A bivariate multi-level model, which avoids mathematical coupling in the study of change and initial periodontal attachment level after therapy

When relating the change of periodontal attachment level to its baseline value, mathematical coupling has to be taken into account. Oldham's strategy of testing the differences in variances of two repeated measurements was recently advocated as a possible solution. Here, a simple bivariate three-level (site and subject with a lowest level specifying the multivariate structure) model is introduced where gingival units (sites) were nested in subjects. It allows the easy interpretation of the variance-covariance structure and fixed model estimates, and provides an unbiased estimate of the correlation between the mean and change of periodontal measurements. The properties of this model are exemplified using data of a study on the clinical effects of non-surgical periodontal therapy in adults. Based on the covariance terms, correlation between the change in clinical attachment after therapy and the mean of the pre-operative and post-operative attachment level was very low (about -0.11, p < 0.001) at the site level, and not significant at the subject level. Regarding the attachment level, differential treatment effects may be neglected. With regard to periodontal probing depth, however, patients with larger extent and severity would benefit more from treatment. The present communication provides an easy strategy for the avoidance of mathematical coupling in the study between change and initial value by employing a bivariate multi-level model.

Disease recurrence following reconstructive procedures: a 6- to 8-year follow-up observational study

PURPOSE

The aims of the present study were to determine (i) the long-term disease recurrence in intraosseous defects that had undergone an open flap debridement (OFD) procedure with or without enamel matrix derivative (EMD); and (ii) whether and to what extent clinical changes recorded on teeth treated with surgery were similar at sites involved or adjacent to the intraosseous defect.

MATERIALS AND METHODS

Eleven patients contributing twelve reconstructed intraosseous defects were retrospectively recruited and included for analysis. Immediately before surgery, at 12 months post-surgery and at long-term examination (6-8 years post-surgery), probing pocket depth (PPD) and clinical attachment level (CAL) were recorded at the test site (representative of the reconstructed intraosseous defect) and the control site (representative of an adjacent non-reconstructed site) of each tooth treated with surgery.

RESULTS

All patients received monthly professional maintenance up to 12 months after surgery, and every 6 months or less frequently thereafter. In test sites, CAL varied from 5.4 +/- 0.8 mm at 12 months to 6.5 +/- 1.0 mm at the long-term examination. PPD increased from 3.7 +/- 0.4 mm at 12 months to 4.3 +/- 0.6 mm at the long-term examination, the changes being not statistically significant. When PPD and CAL changes from 12 months to the long-term examination were compared between test and control sites, no significant differences were found.

CONCLUSIONS

Within its limitations and considering the limited sample size, the present study indicates that (i) the attachment gain that has been achieved by means of a surgical reconstructive procedure (based on OFD with/without EMD) may be mostly maintained over a 6-8 year follow-up period; and (ii) the extent of disease recurrence, as assessed by attachment loss and pocket deepening, was similar at sites involved or adjacent to the intraosseous defect.

Histologic and clinical evaluation of an allogeneic bone matrix for the treatment of periodontal osseous defects

The objective of this study was to evaluate the potential of an allogeneic bone matrix (Grafton, Osteotech) to regenerate new bone, new cementum, and a new periodontal ligament around teeth previously contaminated by bacterial plaque. Four patients with chronic advanced periodontitis and who were scheduled for full-mouth extraction were enrolled in the study. One patient dropped out from the study before any therapy began. One tooth with an intraosseous defect in each patient was selected for treatment. Measurements of probing depth, gingival recession, and clinical attachment level were made. After flap reflection, a root notch was placed at the apical level of calculus, the root was debrided, and allogenic bone matrix was inserted into the defect. After 6 months of healing, the teeth were removed en bloc and evaluated histologically for a new attachment apparatus. Two of the three teeth demonstrated regeneration of new bone, cementum, and periodontal ligament.

A two-year prospective study of coronally positioned flap with or without acellular dermal matrix graft

AIM

Evaluation of the treatment of gingival recessions with coronally positioned flap with or without acellular dermal matrix allograft (ADM) after a period of 24 months.

METHODS

Thirteen patients with bilateral gingival recessions were included. The defects were randomly assigned to one of the treatments: coronally positioned flap plus ADM or coronally positioned flap alone. The clinical measurements were taken before the surgeries and after 6, 12 and 24 months.

RESULTS

At baseline, the mean values for recession height were 3.46 and 3.58 mm for the defects treated with and without the graft, respectively (p>0.05). No significant differences between the groups were observed after 6 and 12 months in this parameter. However, after 24 months, the group treated with coronally positioned flap alone showed a greater recession height when compared with the group treated with ADM (1.62 and 1.15 mm, respectively--p<0.05). A significant increase in the thickness of keratinized tissue was observed in the group treated with ADM as compared with coronally positioned flap alone (p<0.05).

