Low Level Laser Therapy With an 810-nm Diode Laser Affects the Proliferation and Differentiation of Premature Osteoblasts and Human Gingival Fibroblasts In Vitro

Introduction: Photomodulation is a promising strategy for optimizing tissue healing, but its photomodulatory effects on the synergistic cellular metabolism of gingival and bony tissues remain largely unknown. The aim of the present study was to evaluate the photomodulatory effects of a diode laser (810 nm) on osteoblasts, HGFs and their co-cultures in vitro. Methods: Primary cultures of HGFs, cultures of immature osteoblastic cells (MG63) and their co-cultures were irradiated with a diode laser (810 nm), 15 J/cm². Cell cultures were examined for cellular proliferation (MTT assay), viability (FDA/PI staining) after 24, 48 and 72 hours and cell differentiation (qPCR of collagen type 1a - COL1a and alkaline phosphatase expressions - ALP) after 7 days. Results: Photomodulation with an 810-nm diode laser increased cell proliferation at all time points. COL1a gene expression increased both in HGF and co-cultures. ALP expression was up-regulated in osteoblastic cultures, but co-cultures with fibroblasts negated this response. Conclusion: The 810-nm diode laser positively affected cell proliferation and viability in all experimental groups. The statistically significant increased COL1a gene expression at 7 days after irradiation both in the irradiated HGF and co-cultures suggests that low-level laser therapy (LLLT) stimulated extracellular matrix (ECM) formation signaling in both cell types.

General genetic and acquired risk factors, and prevalence of peri-implant diseases - Consensus report of working group 1

For decades, oral implants have been used successfully for the replacement of missing teeth. Nevertheless, peri-implant diseases have become an increasingly important issue in daily practice. In this working group, the prevalence of peri-implant mucositis and peri-implantitis, as well as different general risk factors and their impact on the onset and progression of peri-implant diseases, were discussed based on reviews reflecting the current state of evidence. The influence of smoking on the peri-implant bone-healing process and its association with peri-implantitis has been explored in the current literature, demonstrating that smoking is an important risk indicator for the development of peri-implantitis and implant loss. Compared with non-smokers, smokers have a higher potential for pathological peri-implant bone loss, which is also influenced by poor oral hygiene. Despite the fact that a growing number of genetic polymorphisms have been identified and related to periodontal diseases, there are still no genetic patterns that could act as adjuncts to clinical diagnostics in order to identify patients at higher risk of peri-implant diseases. Long-term medications, such as bisphosphonate therapy (> 3 years), may have an impact on implant loss. A higher incidence of implant failure was reported in patients using selective serotonin reuptake inhibitors in anti-depression therapy. Alcoholism (defined as more than 5 units a day) has been associated with implant loss in retrospective and case-control studies, as well as in animal studies.

Spongiotic Gingival Hyperplasia Synchronously Involving Multiple Sites: Case Report and Review of the Literature

Localized juvenile spongiotic gingival hyperplasia (LJSGH) is a gingival lesion with unique clinicopathologic features that may involve synchronously multiple sites. We present a case with lesions clinically consistent with LJSGH in four jaw quadrants, confirmed by biopsy and review the English literature on multifocal LJSGH cases. A 19 year-old woman presented with circumscribed, erythematous overgrowths on the right and left maxillary and mandibular gingiva. With the provisional diagnosis of multifocal LJSGH, total excision of four maxillary lesions was performed. Clinical, microscopic and immunohistochemical examination with cytokeratin 19 confirmed the diagnosis of LJSGH in multiple sites. The excised lesions showed partial to complete recurrence after 4 months, while spontaneous regression of all but one lesion was observed after 15 months. Twenty cases with synchronous involvement of the gingiva of at least two teeth were previously reported. Their clinical features were comparable to that of solitary LJSGH. Only one case involved all four jaw quadrants. Spontaneous remission has not been documented before. The recognition of multiple lesions with clinicopathologic features diagnostic of LJSGH in the same adult patient argue against the designations "localized" and "juvenile". Recurrences are common, while remission might occur.

Xenogenic collagen matrix or autologous connective tissue graft as adjunct to coronally advanced flaps for coverage of multiple adjacent gingival recession: Randomized trial assessing non-inferiority in root coverage and superiority in oral health-related quality of life

Aim

To evaluate the non‐inferiority of the adjunct of a xenogeneic collagen matrix (CMX) or connective tissue graft (CTG) to coronally advanced flaps (CAF) for coverage of multiple adjacent recessions and compare superiority in patient‐reported outcomes (PROM).

Material and methods

One hundred and eighty‐seven subjects (92 CMX) with 485 recessions in 14 centres were randomized and followed up for 6 months. Patients filled daily diaries for 15 days to monitor patient‐reported experience. The primary outcome was changed in position of the gingival margin. Multilevel analysis used centre, subject and tooth as levels and baseline parameters as covariates.

