Local antimicrobial therapy after initial periodontal treatment

AIM

The aim of this single-blind, randomized, parallel-designed clinical trial (RCT) was to evaluate the clinical and microbiological effects of three sustained-release biodegradable polymers delivered into periodontal pockets following initial periodontal therapy.

METHODS

Forty-seven patients (28 females and 19 males) with a mean age of 51 years (range 29-71) underwent a periodontal examination at baseline (i.e. Week 0) and after 18 weeks. This included the assessment of the Plaque Index (PlI), Bleeding on Probing (BOP), Pocket Probing Depths (PPD) and Probing Attachment Levels (PAL) at six sites per tooth. Two to 4 months prior to baseline, all subjects had received initial periodontal therapy including motivation, instruction in oral hygiene practices and full-mouth scaling and root planing. At the treatment appointment (i.e. Week 2), the patients were randomly assigned to receive either Atridox trade mark, Elyzol Dental Gel or PerioChip at all residual periodontal pockets with a probing depth >/= 5 mm and concomitant BOP. In accordance with the manufacturer's recommendations, Elyzol Dental Gel was applied for a second time 7 days later. In addition to the clinical evaluation, subgingival microbiological samples were collected prior to treatment (i.e. Week 2) and at Weeks 4 and 18. Analysis of variance/covariance was used to evaluate changes from baseline to Week 18 for the clinical parameters.

RESULTS

Between the baseline and 18-week examinations, subjects treated with Atridox showed a significantly greater gain in mean PAL of 0.33 mm +/- 0.09 (SD) than subjects treated with Elyzol Dental Gel [0.03 mm +/- 0.09 (SD)](p = 0.03). However, the gain in PAL of 0.16 mm +/- 0.10 (SD) found after PerioChip application did not differ significantly from that obtained following the application of Atridox(p = 0.27). Of the sites treated with Atridox, 42% gained >/= 1 mm PAL and 9% >/= 2 mm PAL as opposed to the sites treated with Elyzol Dental Gel, in which 34% gained >/= 1 mm PAL and 8% gained >/= 2 mm PAL. Of the sites treated with PerioChip, 36% gained >/= 1 mm and 6% gained >/= 2 mm PAL following a completed initial periodontal therapy.

CONCLUSIONS

The application of the three biodegradable sustained release devices tested following initial periodontal therapy resulted in a statistically significant gain in mean PAL for AtridoxTM and a significant reduction in PPD for all three devices during the study period. Furthermore, when sites treated with Atridox were compared with sites treated with Elyzol, a significant difference in mean PAL gain (0.3 mm) was observed.

Phylogenetic analysis of Prevotella nigrescens, Prevotella intermedia and Porphyromonas gingivalis clinical strains reveals a clear species clustering

Prevotella nigrescens, Prevotella intermedia and Porphyromonas gingivalis are oral pathogens from the family Bacteroidaceae, regularly isolated from cases of gingivitis and periodontitis. In this study, the phylogenetic variability of these three bacterial species was investigated by means of 16S rRNA (rrs) gene sequence comparisons of a set of epidemiologically and geographically diverse isolates. For each of the three species, the rrs gene sequences of 11 clinical isolates as well as the corresponding type strains was determined. Comparison of all rrs sequences obtained with those of closely related species revealed a clear clustering of species, with only a little intraspecies variability but a clear difference in the rrs gene with respect to the next related taxon. The results indicate that the three species form stable, homogeneous genetic groups, which favours an rrs-based species identification of these oral pathogens. This is especially useful given the 7% sequence divergence between Prevotella intermedia and Prevotella nigrescens, since phenotypic distinction between the two Prevotella species is inconsistent or involves techniques not applicable in routine identification.

Enamel matrix proteins in the regenerative therapy of deep intrabony defects

AIM

This prospective multicentre randomized controlled clinical trial was designed to compare the clinical outcomes of papilla preservation flap surgery with or without the application of enamel matrix proteins (EMD).