CONCLUSIONS

ADM may reduce the residual gingival recession observed after 24 months in defects treated with coronally positioned flap. In addition, a greater gingival thickness may be achieved when the graft is used.

Diabetes enhances periodontal bone loss through enhanced resorption and diminished bone formation

Using a ligature-induced model in type-2 Zucker diabetic fatty (ZDF) rat and normoglycemic littermates, we investigated whether diabetes primarily affects periodontitis by enhancing bone loss or by limiting osseous repair. Diabetes increased the intensity and duration of the inflammatory infiltrate (P < 0.05). The formation of osteoclasts and percent eroded bone after 7 days of ligature placement was similar, while four days after removal of ligatures, the type 2 diabetic group had significantly higher osteoclast numbers and activity (P < 0.05). The amount of new bone formation following resorption was 2.4- to 2.9-fold higher in normoglycemic vs. diabetic rats (P < 0.05). Diabetes also increased apoptosis and decreased the number of bone-lining cells, osteoblasts, and periodontal ligament fibroblasts (P < 0.05). Thus, diabetes caused a more persistent inflammatory response, greater loss of attachment and more alveolar bone resorption, and impaired new bone formation. The latter may be affected by increased apoptosis of bone-lining and PDL cells.

Effect of mechanical and antiseptic therapy on peri-implant mucositis: an experimental study in monkeys

OBJECTIVES

This experiment was performed to evaluate clinically and histologically the effect of mechanical therapy with or without antiseptic therapy on peri-implant mucositis lesions in nine cynomolgus monkeys.

MATERIAL AND METHODS

Two ITI titanium implants were inserted into each side of the mandibles. After 90 days of plaque control and soft tissue healing, a baseline clinical examination was completed. Peri-implant lesions were induced by placing silk ligatures and allowing plaque to accumulate for 6 weeks. The clinical examination was then repeated, and the monkeys were randomly assigned to three treatment groups: group A, mechanical cleansing only; group B, mechanical cleansing and local irrigation with 0.12% chlorhexidine (CHX) and application of 0.2% CHX gel; and group C, control, no treatment. The implants in treatment groups A and B were treated and maintained according to the assigned treatment for two additional months. At the end of the maintenance period, a final clinical examination was performed and the animals were sacrificed for biopsies.

RESULTS

The mean probing depths (PD) values at mucositis were: 3.5, 3.7, and 3.4 mm, and clinical attachment level (CAL) = 3.8, 4.1, and 3.9 mm for treatment groups A, B and C, respectively. The corresponding values after treatment were: PD = 1.7, 2.1, and 2.5 mm, and CAL=2.6, 2.6, and 3.1 mm. ANOVA of mean changes (Delta) in PD and CAL after treatment showed no statistical difference between the treatment groups. Comparison of the mean changes in PD and CAL after treatment yielded statistical differences between the control and treatment groups P < 0.01. According to the t-test, no statistical difference was found between treatment groups A and B for the PD reduction but there was a significant difference for the CAL change, P < 0.03. Group A had significantly more recession and less CAL gain than group B. Non-parametric tests yielded no significant differences in modified plaque index (mPlI) and gingival index (GI) after treatment between both treatment groups. Frequencies and percent distributions of the mPlI and GI scores changed considerably for both treatment groups when compared with the changes in the control group after treatment. With regard to the histological evaluation, no statistical differences existed between the treatments for any linear measurement. The proportion of inflammation found in the mucosal tissues of the control implants was greater than the one found for both treatment groups, P < 0.01. More importantly, both treatment groups showed a similar low proportion of inflammation after 2 months of treatment.

CONCLUSIONS

Within the limitations of this experiment, and considering the supportive plaque control rendered, it can be concluded that for pockets of 3-4 mm: (1) mechanical therapy alone or combined with CHX results in the clinical resolution of peri-implant mucositis lesions, (2) histologically, both treatments result in minimal inflammation compatible with health, and (3) the mechanical effect alone is sufficient to achieve clinical and histologic resolution of mucositis lesions.

Short-term clinical and microbiologic effects of pocket debridement with an Er:YAG laser during periodontal maintenance

BACKGROUND

The erbium-doped:yttrium, aluminum, and garnet (Er:YAG) laser is considered a useful tool for subgingival debridement because the laser treatment creates minimal damage to the root surface and has potential antimicrobial effects. The aim of this randomized controlled clinical trial was to evaluate clinical and microbiologic effects of pocket debridement using an Er:YAG laser in patients during periodontal maintenance.

METHODS

Twenty patients at a recall visit for maintenance were consecutively recruited if presenting at least four teeth with residual probing depth (PD) > or = 5 mm. Two pockets in each of two jaw quadrants were randomly assigned to subgingival debridement using 1) an Er:YAG laser (test) or 2) an ultrasonic scaler (control). The laser beam was set at 160 mJ with a pulse frequency of 10 Hz. Clinical variables were recorded at baseline, 1 month, and 4 months after treatment. Primary clinical outcome variables were changes in PD and clinical attachment level (CAL). Microbiologic analysis of subgingival samples was performed at baseline, 2 days, and 30 days after treatment using a checkerboard DNA-DNA hybridization technique against 12 periodontal disease-associated species.