Results

Average baseline recession was 2.5 ± 1.0 mm. The surgery was 15.7 min shorter (95%CI from 11.9 to 19.6, p < .0001) and perceived lighter (11.9 VAS units, 95%CI from 4.6 to 19.1, p = .0014) in CMX subjects. Time to recovery was 1.8 days shorter in CMX. Six‐month root coverage was 1.7 ± 1.1 mm for CMX and 2.1 ± 1.0 mm for CTG (difference of 0.44 mm, 95%CI from 0.25 to 0.63 mm). The upper limit of the confidence interval was over the non‐inferiority margin of 0.25 mm. Odds of complete root coverage were significantly higher for CTG (OR = 4.0, 95% CI 1.8–8.8).

Conclusion

Replacing CTG with CMX shortens time to recovery and decreases morbidity, but the tested generation of devices is probably inferior to autologous CTG in terms of root coverage. Significant variability in PROMs was observed among centres.

Effects of a single topical doxycycline administration adjunctive to mechanical debridement in patients with persistent/recurrent periodontitis but acceptable oral hygiene during supportive periodontal therapy

OBJECTIVES

To evaluate the efficacy of a slow release doxycycline gel (SRD) adjunctively administered to non-surgical therapy in subjects with recurrent or persistent periodontitis but acceptable oral hygiene during supportive periodontal care.

MATERIAL & METHODS

In this single blind, parallel group, multicentre study, 202 of 203 recruited periodontal maintenance subjects with recurrent or persistent periodontitis were randomly assigned to subgingival ultrasonic/sonic instrumentation (USI) with (test) or without (control) subsequent administration of SRD in all residual periodontal pockets ≥4 mm. Intergroup differences in probing depth, BOP reductions, treatment time, probing attachment levels were evaluated at 3, 6 and 12 months. The primary outcome was the inter-group difference in absolute change of probing pocket depth (PPD) 3, 6 and 12 months after intervention.

RESULTS

At baseline, the two groups were comparable. At 3 months, the test group showed a significantly higher decrease in mean probing depth than the control group at 3 months (mean difference = 0.11 mm, 95% CI 0.03-0.19 mm, p = 0.003). Administration of SRD resulted in significantly greater odds of transition of bleeding pockets ≥5 mm to a category of non bleeding sites with PPD ≤4 mm at 3 and 6 months (O.R. = 1.4, 95% CI 1.2-1.8 at 3 months). At 6 months, SRD benefit was observed only in the deeper pockets. 7.5% of subjects (no significant difference between test and control) showed disease progression (attachment loss ≥2 mm) and were exited from the study. No difference in the incidence of adverse events was observed between groups.

CONCLUSION

The trial results show that topically administered SRD may provide short-term benefit in controlling inflammation and deep pockets in treated periodontal patients participating in a secondary prevention programme and able to maintain a satisfactory level of oral hygiene.

Syndecan-1 immunohistochemical expression in gingival tissues of chronic periodontitis patients correlated with various putative factors

BACKGROUND AND OBJECTIVE

Limited information is available on the expression and distribution of syndecan-1 within human gingival tissues/cells and on putative factors that might affect its expression. Therefore, the objective of the present study was to determine immunohistochemically the expression and distribution of syndecan-1 in the gingival tissues of patients with chronic periodontitis and to examine the correlation of syndecan-1 expression with various putative factors (environmental, patient/systemic and local factors).

MATERIAL AND METHODS

Gingival specimens were surgically excised from the area of the junctional/pocket epithelium (study group 1, including 30 chronic periodontitis patients) or the gingival oral epithelium (study group 2, comprising another 30 chronic periodontitis patients), adjacent to teeth with poor prognosis. Standard two-step immunohistochemistry and semi-quantitative evaluation of immunohistochemical staining were used to determine syndecan-1 expression. Statistical analyses on the impact of various putative factors were performed.

RESULTS

In the junctional/pocket epithelium or the oral epithelium, syndecan-1 expression was weak to moderate in the suprabasal and basal epithelial cells and absent to weak in the internal basal lamina, external basal lamina and gingival connective tissue matrix. Syndecan-1 expression in the junctional/pocket epithelium was statistically significantly stronger than in the oral epithelium in inflammatory cells within the underlying gingival connective tissue (primarily plasma cells and lymphocytes) and in scattered fibroblast-like cells.

CONCLUSIONS

Syndecan-1 expression in the junctional/pocket epithelium or the oral epithelium can exhibit a significant positive correlation with the severity/degree of histologically evaluated local gingival inflammation, but in general is not significantly correlated with age, smoking, full-mouth and local clinical (probing pocket depth and clinical attachment level) and radiographical parameters (radiographical bone loss) of periodontal status.