MATERIAL AND METHODS

172 patients with advanced chronic periodontitis were recruited in 12 centers in 7 countries. All patients had at least one intrabony defect of > or =3mm. Heavy smokers (> or =20 cigarettes/day) were excluded. The surgical procedures included access for root instrumentation using either the simplified or the modified papilla preservation flap in order to obtain optimal tissue adaptation and primary closure. After debridement, roots were conditioned for 2 min with a gel containing 24% EDTA. EMD was applied in the test subjects, and omitted in the controls. Postsurgically, a strict plaque control protocol was followed. At baseline and 1 year following the interventions, clinical attachment levels (CAL), pocket probing depths (PPD), recession (REC), full-mouth plaque scores and full-mouth bleeding scores were assessed. A total of 166 patients were available for the 1-year follow-up.

RESULTS

At baseline, 86 test and 86 control patients presented with similar subject and defect characteristics. On average, the test defects gained 3.1+/-1.5 mm of CAL, while the control defects yielded a significantly lower CAL gain of 2.5+/-1.5 mm. Pocket reduction was also significantly higher in the test group (3.9+/-1.7 mm) when compared to the controls (3.3+/-1.7 mm). A multivariate analysis indicated that the treatment, the clinical centers, cigarette smoking, baseline PPD, and defect corticalisation significantly influenced CAL gains. A frequency distribution analysis of the studied outcomes indicated that EMD increased the predictability of clinically significant results (CAL gains > or =4 mm) and decreased the probability of obtaining negligible or no gains in CAL (CAL gains <2 mm).

CONCLUSIONS

The results of this trial indicated that regenerative periodontal surgery with EMD offers an additional benefit in terms of CAL gains, PPD reductions and predictability of outcomes with respect to papilla preservation flaps alone.

Town and gown in America: some historical and institutional issues of the engaged university

The engaged university is a descriptive term for linking the different perspectives of university/community partnerships in higher education in the United States. While interest in this idea comes from recent events and processes, there is an historical background for university/community relations that offers important suggestions on the issue related to institutionalizing this concept. The history includes the original religious founding of US institutions, the establishment of the land-grant system of colleges, and the expansion of the mass education system in US universities. The development of community-based research disciplines, dating from the time of the settlement house movement in America, provides support for university/community collaboration. While some faculty and administrators support this idea, others are more critical and do not see it supporting the strategic interests of their institutions or disciplines. Comprehensively supporting the engaged university at an institutional level means changing the way the academy operates and including community concerns in research, teaching and administrative decisions. This article explores some of these issues and some possible solutions.

Diagnostic characteristics of clinical and microbiological tests for monitoring periodontal and peri-implant mucosal tissue conditions during supportive periodontal therapy (SPT)

The aim of this study was to evaluate a clinical and a microbiological test for monitoring tissue condition during supportive periodontal therapy (SPT) and to compare their diagnostic characteristics at implant and tooth sites. Twelve female (age: 37-72 years) and 7 male patients (age: 26-83 years) were evaluated in this study on the basis of availability to follow a rigid SPT program. Patients had received a complete periodontal examination at 1 and 5 years after implant placement. This included standardized radiographs obtained at implants and matching control teeth. One implant site and one tooth site per patient were followed during the last 2 years of the SPT program. At each recall visit microbiological samples were analyzed according to DNA/RNA analysis identifying periodontal pathogens (IAI Pado Test 4.5, Institute for Applied Immunology, Zuchwil, Switzerland). Presence or absence of bleeding on probing at these sites was also noted using a standardized probing force of 0.25 N (Audio Probe, ESRO, Thalwil ZH, Switzerland). The percentage number of recall visits with positive bacteriological test results and positive BOP scores were calculated. Disease progression at the sites was defined if the annual increase in probing depth was > or = 0.5 mm/year (2.5 mm in 5 years) or if the annual decrease in CADIA values (Computer Assisted Densitometric Image Analysis) was more than -0.7 per year (-3.5 in 5 years). Changes below these values were considered as negative test results indicating stability of the sites. The diagnostic characteristics (sensitivity, specificity, positive and negative predictive values) of BOP and microbiological tests alone or in combination were then calculated using two-by-two tables. By application of increasing thresholds of BOP frequencies set for definition of positive test outcome (BOP > or = 10% > or = 20% > or = 25% > or = 50% > or = 75% > or = 90% or the combined BOP > or = 75%, but DNA positive > or = 10%, > or = 25% > or = 34% > or = 50% > or = 67% > or = 90%) receiver operator characteristics curves (ROC) were constructed for teeth and implants. The areas under the ROC curves were calculated and compared by means of chi-square tests. The results indicated statistically significant better diagnostic characteristics of both tests at implants compared to teeth. The inclusion of an additional microbiological test significantly enhanced the diagnostic characteristics of BOP alone at teeth as well as at implants.