RESULTS

The mean initial PD was 6.0 mm (SD: 1.2) in the test group and 5.8 mm (SD: 0.9) in the control group. At 1 month post-treatment, the PD reduction was significantly greater for test than control sites (0.9 versus 0.5 mm; P <0.05). The CAL gain also was significantly greater (0.5 versus 0.06 mm; P <0.01). At the 4-month examination, no significant differences were detected in PD reduction (1.1 versus 1.0 mm) or CAL gain (0.6 versus 0.4 mm). Both treatments resulted in reduction of the subgingival microflora. No significant differences in microbiologic composition were identified between the treatment groups at various time intervals. Degree of treatment discomfort scored significantly lower for the test than the control treatment modality.

CONCLUSION

The results of the trial failed to demonstrate any apparent advantage of using an Er:YAG laser for subgingival debridement, except less treatment discomfort perceived by the patients.

Factors Influencing Treatment Outcomes in Mandibular Class II Furcation Defects

BACKGROUND

Factors influencing treatment outcomes in furcation defects remain to be studied. Therefore, the aim of the study was to evaluate the association between factors and clinical parameters that may influence treatment outcomes in mandibular Class II furcation defects.

METHODS

Twenty-seven systemically healthy subjects with a Class II buccal or lingual furcation defect in lower molars were treated. Clinical measurements (probing depth [PD], clinical attachment level [CAL], recession, mobility, plaque index [PI], and bleeding on probing [BOP]) and defect (vertical and horizontal defect depths) were obtained at initial and 6-month reentry surgeries. Treatment modalities (e.g., nine each in the following three groups: open flap debridement [OFD] alone, bone graft [BG], and bone graft plus a bioabsorbable collagen membrane [BG + C]), anatomic factors (presence of cervical enamel projection, presence of cervical restorations/fixed prosthesis, and location of furcations [buccal or lingual sides; first or second molars]), clinical parameters (initial mobility, initial PD at furcation, initial CAL at furcation, mean initial PD of the tooth, mean initial CAL of the tooth, initial horizontal PD at furcation, initial horizontal/vertical defect depth, PI, and BOP), and background factors (endodontic status, smoking status, and surgeon's experience) were analyzed for associations with probability of clinical improvement.

RESULTS

The anatomic factors, clinical parameters, and background information were found to have no effect in influencing treatment outcome with the exception of initial vertical defect depth. An initial vertical defect depth >or=4 mm had a borderline significance (P = 0.06) of achieving a high probability of having a 1-mm vertical bone fill. In addition, treatment modality was found to be a major influence factor. Sites treated with BG were 16x more likely to have >50% vertical bone fill than open flap surgery. Furthermore, sites treated with BG were 64x more likely to have a 1-mm vertical defect fill compared to sites treated with OFD and 16x more likely to have a 2-mm vertical defect fill compared to sites treated with OFD or BG + C. However, the additional membrane does not enhance the regenerative outcomes achieved by BG alone.

CONCLUSIONS

Initial vertical defect depth (>or=4 mm) and treatment modality (e.g., BG) were found to be the clinical parameter and factor that were associated with high probability of clinical improvement. Sites treated with BG, such as mineralized human cancellous allograft, were more likely to have greater vertical furcation defect fill than the conventional OFD surgery. Additional membrane placement does not enhance the treatment outcome achieved by BG alone.

Estimation of the remaining periodontal ligament from attachment-level measurements

AIM

Accurate assessment of the remaining area of periodontal attachment assists in determining the prognosis of a tooth. The aim of this study was to determine formulae to estimate the remaining area of periodontal attachment from attachment-level measures.

MATERIALS AND METHODS

Roots of 30 extracted teeth of each tooth type were coated with vinyl acetate solution and alpha-cyanoacrylate monomer to produce a membrane. The membrane was removed after guidelines were drawn to simulate various attachment levels. The root surface area on the apical side of each simulated attachment level was measured using image analysis software. The net or percent root surface area and corresponding attachment level data were fitted to a linear, quadratic, cubic, and exponential functions and a growth curve.

RESULTS

The linear function provided the most appropriate fit for the data. For net root surface area, a steeper slope was evident for tooth types with a larger mean total root surface area. For percent root surface area, a steeper slope was evident for tooth types with a shorter root length.

CONCLUSIONS

A linear function provides the most appropriate formula for estimation of the remaining area of periodontal attachment based on the attachment-level measurement.