A comprehensive and critical review of dental implant prognosis in periodontally compromised partially edentulous patients

OBJECTIVES

The outcome of implant treatment in periodontally compromised partially edentulous patients has not been completely clarified. Therefore, the aim of the present study was to perform, applying a systematic methodology, a comprehensive and critical review of the prospective studies published in English up to and including August 2006, regarding the short-term (<5 years) and long-term (>or=5 years) prognosis of osseointegrated implants placed in periodontally compromised partially edentulous patients.

MATERIAL AND METHODS

Using The National Library Of Medicine and Cochrane Oral Health Group databases, a literature search for articles published up to and including August 2006 was performed. At the first phase of selection the titles and abstracts and at the second phase full papers were screened independently and in duplicate by the three reviewers (I. K. K., S. K., I. F.).

RESULTS

The search provided 2987 potentially relevant titles and abstracts. At the first phase of evaluation, 2956 publications were rejected based on title and abstract. At the second phase, the full text of the remaining 31 publications was retrieved for more detailed evaluation. Finally, 15 prospective studies were selected, including seven short-term and eight long-term studies. Because of considerable discrepancies among these studies, meta-analysis was not performed.

CONCLUSIONS

No statistically significant differences in both short-term and long-term implant survival exist between patients with a history of chronic periodontitis and periodontally healthy individuals. Patients with a history of chronic periodontitis may exhibit significantly greater long-term probing pocket depth, peri-implant marginal bone loss and incidence of peri-implantitis compared with periodontally healthy subjects. Even though the short-term implant prognosis for patients treated for aggressive periodontitis is acceptable, on a long-term basis the matter is open to question. Alterations in clinical parameters around implants and teeth in aggressive periodontitis patients may not follow the same pattern, in contrast to what has been reported for chronic periodontitis patients. However, as only three studies comprising patients treated for aggressive periodontitis were selected, more studies, specially designed, are required to evaluate implant prognosis in this subtype of periodontitis. As the selected publications exhibited considerable discrepancies, more studies, uniformly designed, preferably longitudinal, prospective and controlled, would be important.

Immediate implant placement with transmucosal healing in areas of aesthetic priority: A multicentre randomized-controlled clinical trial I. Surgical outcomes

OBJECTIVES

To compare the clinical outcomes of standard, cylindrical, screw-shaped to novel tapered, transmucosal (Straumann Dental implants immediately placed into extraction sockets.

MATERIAL AND METHODS

In this randomized-controlled clinical trial, outcomes were evaluated over a 3-year observation period. This report deals with the need for bone augmentation, healing events, implant stability and patient-centred outcomes up to 3 months only. Nine centres contributed a total of 208 immediate implant placements. All surgical and post-surgical procedures and the evaluation parameters were discussed with representatives of all centres during a calibration meeting. Following careful luxation of the designated tooth, allocation of the devices was randomly performed by a central study registrar. The allocated SLA titanium implant was installed at the bottom or in the palatal wall of the extraction socket until primary stability was reached. If the extraction socket was >or=1 mm larger than the implant, guided bone regeneration was performed simultaneously (Bio Oss and BioGide. The flaps were then sutured. During non-submerged transmucosal healing, everything was done to prevent infection. At surgery, the need for augmentation and the degree of wound closure was verified. Implant stability was assessed clinically and by means of resonance frequency analysis (RFA) at surgery and after 3 months. Wound healing was evaluated after 1, 2, 6 and 12 weeks post-operatively.

RESULTS

The demographic data did not show any differences between the patients receiving either standard cylindrical or tapered implants. All implants yielded uneventful healing with 15% wound dehiscences after 1 week. After 2 weeks, 93%, after 6 weeks 96%, and after 12 weeks 100% of the flaps were closed. Ninety percent of both implant designs required bone augmentation. Immediately after implantation, RFA values were 55.8 and 56.7 and at 3 months 59.4 and 61.1 for cylindrical and tapered implants, respectively. Patient-centred outcomes did not differ between the two implant designs. However, a clear preference of the surgeon's perception for the appropriateness of the novel-tapered implant was evident.

CONCLUSIONS

This RCT has demonstrated that tapered or standard cylindrical implants yielded clinically equivalent short-term outcomes after immediate implant placement into the extraction socket.

A comprehensive and critical review of dental implant placement in diabetic animals and patients

OBJECTIVES

A thorough and exhaustive analysis of the available studies concerning placement of endosseous dental implants in diabetic subjects has not been previously published. The aim of the present study was to perform a comprehensive and critical review of experimental and clinical studies published in the international peer-reviewed literature in the English language regarding endosseous implant installation in diabetic subjects and to draw evidence-based conclusions on the effectiveness and predictability of dental implant therapy in diabetic patients.