Clinical and radiographic evaluation, following delivery of fixed reconstructions, at GBR treated titanium fixtures

Conditions following incorporation of fixed reconstructions, at endosseous titanium implants augmented at local bony dehiscence and fenestration defects using a bioabsorbable Resolut membrane were studied in 7 patients. Fixture stability, radiographic marginal bone levels and peri-implant soft tissue status were evaluated at 21 membrane treated and 17 control fixtures (installed in regions of adequate bone volume), following a 2-year period of functional loading. Prosthetic reconstructions were removed and clinical examination and Periotest values revealed that all fixtures were stable. All peri-implant soft tissues were clinically healthy. The mean probing depths at buccal sites for fixtures with original dehiscence (n = 10) and fenestration (n = 11) defects were 1.6 +/- 0.7 mm and 1.2 +/- 0.4 mm respectively. The control fixture group had a mean buccal probing depth of 1.4 +/- 0.6 mm. At abutment connection radiograph membrane treated fixtures had significantly lower marginal bone levels than control fixtures, indicating that optimal bone regeneration was not achieved at all defects. Mean radiographic bone loss 23-27 months following delivery of fixed reconstructions for original dehiscence and fenestration defect fixtures was 0.7 +/- 0.8 mm and 0.8 +/- 0.6 mm respectively at mesial surfaces, and 0.8 +/- 0.7 mm and 0.6 +/- 0.5 mm at distal surfaces. In the control fixture group a mean loss of 0.7 +/- 0.5 mm at mesial surfaces and 0.5 +/- 0.4 mm at distal surfaces was found. Results showed no significant difference in the rate of bone loss following functional loading between membrane treated and control fixtures.

Root conditioning using EDTA gel as an adjunct to surgical therapy for the treatment of intraosseous periodontal defects

The aim of this clinical study was to compare the treatment outcome following root surface conditioning using an EDTA gel preparation in conjunction with surgical therapy with that following conventional flap surgery in periodontal intraosseous defects. 36 patients, each of them contributing one intraosseous defect > or =4 mm in depth participated. Defect sites had a probing pocket depth > or =5 mm and bled on probing following hygienic treatment phase. No furcation involvement or endodontic complications were present. In the EDTA group, 18 consecutive patients, defects were treated by root conditioning with EDTA gel for 3 minutes in combination with surgical therapy. In the control group, 18 patients, conventional flap surgery was performed without root conditioning. Chlorhexidine rinsings 0.2% were prescribed following surgery for 2-3 weeks with modified oral hygiene instruction. A strict recall program was implemented including professional prophylaxis and oral hygiene reinforcement every 4-6 weeks until 6-month re-evaluation. Baseline probing pocket depths and defect depths of 7.1+/-1.3 mm and 6.9+/-1.6 mm in the EDTA group and 7.6+/-1.9 mm and 6.6+/-1.7 mm, respectively, in the control group were measured. 6-month clinical results showed a significant probing attachment level gain of 1.8+/-1.5 mm and 1.0+/-1.7 mm in the EDTA and control groups respectively. A probing bone gain of 1.0+/-1.3 mm in the EDTA group was measured with a non-significant gain of 0.4+/-1.2 mm in the control group. Radiographic analysis confirmed these results. There were no statistically significant differences in treatment outcome between the group treated by root conditioning in combination with flap surgery and conventional flap surgery alone.