The expression profile of lipopolysaccharide-binding protein, membrane-bound CD14, and toll-like receptors 2 and 4 in chronic periodontitis

BACKGROUND

This study aimed to investigate the interrelationship of in vivo expression of lipopolysaccharide-binding protein (LBP) and membrane-bound CD14 (mCD14) in human gingival tissues as well as the coexpression of Toll-like receptors (TLR) 2 and 4 in association with periodontal conditions.

METHODS

Gingival biopsies were collected from 43 subjects with chronic periodontitis, including periodontal pocket tissues (PoTs) and clinically healthy gingival tissues (HT-Ps), and from 15 periodontally healthy subjects as controls (HT-Cs). The expression of LBP, CD14, TLR 2, and TLR 4 was detected by immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

LBP and mCD14 peptides were simultaneously detected in 91% of PoTs, 85% of HT-Ps, and 100% of HT-Cs. LBP and mCD14 mRNAs were simultaneously detected in 55% of PoTs, 55% of HT-Ps, and 75% of HT-Cs. The expression of LBP was confined to the gingival epithelium, whereas mCD14 was observed around the epithelium-connective tissue interface. A positive correlation existed between LBP and mCD14 peptides in both detection expression (r(s) = 0.608; P <0.001) and expression levels (r = 0.304; P <0.05) of these two molecules. In PoTs, TLR 2 was detected in both pocket epithelia and macrophage-like cells in connective tissues, whereas TLR 4 was predominantly detected in connective tissues. In HT-Ps and HT-Cs, a weak expression of TLR 2 was found in gingival epithelia, and no TLR 4 expression was detected. In PoTs, mCD14 was codetected on CD68-labeled macrophages in the underlying connective tissues of pocket epithelium as well as on CD1a-labeled dendritic cells in the pocket epithelium and connective tissues interface. No similar expression profile was detected in HT-Ps and HT-Cs.

CONCLUSIONS

This study suggests that the in vivo expression of LBP and mCD14 may be interrelated. Altered cellular expression profiles of mCD14 and TLR 2 and 4 in periodontal pocket tissues imply that these pattern recognition receptors may play a role in periodontal pathogenesis.

Coronally Positioned Flap for Root Coverage: Poorer Outcomes in Smokers

BACKGROUND

Gingival recession is significantly more common among smokers, while the relative outcome of various root coverage procedures in smokers, compared to non-smokers, is debatable. The objective of this study was to evaluate the influence of cigarette smoking on the outcome of coronally positioned flap (CPF) in the treatment of Miller Class I gingival recession defects.

METHODS

Ten current smokers (> or = 10 cigarettes daily for at least 5 years) and 10 non-smokers (never smokers), each with one 2- to 3-mm Miller Class I recession defect in an upper canine or bicuspid, were treated with CPF. At baseline and 6 months, clinical parameters, probing depth (PD), clinical attachment level (CAL), recession depth (RD), and apico-coronal width of keratinized tissue (KT) were determined.

RESULTS

Intragroup analysis showed that CPF was able to reduce RD and improve CAL in both groups (P <0.05). Intergroup analysis demonstrated that smokers presented greater residual RD at 6 months and lower percentage of root coverage (69.3% versus 91.3%; P <0.05). No smokers obtained complete root coverage compared to 50% of non-smokers (P <0.05).

CONCLUSIONS

Within the limits of the present study, it can be concluded that CPF provides benefits for both smokers and non-smokers in terms of root coverage of shallow Miller Class I recession defects. However, cigarette smoking negatively impacts the clinical outcomes, specifically residual recession, percent root coverage, and frequency of complete root coverage.

Clinical and histological healing pattern of peri-implantitis lesions following non-surgical treatment with an Er:YAG laser

BACKGROUND AND OBJECTIVES

The aim of the present study was to assess clinical and histo-pathological healing pattern of peri-implantitis lesions following non-surgical treatment with an Er:YAG laser (ERL).

STUDY DESIGN/MATERIALS AND METHODS

Twelve patients suffering from peri-implantitis (n = 12 implants) received a single episode of non-surgical instrumentation using ERL (12.7 J/cm2). Assessment of clinical parameters (plaque index (PI), bleeding on probing (BOP), probing pocket depth, gingival recession (GR), and clinical attachment level (CAL)), surgical defect examination, and histo-pathological examination of peri-implant tissue biopsies was performed after 1, 3, 6, 9, 12, and 24 months.

RESULTS

All patients exhibited improvements of all clinical parameters investigated. However, histo-pathological examination of tissue biopsies revealed a mixed chronic inflammatory cell infiltrate (macrophages, lymphocytes, and plasma cells) which seemed to be encapsulated by deposition of irregular bundles of fibrous connective tissue showing increased proliferation of vascular structures.

CONCLUSION

It was concluded that a single course of non-surgical treatment of peri-implantitis using ERL may not be sufficient for the maintenance of failing implants.