MATERIAL AND METHODS

Literature search for articles published up to and including March 2005 in the English language was performed with a personal computer (PC) using The National Library Of Medicine (http://www.ncbi.nlm.nih.gov/PubMed) and Cochrane Oral Health Group databases. Search strategy included a specific series of terms and key words. The reference lists of identified publications, relevant texts and previous workshops were also scanned. Data sources also included several hand-searched journals and contact with experts, when it was considered appropriate. Search was conducted independently by the three reviewers (S. K., I. K. K., I. F.). At the first phase of selection the titles and abstracts and at the second phase full papers were screened independently by the three reviewers. Disagreement regarding inclusion of full papers was resolved by discussion among the reviewers.

RESULTS

The search provided 227 potentially relevant titles and abstracts. At the first phase of evaluation, 199 publications were rejected based on title and abstract. At the second phase, the full text of the remaining 28 publications was retrieved for more detailed evaluation. These publications included 11 experimental studies and 16 clinical studies (one clinical study corresponded to two publications). Finally, 11 experimental and eight clinical studies were accepted. Clinical studies included four prospective and four retrospective studies. Because of the limited number of available studies and their heterogeneity, focusing on a specific predefined question to be answered by a systematic review was not feasible and therefore no meta-analysis was planned.

CONCLUSION

Within the limits of the existing investigations, experimental studies seem to reveal an impaired bone healing response to implant placement in diabetic animals compared with non-diabetic controls, both quantitatively and qualitatively. The majority of clinical studies tend to indicate that diabetes is no contraindication for implant placement, on condition that it remains under metabolic control. However, definitive guidelines with objective criteria, such as type and duration of diabetes and glucosylated hemoglobin levels, need to be established in the future.

Healing, post-operative morbidity and patient perception of outcomes following regenerative therapy of deep intrabony defects

AIM

This prospective multicenter randomized controlled clinical trial was designed to compare the clinical outcomes of papilla preservation flap surgery with or without the application of enamel matrix derivatives (EMD). This article reports on early healing events, post-operative morbidity and patient perceptions of the surgical outcomes.

MATERIAL AND METHODS

One hundred and seventy-two patients with advanced chronic periodontitis and at least one intrabony defect of > or =3 mm were recruited in 12 centres in seven countries (European Research Group on Periodontology (ERGOPERIO)). Papilla preservation flaps were used to obtain access and primary closure. After debridement, and root conditioning, EMD was applied in the test subjects, and omitted in the controls. Healing was monitored 1, 2, 3, 4, 6 and 12 weeks after surgery. During the first 12 weeks of healing, supracrestal soft-tissue density was evaluated with a computer-assisted densitometric image analysis system (CADIA) using underexposed radiographs taken on a subset of 34 patients. Patient perceptions were evaluated with a questionnaire immediately after the procedure, at suture removal 1 week later and at 1 year.

RESULTS

Subjects reported little intraoperative or post-operative pain or discomfort for both test and controls. Twenty-four percent of controls and 30% of tests (p=0.64) reported a degree of interference with daily activities for an average of 3 and 3.5 days, respectively. Post-surgical edema was noted in 25% of tests and 28% of controls. Wound dehiscence in the interdental portion of the flap was uncommon (14% of tests and 12% of controls at week 1) and of limited size. Root sensitivity was the most frequent post-operative adverse event: it affected 45% of test and 35% of controls (p=0.55). Up to 6 weeks post-operatively, soft-tissue densities were significantly higher in subjects treated with EMD with respect to controls. One year after completion of the surgery, patients reported high levels of satisfaction with the outcomes. The most frequently reported benefits included the ability to preserve a tooth/dentition and to maintain/improve chewing ability. The cost and need for frequent follow-ups were cited as significant drawbacks.

CONCLUSIONS

This study portrayed the early healing events, pain, discomfort and adverse events of papilla preservation flap surgery and the 1-year patient perceptions of the benefits and disadvantages of periodontal surgery in intrabony defects. Earlier gains in soft-tissue density were observed following application of EMD. In terms of patient-centered outcomes, however, both procedures performed in a similar manner.

Clinical outcomes following treatment of human intrabony defects with GTR/bone replacement material or access flap alone. A multicenter randomized controlled clinical trial

AIM

This prospective multicenter randomized controlled clinical trial was designed to compare the clinical outcomes of papilla preservation flap surgery with or without the application of a guided tissue regeneration (GTR)/bone replacement material.

MATERIALS AND METHODS

One hundred and twenty-four patients with advanced chronic periodontitis were recruited in 10 centers in seven countries. All patients had at least one intrabony defect of > or = 3 mm. 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, the regenerative material was applied in the test subjects, and omitted in the controls. At baseline and 1 year following the interventions, clinical attachment levels (CALs), probing pocket depths (PPDs), recession, full-mouth plaque scores and full-mouth bleeding scores (FMBS) were assessed.

