (delayed placement [DP]) on the contralateral side. At 12 weeks after the second surgical procedure, block biopsies were harvested and processed for histologic analysis. Morphometric measurements consisted of bone-to-implant contact (BIC) and the extent of NBF from the calvarial surface and outward into the block. A paired t test was applied for statistical analysis. RESULTS: All h-FDB blocks were integrated, and the implants showed clinical stability. Histologically, the BIC was primarily between the apical end of the implants and the host rabbit calvaria. Bone growth between the implant threads was minimal and inconsistent among all animals. Morphometric measurements showed that the mean BIC of the IP and DP implants with the blocks was 10.50% ± 5.99% and 23.06% ± 9.58%, respectively (P < .001). NBF was observed primarily in the cancellous compartment of the block adjacent to the recipient calvarial bed. The extent of NBF into the block around the IP and DP implants was 9.95% ± 8.41% and 12.90% ± 11.07%, respectively (P = 0.2). CONCLUSION: In this model, a significantly lower BIC was demonstrated when implants were placed simultaneously with h-FDB block grafting compared to those placed in a two-stage mode. However, both techniques showed limited osseointegration.

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.

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.

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.

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.

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.

Collagen barrier membranes may accelerate bacterial growth in vitro: a potential clinical risk to regenerative procedures.

OBJECTIVES: Evaluate the antibacterial properties of three commercial collagen membranes for guided bone regeneration (GBR). METHOD AND MATERIALS: BioGide®, OsseoGuard®, and CopiOs® membranes were tested for antibacterial properties against Streptococcus sanguinis, Staphylococcus aureus, and Staphylococcus epidermidis using a direct contact test (DCT). Samples of each membrane, sized 5 × 2 mm, were fixed to the side wall of 6 wells in a 96-well microtiter plate. Bacterial suspension was placed on each sample. The plate was incubated at 37°C for 1 hour to allow suspension fluid evaporation. Fresh medium was added to each well and the plate was mixed. Non-contaminated membrane samples served as negative control. Bacterial growth was monitored spectrophotometrically at 650 nm for 24 hours. ANOVA and Tukey's comparison tests were used for the statistical analysis. RESULTS: The presence of the membrane samples did not disrupt bacterial growth. However, the presence of OsseoGuard membrane accelerated bacterial growth rate of S sanguinis and S epidermidis as compared to the other two membranes and control samples (P < .001), and of S aureus as compared to the control alone (P < .001). CONCLUSIONS: The tested collagen membranes have no antibacterial properties. However, OsseoGuard presents a significant bacterial growth enhancement effect with possible significant clinical implications on the success of regenerative procedures around teeth and implants.

The importance of histopathological diagnosis in the management of lesions presenting as peri-implantitis.

PURPOSE: This study is a histopathological analysis of lesions clinically diagnosed as peri-implantitis (PI). MATERIALS AND METHODS: This retrospective study included microscopic findings in 117 peri-implant biopsies from lesions presenting clinical and radiographic features of peri-implantitis. RESULTS: The study group included 117 biopsies, mean age 55.2 years; 60.9% of biopsies were from failing implants during explantation, the remaining from surviving implants. All cases showed microscopic evidence for inflammation; however, although 41% exhibited only nonspecific inflammation, 29.9% exhibited actinomyces-related inflammation, 18.8% pyogenic granuloma (PG), and 10.3% giant cell granuloma (GCG). Differences in implant failure rates between pathological diagnostic groups were not statistically significant. Lesions with simple inflammation could not be distinguished clinically or radiographically from the potentially destructive lesions. CONCLUSIONS: There were no clinical features which could distinguish PI with simple inflammation from potentially destructive lesions mimicking PI, such as GCG, PG, and actinomycosis. However, to control GCG and PG surgical procedures would be recommended, actinomycosis would indicate specific antibiotics, whereas in nonspecific inflammation, these measures may not be indicated. The results of the present study provide evidence for the importance of early microscopic examination of lesions presenting clinically as peri-implantitis, a step toward more accurate diagnosis and improved treatment of PI and lesions mimicking PI.

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.