Enamel Matrix Derivative and Coronal Flaps to Cover Marginal Tissue Recessions

BACKGROUND

Correcting recession defects is one of the goals of periodontal therapy, and the efficacy and predictability of the various techniques are important considerations for both patients and clinicians. Several reports have examined the outcome of gingival recession treatment by means of coronally positioned flaps (CPF) and enamel matrix derivative (EMD). The purpose of this study was to clinically evaluate the use of EMD in association with CPF to cover localized gingival recessions compared to CPF alone.

METHODS

Twenty-two patients with Miller Class I or II gingival recessions >2 mm were included. One recession from each patient was treated in the study. Two treatments were randomly assigned: coronally positioned flap with EMD (test) and coronally positioned flap alone (control). Clinical parameters measured at baseline and 1, 6, and 12 months included gingival index, plaque index, probing depth, clinical attachment level, vertical and horizontal recession, and width of keratinized gingiva.

RESULTS

At 12 months, both treatment modalities showed significant root coverage, gain in clinical attachment, and gain in width of keratinized gingiva (P <0.05). Vertical recessions were reduced from 2.68 +/- 1.63 mm to 0.36 +/- 0.60 mm in the test group and from 2.31 +/- 1.52 mm to 0.90 +/- 0.95 mm in the control group. Horizontal recessions decreased from 4.27 +/- 2.06 mm to 0.77 +/- 0.87 mm in the test group and from 3.68 +/- 1.91 mm to 1.72 +/- 1.31 mm in the control group. Changes in keratinized gingiva went from 3.81 +/- 1.95 mm to 4.63 +/- 2.15 mm in the test group and from 3.31 +/- 1.81 mm to 3.27 +/- 1.80 mm in the control group. When both treatments were compared at 12 months, there was a significant difference in vertical tooth coverage and gain in keratinized gingiva in favor of the experimental group (P <0.05). The average percentage of root coverage for test and control groups was 88.6% and 62.2%, respectively.

CONCLUSIONS

The coronally positioned flap alone or with EMD is an effective procedure to cover localized gingival recessions. The addition of EMD significantly improves the amount of root coverage.

Smoking affects the self-healing capacity of periodontal tissues. A histological study in the rat

This study aimed to evaluate in rats the impact of cigarette smoke inhalation (CSI) and nicotine administration (NA) on a periodontal healing model in the absence of a plaque biofilm. Wistar rats (n = 42) were assigned to three groups: Group 1, control (n = 14); Group 2, NA (3 mg kg(-1)) (n = 14); and Group 3, CSI (n = 14). Thirty days after CSI and NA exposure, fenestration defects were created buccally to the distal root of the first mandibular molar. The animals were killed 21 d later and their mandibles were processed for histological examination. The percentage of bone fill and the density of newly formed bone were assessed histometrically. Intergroup analysis demonstrated that compared to the control and NA groups, CSI was associated with a reduced rate of bone repair. No new cementum had been formed along the root surface in any of the three groups. It is concluded that cigarette smoke reduces the self-healing capacity of periodontal tissues.

Coverage of Miller Class I and II Recession Defects Using Enamel Matrix Proteins Versus Coronally Advanced Flap Technique: A 2-Year Report

BACKGROUND

The aim of this study was to evaluate a comparison of the coronally advanced flap procedure with or without the use of enamel matrix proteins in the treatment of recession defects.

METHODS

This 2-year study was conducted as a blinded, split-mouth, placebo-controlled, and randomized design. Thirty patients from two dental schools with two paired buccal recession defects were chosen. Surgical recession coverage was performed as the coronally advanced flap technique. One site was additionally treated with derivative (EMD) and the other site with a placebo (propylene glycol alginate [PGA]). A blinded examiner assessed pre- and post-surgical measurements. Measurements comprised the height and width of the gingival recession, height of keratinized tissue, probing attachment level, probing depth, and alveolar bone level.

RESULTS

Twenty-four months after therapy, both treatment modalities showed significant root coverage and probing attachment gain. The mean gingival recession decreased from 3.6 to 0.8 mm for the EMD-treated sites and from 3.8 to 1.4 mm for the control sites. However, this difference was not statistically significant (P = 0.122). Similarly, all other clinical parameters did not differ significantly in the between-group comparison except for the recession width (P = 0.027) and probing depth (P = 0.046) exhibiting higher reductions in the EMD group. Complete root coverage could be maintained over 2 years in 53% of the EMD versus merely 23% in the control group. A total of 47% of the treated recessions in the control group deteriorated again in the second year after therapy compared to 22% in the EMD group.

CONCLUSION

Enamel matrix derivative seems to provide better long-term results.