RESULTS

One year after treatment, the test defects gained 3.3 +/- 1.7 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 (3.7 +/- 1.8 mm) when compared with the controls (3.2 +/- 1.5 mm). A multivariate analysis indicated that the treatment, the clinical centers, baseline PPD and baseline FMBS significantly influenced CAL gains. Odds ratios (ORs) of achieving above-median CAL gains were significantly improved by the test procedure (OR = 2.6, 95% CI 1.2-5.4) and by starting with deeper PPD (OR = 1.7, 1.3-2.2) but were decreased by receiving treatment at the worst-performing clinical center (OR = 0.9, 0.76-0.99).

CONCLUSIONS

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

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.

Fractured prosthetic abutments in osseointegrated implants: a technical complication to cope with

In the present report a repair set to retrieve fractured abutments remaining in the implants of the ITI Dental Implant System is presented. In 1 case in which such fractures occurred, the repair set was successfully applied. After removal of all particles of the fractured prosthetic abutments and recutting the threads, new abutments were used, and the original suprastructure could be reinserted. The causes for such technical failures are discussed considering the relatively sparse information in the literature on that topic.

Generalizability of the added benefits of guided tissue regeneration in the treatment of deep intrabony defects. Evaluation in a multi-center randomized controlled clinical trial

BACKGROUND

Several studies have shown that GTR therapy of intrabony defects results in significantly better outcomes than access flap alone. Most of the available data, however, have been produced in highly controlled research environments by a small group of investigators. Generalizability of results to different clinicians and different subject populations has not been evaluated so far.

METHODS

This parallel group study involved 143 patients recruited in a practice-based research network of 11 offices in 7 countries. It was designed to evaluate: 1) the applicability of the documented added benefits of GTR in the treatment of intrabony defects to different populations, and 2) the generalizability of the expected results to different clinicians. GTR was compared to access flap alone. Defects, one in each patient, were accessed with a previously described papilla preservation flap in both the test and control group. In addition, GTR sites received application of a bioabsorbable poly-D,L-lactide-co-glycolide membrane. A stringent plaque control regimen was enforced in all patients during the 1-year observation period. Outcomes included gains in clinical attachment (CAL) and reductions in probing depth.

RESULTS

Observed gains in CAL were 2.18 +/- 1.46 mm for access flap and 3.04 +/- 1.64 mm for the GTR-treated group. The treatment-associated difference was statistically significant (P = 0.03) after correcting for both center effect and defect anatomy. Among the various centers, a 1.73 mm difference in CAL gain was observed. This is a clinically relevant amount, which underlines the significance of center variability in the outcome of periodontal surgical procedures. A frequency distribution analysis of the obtained CAL gains indicated that GTR treatment of deep intrabony defects decreased, with respect to the access flap control, the probability of obtaining only a modest attachment gain at 1 year. Conversely, CAL gains of 4 mm or more were observed in more than 40% of GTR-treated defects and in less than 20% of the controls (P < 0.0001).

CONCLUSIONS

These data indicate that GTR therapy of deep intrabony defects performed by different clinicians on various patient populations resulted in both greater amounts and improved predictability of CAL gains than access flap alone.

Evaluation of tetracycline fiber therapy with digital image analysis

The aims of the present study were to assess radiographically the effects of scaling/root planing combined with antibiotic therapy using tetracycline fibers (TCF): (I) on alveolar bone density and linear descriptors and (II) on supracrestal soft tissue density. 19 subjects with generalized adult periodontitis (with at least 20 teeth present, at least 4 teeth with pockets >4 mm and bleeding upon controlled force probing) and high cultural counts of Porphyromonas gingivalis were recruited from a pool of 57 patients. The full mouth treatment group (FT) consisted of 10 patients, who underwent a full mouth supra-gingival scaling and prophylaxis treatment and were instructed to rinse 2x daily with a 0.1% chlorhexidine solution. 1 week later, tetracycline-hydrochloride-containing fibers (Actisite periodontal fiber) were applied around all teeth. After 7-12 days, the fibers were removed and all teeth were scaled and root planed under local anaesthesia. The chlorhexidine rinsing continued for another 2 months. In 9 subjects (local treatment group LT), 2 teeth with periodontal lesions with pocket probing pepth (PPD) > or =5 mm were treated by placement of tetracycline fibers, which remained in place for 7 to 12 days. Upon removal of the fibers, scaling and root planing was performed on these 2 teeth, while the rest of the dentition remained untreated, and no chlorhexidine rinse was applied. 2 of the untreated teeth revealing similar periodontal lesions were chosen to represent sites affected by untreated periodontitis (NT). In this group, a limited local treatment was performed (2 teeth) with the inherent potential for recolonization from the untreated pocket sites. Standardized periapical radiographs were obtained from the 4 monitored sites within each patient at baseline (before treatment) and 2 and 6 months thereafter. One radiograph was exposed in a standard way for bone assessment. The second radiograph was underexposed, at about a 1/5 of the original exposure time to allow the evaluation of soft tissue. Mean changes in the linear parameters and changes in density (CADIA) observed at multiple sites within each patient and treatment group were used as the best estimate of treatment outcome. Over the observation period of 6 months, a significant difference in bone height changes was found between the untreated sites (median loss -0.29 mm) and the sites from full-mouth treated patients (median gain 0.24 mm, p=0.008). When comparing the baseline to the 6 months radiographs, a loss in bone density was observed for the untreated group (median=-2.13 CADIA). Both treatment groups revealed a gain in density (median=1.58 and 2.43 CADIA for the locally and the full-mouth treated groups, respectively). Differences in density were significant, both between the nontreated and locally treated sites (p=0.026) and between the nontreated sites and the sites from the full mouth treated patients (p=0.002). The analysis of the soft tissues showed a similar pattern of changes in density to those seen in the bone defect. At 2 months, there was a tendency for loss in density for the nontreated group (median=-0.17 CADIA) that continued over the 6 month period (median=-0.31 CADIA). A significant increase in density was observed for the full-mouth treated sites (median=1.57 and 0.64 CADIA for the 2 and 6 months radiographs, respectively). A significant increase was also observed for the locally treated group when compared to the untreated sites (median=0.13 and 0.10 CADIA for the 2 and 6 months radiographs, respectively). Comparing untreated sites with full-mouth treated sites, a significant difference was observed for CADIA measurements (p<0.001). No significant difference was observed comparing locally treated and untreated sites (p=0.24). It was concluded that scaling and root planing combined with TCF therapy can result in increased bone density and alveolar bone height. Full-mouth treatment seemed to result in more pronounced gains compared to local tre