Guided tissue regeneration for the treatment of intraosseous defects using a biabsorbable membrane. A controlled clinical study

The aim of this controlled, clinical study was to evaluate guided tissue regeneration using a bioabsorbable membrane in periodontal intraosseous defects. Forty patients, each contributing one defect > or =4 mm in depth participated. The control group (18 individuals) received conventional flap therapy, while the test group (22 individuals) was treated using the bioabsorbable membrane, Guidor. Clinical assessments were made by one examiner, blinded with respect to treatment group, at baseline, 6 and 12 months following surgery. Baseline probing pocket depths of 7.7+/-1.4 mm in the membrane group and 7.6+/-1.9 mm in the control group were measured. Twelve month results showed a significant clinical attachment level gain in both control (1.1+/-1.8 mm), and membrane group (1.3+/-2.1 mm). Probing pocket depth reduction of 2.6+/-1.9 mm and 2.7+/-1.9 mm was observed in the respective groups. Bone sounding showed a non-significant gain of 0.4+/-1.8 mm and 0.6+/-1.4 mm at membrane and control sites, respectively. Radiographic evaluation confirmed these results. There were no significant differences found between treatment groups for any of the tested variables. Smoking had a negative effect on healing in both groups. In conclusion, clinical and radiographic results indicate that guided tissue regeneration using a bioabsorbable membrane at intraosseous defects did not predictably achieve greater clinical attachment level gain nor bone gain when compared to conventional flap therapy.

Guided bone regeneration in dental implant treatment using a bioabsorbable membrane

The aim of this study was to evaluate an osteopromotive technique, using a bioabsorbable membrane, for its ability to restitute bone over buccal fenestration and dehiscence defects following fixture installation. 11 patients requiring dental implant treatment and exhibiting sufficient vertical height of the maxilla and compromised bucco-palatal dimensions, as determined clinically and radiographically, were included in the study. 17 Brånemark titanium fixtures were placed with buccal defects which were augmented by a bioabsorbable membrane, Resolut. No complications were observed post-operatively. At 6-8 months, abutment connection was performed, and clinical evaluation of the healed defect area was made. The number of exposed buccal threads at fixture installation (median 8; range 2-19), and abutment connection (median 0; range 0-5), respectively, was compared. Out of the 17 fixtures; 14 exhibited complete coverage with bone, whereas 3 showed some remaining threads. A small punch biopsy taken at abutment connection in an area where the membrane had been placed showed a combination of dense connective tissue and bone. Radiographic evaluation of the marginal periimplant bone level is in progress and results to date show a median bone loss of 1.2 mm after a loading period of 4-6 months. Results show that fixture dehiscence and fenestrations, augmented with this bioabsorbable membrane, demonstrate a highly significant amount of new bone formation.

Periodontal probe precision using 4 different periodontal probes

The aim of this study was to compare the relative intra- and inter-examiner reproducibility of 4 different periodontal probes. (1) The Hu- Friedy LL 20 Probe, a manual probe. (2) The Vivacare TPS Probe, a plastic manual probe with a standardised pressure of 0.20 N. (3) The Vine Valley Probe, an electronic probe using a standardised pressure of 0.25 N. 4. The Peri Probe Comp, a computerised electronic probe with a controlled pressure of 0.45 N in 2 mm pockets to 0.25 N in 13 mm pockets. Duplicate probing measurements were taken by 2 examiners in 10 patients on 3 index teeth, 1 molar, 1 premolar and 1 incisor at 6 sites per tooth. Teeth were selected to incorporate both shallow (< 5 mm) and deeper (> or = 5 mm) periodontal sites. The order of probes and examiners were changed in a systematic manner and measurements were repeated 1 week later to avoid bias due to examiner memory. Results show that the manual probe had the lowest degree of variation, with a correlation coefficient of 0.83. The manual and Peri Probe Comp frequently recorded deeper probing pocket depths compared to the TPS and Vine Valley probes. The results may have been influenced by the lack of familiarity with the automated probes.

The physician's role in covering deviance: assisting the physically handicapped

Responses of 18 physicians in 9 specialties show they devote considerable time during treatment of patients with physical disabilities on procedures for concealment.