Clinical attachment level change as an outcome measure for therapies that slow the progression of periodontal disease

Attachment levels are excellent indicators of past destruction of the periodontal attachment apparatus and can be used to monitor the progression of periodontitis. They have been used in clinical trials to monitor the efficacy of a variety of therapeutic modalities that may either slow the progression of periodontal disease or allow for regeneration of lost attachment and supporting structures. Inherent difficulties in accurately assessing attachment levels include inflammation, which causes coronal displacement of the gingival margin without a concomitant migration of the dentogingival epithelium to a level apical to the cementoenamel junction, and recessions, in which an obvious loss of attachment has occurred, but there is no increase in probing depth. Attachment level measurements are more frequently used as clinical end-points in clinical trials than by private practitioners to determine the periodontal status of patients and to monitor patient responses to periodontal therapy. Clinical attachment level measurements have been used in clinical trials to evaluate a systemic host modulatory agent, demonstrating their utility as surrogate markers of efficacy.

The effect of cigarette smoking on the severity of periodontal disease among older Thai adults

BACKGROUND

The aim of this study is to determine the effect of cigarette smoking on the severity of periodontitis in a cross-sectional study of older Thai adults.

METHODS

The study population consisted of 1,960 subjects (age 50 to 73 years old). All subjects received both medical and dental examinations. Periodontal examinations, including plaque score, probing depth, and clinical attachment level, were done on all teeth present in two diagonal quadrants. Sociodemographic characteristics and smoking status were obtained by questionnaires. Multinomial logistic regression was used to address the association between cigarette consumption and mean clinical attachment level.

RESULTS

In this study population, 48.7% were non-smokers, 14.4% were current smokers, and 36.9% were former smokers. Current smokers had higher percentage of sites with plaque, deeper mean probing depth, and greater mean clinical attachment level than former smokers and non-smokers. The odds of having moderate and severe periodontitis for current smokers were 1.7 and 4.8 times greater than non-smokers, respectively. Former smokers were 1.8 times more likely than non-smokers to have severe periodontitis. Quitting smoking reduced the odds of having periodontitis. For light smokers (<15 packyear), the odds for severe periodontitis reverted to the level of non-smokers when they had quit smoking for > or =10 years. For moderate and heavy smokers (> or =15 packyear), the odds of having severe periodontitis did not differ from those of non-smokers when they had quit smoking for > or =20 years.

CONCLUSIONS

There was a strong association between cigarette smoking and the risk of periodontitis among older Thai adults. Quitting smoking appears to be beneficial to periodontal health.

Quantitative Measures of Aggressive Periodontitis Show Substantial Heritability and Consistency With Traditional Diagnoses

BACKGROUND

Aggressive periodontitis (AgP) research nearly always classifies subjects into traditional discrete categories of localized or generalized, based upon degree of attachment loss (AL) and types of affected teeth. Since AL is continuous and quantitative, however, useful information is lost. We developed quantitative measures of AgP, compared these to traditional methods, and estimated heritabilities in families.

METHODS

We examined 237 healthy, 169 localized AgP, and 204 generalized AgP subjects. We used the site of maximum AL of each tooth to calculate means for each subject for different groups of teeth. We also applied principal components analysis (PCA) to condense variation among 28 teeth into three orthogonal (uncorrelated) variables. We used discriminant function analysis (DFA) to evaluate how well the quantitative measures match with traditional classifications. Quantitative trait heritabilities were estimated by variance components.

RESULTS

PCA clustered first molars, incisors, and the other teeth into three groups. DFA showed that quantitative measures classified subjects consistent with traditional methods (87% to 94% agreement). Heritabilities ranged from 13.7% (P = 0.10) to 30.0% (P = 0.008) for quantitative measures, with highest values obtained for first molars. A combination of the principal component variables most heavily weighted on first molars and incisors gave the best model of disease susceptibility, with good separation of healthy versus diseased subjects, independent of disease extent or severity.

CONCLUSIONS

Quantitative measures may provide improved precision and power for many kinds of periodontal research. Our finding of significant heritability supports their use in gene mapping studies of AgP susceptibility.

Prevalence of horizontal attachment loss in extracted teeth

OBJECTIVE

Probing attachment level provides useful information on patterns of destruction of the periodontium. It is difficult to detect complex attachment loss in clinics. The purpose of this study was to estimate prevalence of vertical and horizontal attachment loss in extracted teeth.

MATERIAL AND METHODS

We collected 10,212 extracted teeth from 130 dentists in Japan. After staining of periodontal membrane with erythrosine, linear loss of vertical and horizontal attachment was measured using a digital caliper.

RESULTS

Mean vertical attachment loss varied from 5.3 to 8.6 mm. Incisors had severe attachment loss at mesial sites. Specific local attachment loss at palatal sites was observed in maxillary premolars and molars as well as in mandibular canines and premolars. Horizontal attachment loss was observed in 23% of the teeth. Frequency of horizontal attachment loss of > or = 2.1 mm was 6.4%.