Computer-assisted densitometric image analysis of digital subtraction images: in vivo error of the method and effect of thresholding

The aim of the present study was to assess the in vivo error of the method as well as the effect of thresholding when obtaining and evaluating standardized periapical radiographs for computer-assisted densitometric image analysis (CADIA). Twenty healthy volunteers participated in an experimental gingivitis study in which neither mechanical nor chemical plaque control was performed for 21 days. Two pairs of standardized periapical radiographs were taken at days 0 (baseline) and 21 (follow-up), one from a maxillary area (15 volunteers) and one from a mandibular molar/premolar area (17 volunteers). Each baseline radiograph was digitized and its image displayed on a monitor. The follow-up radiograph was then superimposed and digitized as well. After gray level correction, subtraction radiographic images were produced. The difference in gray level between the baseline and the follow-up image was calculated within each region of interest (ROI) at each picture point (pixel). In bone ROI, changes in density reflected the amount of change due to methodological errors plus the basic bone remodeling over 3 weeks. For gingival ROI, changes in density reflected the methodological error plus a possible change in soft tissue density during the experimental gingivitis. Within all of the ROI, some pixels indicated a change in gray level. A change in gray level was then thresholded; i.e., only changes >5 and then >10 gray levels were registered and used for calculation of the CADIA values. With a threshold of 5, 44/45 maxillary bone ROI and 60/66 mandibular bone ROI showed a change in density, while 41/45 maxillary gingiva ROI and 26/66 mandibular gingiva ROI indicated a change in density. With a threshold of 10, 16/45 maxillary bone ROI and 12/66 mandibular bone ROI indicated a change in density, while 13/45 maxillary gingiva ROI and 1/66 mandibular gingiva ROI indicated a change. The amounts of changes in density calculated in the various ROI were low even when applying no threshold, ranging from -0.279 to 0.621. Applying a threshold of 5, the CADIA values ranged from -0.234 to 0.727. With a threshold of 10, the changes in density ranged from -0.318 to 0.133. In vivo, CADIA of standardized radiographs indicated change in density due to methodological errors. Application of thresholds may avoid false-positive diagnoses. When applying CADIA in clinical research, the range of change to be expected due to methodological limitations as well as the threshold for true change should be evaluated. These thresholds may differ in various areas of the mouth, i.e., bone or gingival, maxillary/mandibular, anterior/posterior ROI.

Effect of the NSAID flurbiprofen on remodelling after periodontal surgery

The aim of the present experiment was to assess the effect of the administration of the NSAID flurbiprofen (Froben) on tissue healing after periodontal surgery. Sites from patients with the same treatment modality (modified Widman flap) but receiving a placebo drug and sites within each patient not exposed to surgery served as controls. Nineteen patients suffering from moderate to severe periodontal disease were recruited and they signed informed consent forms. These patients required periodontal surgery as assessed at the periodontal re-evaluation. The sites chosen for the study were all diagnosed with PPD > or = 5 mm and were bleeding on probing. During the healing phase 10 patients received 50 mg Froben 3 times per day for 30 d whereas 9 patients received a placebo drug. Two sites with PPD > or = 5 mm after initial therapy and bleeding on probing served as surgical sites, whereas 2 similar sites were not exposed to surgery. The study design was set up double-blind. The radiographic examination consisted of 2-4 standardized vertical bitewings obtained at the periodontal re-evaluation (BL) at 1, 3 and 6 months post-surgically for digital subtraction and computer assisted densitometric image analysis (CADIA). The regions of interest analysed were mesial or distal crestal sites. Minimal remodelling activity was observed radiographically after periodontal surgery in both patient groups. There were no statistically significant differences between the four groups of sites regarding the mean changes in density when analysing the pairs of radiographs 0-1, 0-3, 0-6 months. A frequency analysis was performed to list the number of sites with different ranges of density change. No differences in the distributions of the numbers of sites were observed when comparing the 4 site groups (Kolmogorov-Smirnov, p > 0.05). A significant reduction of the probing pocket depth and a significant amount of clinical attachment gain was noted at the surgically treated sites irrespective of whether the patients had used flurbiprofen or placebo. Whereas the pathways leading to bone resorption in periodontally diseased sites have been shown, in other studies, to be influenced by NSAID, the results of the present study could not justify general administration of Froben for the purpose of reduction of bone resorption after periodontal surgical procedures in patients with adult periodontitis.

Use of an internal standard in subtraction radiography to assess initial periodontal bone changes

OBJECTIVE

To assess the use of an internal reference when performing histogram analyses in digital subtraction images and to determine the ability of the method to detect initial bone lesions.

METHODS

Fifty-one Royal Air Force recruits had standardized vertical bitewing radiographs and clinical assessment of attachment level recorded annually over three years. Subtraction analyses of crestal bone changes at the mesial surface of the upper right first molar were compared with changes at the mesial surface of the same tooth. Changes over the periods from age 17 to 18 years and age 18 to 20 years were monitored using two subtraction procedures.

RESULTS

Reproducibility studies revealed that Pearson correlations between duplicate measurements of the test site alone (16 crest; r = 0.74) were lower than those between duplicate measurements of changes where misalignment was controlled for, either as a difference (16 crest-16 tooth; r = 0.93) or ratio (16 crest/16 tooth; r = 0.93). We used the differences between the mean subtraction density for 16 crest and 16 tooth as our measure of change in bone density. For the duplicate measurements, the standard deviation of these differences was 3.9: a difference of +/- 7.8 was therefore taken as a threshold value for evidence of real change. Bone gain was noted between the ages of 17 and 18 years (16/21 subjects), but some early bone loss was seen between 18 and 20 years (12/21 subjects), with four subjects showing changes significantly greater than the method error. There were no associations between the clinical and radiographic observations.

CONCLUSION

Use of a control site in subtraction radiography improves the reproducibility; such systems can detect small changes in alveolar bone which may assist in early diagnosis of the initial periodontal lesion which may precede observable clinical changes.

Successful bone fill in late peri-implant defects using guided tissue regeneration. A short communication

Severe loss of peri-implant supporting bone traditionally leads to the removal of the affected implant, but this may not be necessary in all cases. This paper presents a novel treatment approach aimed at the successful regeneration of bone lost to peri-implantitis using guided tissue regeneration (GTR). Four years after implant placement two patients presented with severe peri-implant tissue breakdown. Clinical signs of disease included bleeding on probing, suppuration, increased probeable pocket depth (4 to 9 mm) and a decreased level of clinical attachment (2 to 10 mm). Radiographic analysis revealed 2.6 to 7.1 mm loss of supporting bone. Treatment of these lesions included raising flaps, wound debridement, and rinsing with sterile saline and 0.2% chlorhexidine digluconate. Subsequently, ePTFE membranes were adapted around the necks of the implants and the flaps sutured around the necks of the implants, allowing for transmucosal healing. Both patients were placed on a 10-day antibiotic regimen and instructed to rinse twice daily with a 0.12% chlorhexidine solution. They were reevaluated every 3 weeks at which time professional plaque control was performed. After 4 1/2 and 6 1/2 months, respectively, the membranes required removal due to infection. The radiographic analysis 1 year after membrane removal revealed 1.5 to 3.6 mm of bone gain. As a result of regenerative therapy the implants in both these patients were successfully maintained. It can be concluded that implants with severe loss of bone resulting from peri-implantitis need not always be extracted. A potential approach for the treatment of peri-implant bone destruction is GTR therapy using strict attention to good antimicrobial therapy.

Guided bone regeneration around an immediate transmucosal implant for single tooth replacement: a case report

This case report describes the procedure of guided bone regeneration around an endosseous dental implant, placed into an extraction alveolus in the absence of total soft tissue coverage, ie, in a transmucosal condition. The technique presented permits an immediate placement of the implant after the extraction of the maxillary right lateral incisor. A nonresorbable barrier membrane was used, and strict chemical plaque control was maintained during osseointegration. After an uneventful healing period of 6 months, the membrane was removed in a second-stage surgery. Two months later, the fixed single tooth prosthesis was placed. The learning objective of this article is to explain the immediate transmucosal implant surgery technique, using a case report to illustrate the procedure.