CONCLUSION

Severe attachment loss was observed on the palatal side of maxillary premolars. More than 1/3 of the maxillary first molars showed horizontal attachment loss. It may be impossible to debride 6.4% of teeth in cases of severe periodontitis because horizontal attachment loss may be deeper than the curette blade length.

A short-term and long-term comparison of root coverage with an acellular dermal matrix and a subepithelial graft

BACKGROUND

Obtaining predictable and esthetic root coverage has become important. Unfortunately, there is only a limited amount of information available on the long-term results of root coverage procedures. The goal of this study was to evaluate the short-term and long-term root coverage results obtained with an acellular dermal matrix and a subepithelial graft.

METHODS

An a priori power analysis was done to determine that 25 was an adequate sample size for each group in this study. Twenty-five patients treated with either an acellular dermal matrix or a subepithelial graft for root coverage were included in this study. The short-term (mean 12.3 to 13.2 weeks) and long-term (mean 48.1 to 49.2 months) results were compared. Additionally, various factors were evaluated to determine whether they could affect the results. This study was a retrospective study of patients in a fee-for-service private periodontal practice. The patients were not randomly assigned to treatment groups.

RESULTS

The mean root coverages for the short-term acellular dermal matrix (93.4%), short-term subepithelial graft (96.6%), and long-term subepithelial graft (97.0%) were statistically similar. All three were statistically greater than the long-term acellular dermal matrix mean root coverage (65.8%). Similar results were noted in the change in recession. There were smaller probing reductions and less of an increase in keratinized tissue with the acellular dermal matrix than the subepithelial graft. None of the factors evaluated resulted in the acellular dermal graft having a statistically significant better result than the subepithelial graft. However, in long-term cases where multiple defects were treated with an acellular dermal matrix, the mean root coverage (70.8%) was greater than the mean root coverage in long-term cases where a single defect was treated with an acellular dermal matrix (50.0%).

CONCLUSIONS

The mean results with the subepithelial graft held up with time better than the mean results with an acellular dermal matrix. However, the results were not universal. In 32.0% of the cases treated with an acellular dermal matrix, the results improved or remained stable with time.

Healing of periodontal defects treated with enamel matrix proteins and root surface conditioning—an experimental study in dogs

Application of enamel matrix proteins has been introduced as an alternative method for periodontal regenerative therapy. It is claimed that this approach provides periodontal regeneration by a biological approach, i.e. creating a matrix on the root surfaces that promotes cementum, periodontal ligament (PDL) and alveolar bone regeneration, thus mimicking the events occurring during tooth development. Although there have been numerous in vitro and in vivo studies demonstrating periodontal regeneration, acellular cementum formation and clinical outcomes via enamel matrix proteins usage, their effects on the healing pattern of soft and hard periodontal tissues are not well-established and compared with root conditioning alone. In the present study, the effects of Emdogain (Biora, Malmö, Sweden), an enamel matrix derivative mainly composed of enamel matrix proteins (test), on periodontal wound healing were evaluated and compared with root surface conditioning (performed with 36% orthophosphoric acid) alone (control) histopathologically and histomorphometrically by means of the soft and hard tissue profile of periodontium. An experimental periodontitis model performed at premolar teeth of four dogs were used in the study and the healing pattern of periodontal tissues was evaluated at days 7, 14, 21, 28 (one dog at each day), respectively. At day 7, soft tissue attachment evaluated by means of connective tissue and/or epithelial attachment to the root surfaces revealed higher connective tissue attachment rate in the test group and the amount of new connective tissue proliferation in the test group was significantly greater than the control group (p<0.01). New bone formation by osteoconduction initiated at day 14 in the test and control group. At day 21, the orientation of supra-alveolar and PDL fibers established, and new cementum formation observed in both groups. At day 28, although regenerated cementum was cellular in all of the roots in the control samples, an acellular type of cementum (1.32+/-0.83 mm in length and 3.16+/-0.23 microm in width) was also noted in six roots of test samples with an inconsistent distribution on the root surfaces. The amount of new cementum was significantly higher in the test group than the control group samples (p<0.01). The width of the cellular cementum in the control group was more than the cellular cementum in the test group, but the difference was not statistically significant (p>0.05). A firm attachment of acellular cementum to the root dentin with functional organization of its collagen fibers was noted, and, the accumulation and organization of cellular cementum in the control group was more irregular than the cellular cementum formed in the test group. The amount of new bone was 2.41+/-0.75 mm in the test and 1.09+/-0.46 mm in the control group at day 28. The rate of bone maturation (the number of osteons) was found higher in the test group (10.75+/-0.85) than the control group (5.50+/-0.86). Under the limitations of the study, our results reveal that when compared with root surface conditioning, enamel matrix proteins have more capacity for stimulating periodontal regeneration via their positive effects on root surfaces, i.e. inhibition of gingival epithelium down growth and stimulation of connective tissue proliferation and attachment to the root surfaces during wound healing. An acellular type of cementum regeneration and new alveolar bone formation by an accelerated osteoconductive mechanism are also achieved with application of enamel matrix proteins.