Digital image processing. II. In vitro quantitative evaluation of soft and hard peri-implant tissue changes

The aim of this study was to evaluate the ability of computer-assisted densitometric image analysis (CADIA) to detect small changes in mineralized and nonmineralized tissues adjacent to dental implants and to correlate these changes with CADIA values. A section of a pig mandible including all soft tissues and in which a hollow cylinder ITI Bonefit implant with an artificial mesial and a buccal infrabony defect was placed was used to obtain pairs of standardized radiographs. Series of radiographs were obtained with exposure times of 0.13, 0.20, 0.44, and 0.53 s. Specimens of mineralized or nonmineralized tissues were placed arbitrarily in the defects before each radiographic exposure. The radiographs were captured through a video camera, digitized and stored in a personal computer. Every radiographic image was then subtracted from a baseline one without any change. The result of the subtraction was evaluated with CADIA. A linear correlation (r2 = 0.99) was found between the bone chips (1-5 mg of dry weight) placed in the mesial defect and the CADIA values. Bone chips in the buccal defect (behind the implant), however, were not detected unless their weight reached 14 mg or more. For conventionally exposed radiographs, it was not possible to recognize soft tissue specimens (1-6 mg), either in the buccal or the mesial defect. However, when "underexposed" radiographs (exposure time: 0.13 s) were obtained, a linear correlation (r2 = 0.80) was calculated for soft tissue specimens in the mesial defect and CADIA values. In normally exposed radiographs, the CADIA system could detect even the smallest change in bone density (bone chip of 1 mg of dry bone weight) and correlated almost linearly with these changes. Provided that the radiographic images are obtained with standardized geometry and normal exposure time, the tissue density changes detected by this system within bone defects represent only mineralized tissue changes. By underexposing radiographs, CADIA may even reveal soft tissue changes around dental implants.

Digital image processing. I. Evaluation of gray level correction methods in vitro

The aims of this study were a) to assess in an in vitro model the amount of density changes measured in digitally subtracted images due to electronic noise and image alignment error, and b) to test the accuracy of different gray level correction procedures in the reduction of densitometric image mismatches. A section of a pig mandible in which a hollow cylinder ITI Bonefit implant had been placed was used to obtain pairs of standardized radiographs. Series of radiographs were obtained with different exposure times (0.34, 0.39, 0.44, 0.51, 0.58 s). The radiographs were captured through a video camera, digitized and stored in a personal computer. The same radiographic image was recorded and subtracted from itself 10 times to study the error of the method due to electronic transformations of the images and image alignment. The noise due to the analog-to-digital transformation of the radiographic images was calculated to be +/- 2 gray levels i.e., 2% of the scale of gray levels. This kind of error was reduced up to 40% by capturing the images more than once and averaging the values per pixel. The manual superimposition of the images to be subtracted caused an increase of the error to +/- 3 gray levels (2.7%). Seven methods of gray level correction based either on a linear least squares approximation or on the cumulative density function (CDF) were tested. The group based on the CDF algorithm gave significantly better results than any other method. Pixels yielding differences smaller or equal to +/- 7 gray levels (5.5% of the scale of gray levels) should be excluded from further calculations in order to eliminate (false-positive) errors due to the normalizing algorithms. Furthermore, the CDF method on an arbitrarily chosen area of the image or on the wedge seems to give to subtraction images the ability of revealing real subtle changes in tissue density (fewer false-negative errors). The use of reference structures did not futher improve the ability of the normalization methods to correct gray level mismatches between radiographic pairs.

Treatment of an early implant failure according to the principles of guided tissue regeneration (GTR)

The present case report demonstrates the application of guided tissue regeneration (GTR) in combination with antimicrobial therapy for the treatment of an early implant failure. This treatment approach both prevented further loss of bone as well as led to the regeneration of lost bone. By means of color-converted digital subtraction images, remodelling of the tissues adjacent to the defect was documented as early as one month postsurgically. The images demonstrated "bone-fill" in the apical portion of the defect and resorptive changes at the bone crest. This case report demonstrates that combined regenerative and antimicrobial therapy may be a successful treatment approach restoring osseointegration of dental implants following loss of bone due to infection. Continuously increasing bone-fill inside the defect was documented when comparing the radiograph obtained immediately before the GTR procedure and at months 1, 2, 4, 5 and 6 of the healing period, respectively. Clinical measurement obtained at the time of the surgery and at the time of the membrane removal confirmed the radiographic evidence of bone-fill by demonstrating new tissue resistant to probing in close contact to the implant surface at the site of the previous defect. Antimicrobial therapy included an antibiotic regimen during the 1st month of healing as well as topical rinses with an antiseptic (chlorhexidine) over the entire healing period of 6 months. As a result of this treatment approach, the implant was saved and could be used as an abutment for a bridge reconstruction.