Susceptibility of GTR-regenerated periodontal attachment to ligature-induced periodontitis. An experiment in the monkey

AIM

This study aimed to compare the susceptibility of guided tissue regeneration (GTR)-regenerated periodontal attachment to ligature-induced periodontitis with that of the pristine periodontium.

METHODS

Periodontal breakdown was produced in four monkeys by the placement of orthodontic elastics around experimental teeth (test teeth). During a flap operation, the root surfaces were scaled and planed, and a notch indicating the apical termination of scaling and root planing was made in the root surface. Following resection of the crowns and endodontic treatment, an e-PTFE membrane was adapted over the roots. Subsequently, the flaps were sutured to complete closure of the wound (submerged). At membrane removal after 5 weeks, the crowns of the contralateral teeth serving as controls were resected, and the roots treated endodontically during a flap operation. Artificial composite crowns were then placed on both test and control roots. After 3 months of tooth cleaning, cotton floss ligatures were placed passively around both test and control teeth for a period of 6 months. Two weeks later the animals were sacrificed.

RESULTS

Histological analysis demonstrated that the instrumented root surfaces of the test teeth were covered by newly formed cementum of the reparative, cellular, extrinsic and intrinsic fiber type, while the cementum on the controls was mainly acellular extrinsic fiber cementum. Histometric assessments demonstrated that similar attachment loss had occurred on test (1.0+/-0.5 mm) and control roots (1.0+/-0.4 mm) during the 6 months of ligature-induced plaque accumulation.

CONCLUSION

The results indicate that teeth with a periodontal attachment apparatus formed by GTR is not more susceptible to periodontitis than those with a pristine periodontium.

Comparative value of attachment measurements in implant dentistry

PURPOSE

In implant dentistry, the level of bone attachment is normally assessed by clinical and radiologic parameters. In the literature, however, the accuracy of these measurements has been a source of controversy. The purpose of this study was to assess the reliability of attachment measurements in the beagle dog model.

MATERIALS AND METHODS

In 6 beagle dogs, a total of 60 implants were placed. Bony defects resulting from plaque accumulation were treated surgically. All defects were evaluated at the time of surgery (T3) and 4 months later (T4). Evaluation included standardized measurements on radiographs, pressure-forced implant probing, and histometry. Furthermore, both conventional and digital radiographic techniques were used.

RESULTS

Both radiographic techniques showed very similar results at T3 and T4. At time T4, pressure-forced probing revealed statistically significantly different values than those obtained with radiography and histometry. When radiographic and histometric measurements were compared, no significant differences were found at either time T3 or time T4.

DISCUSSION

In this study, histometry showed better accordance with radiography than with pressure-forced probing. These results support the hypothesis that peri-implant attachment should be evaluated with a combination of both clinical and radiologic parameters.

CONCLUSION

The exclusive use of radiography cannot be recommended for the measurement of peri-implant attachment.

Matrix metalloproteinases and their inhibitors in gingival mast cells in persons with and without human immunodeficiency virus infection

BACKGROUND

Mast cells are a prominent cell type in the gingival infiltrate in periodontitis. In this study we examined the expression by gingival mast cells of matrix metalloproteinases, MMP-1, MMP-2, MMP-8 and the tissue inhibitors of metalloproteinases, TIMP-1 and TIMP-2.

METHODS

Gingival specimens from 12 human immunodeficiency virus-negative (HIV-) and 15 HIV-positive (HIV+) patients with chronic marginal periodontitis (CMP), and from 10 HIV- and four HIV+ controls with clinically healthy gingiva (HG) were examined after double immunofluorescence staining for mast cell tryptase, combined with antibodies for MMP-1, MMP-2, MMP-8 or their inhibitors TIMP-1 and TIMP-2.

RESULTS

In the HIV+CMP, HIV+HG and HIV-CMP groups, all mast cells expressed MMP-1 and MMP-8, whereas a smaller proportion (40-60%) in the HIV-HG controls displayed such staining. The former groups also displayed a significantly higher proportion (39-64%) of mast cells expressing MMP-2 as compared with the HIV-HG group (21-31%). All groups displayed similar proportions of TIMP-1 expressing mast cells (86-100%), whereas significantly increased proportions of TIMP-2+ mast cells were seen in the HIV+CMP, HIV+HG and HIV-CMP groups (18-25%) as compared with the HIV-HG group (8-13%). Mast cells were the cell type that most prominently expressed MMP-1 and MMP-8. MMP-2 expression was also strong in mast cells, but was also similarly expressed in other cell types.

CONCLUSION

The chronically inflamed periodontal lesions in the present study appeared with little evidence of mast cell degranulation. The results show, however, that mast cells in inflamed gingiva have the potential to degrade extracellular matrix if appropriately triggered.