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The anti-plaque. anti-gingivitis and anti-microbial efficacies of a phenolic compound (Listcrine®) and 2 different amine/stannous fluoride mouthwashes (Meridol® I, II) were compared when these solutions were used in addition to usual toothcleaning. A placebo preparation was utilized as a negative control and a chlorhexidine solution as a positive control in this double-blind study. After professional toothcleanling, 49 volunteers continued their habitual, self- performed and non-supervised oral hygiene for a period of 2 weeks, in order to have a more standard baseline. At day 0. they began to rinse twice daily with 1 of the 5 mouthwashes. After 3 weeks of rinsing, plaque indices remained the lowest in the chlorhexidine and the Meridol® I groups, while subjects using Listerine® or Meridol® II demonstrated similar indices significantly lower than that of individuals rinsing with the placebo solution. Through this period, the gingival index scores were similar in the Meridol® Listerine® and chlorhexidine groups. At day 21, the mean GI scores in the chlorhexidine group were significantly lower than the scores in the placebo group. The plaque vitality scores showed a bacterial effect in vivo of chlorhexidine and, to a lesser extent, of the Meridol® solutions. No substantial evidence of an antibacterial effect in vivo was found for Listerine®. This study has demonstrated that when mouthrinses are used to supplement habitual mechanical oral hygiene, chlorhexidine remains the most powerful solution. Furthermore, it was also shown that a combination of habitual self-performed and non-supervised oral hygiene with Meridol® or Listerine® is more beneficial for plaque control than the use of mechanical oral hygiene alone. [ABSTRACT FROM AUTHOR]

The aim of the present study was to compare stereologically the histopathologic variations following 3 weeks of chemical (chlorhexidine) or mechanical plaque control. 18 students and dental hygienists volunteered for this investigation. After prophylaxis, they performed optimal oral hygiene to reach mean plaque and gingival indices approaching 0. Six of them then performed mechanical plaque control of 3 weeks (control), while the other 12 rinsed 3 times daily with a 0.12% chloridixidine solution (test). At days 0 and 21, the plaque index (PlI), the gingival index (Gl) and the gingival exudate flow rate (GEFR) were assessed and biopsies were obtained from buccal sites. Point-counting procedures were performed at 2 different levels of magnification on light microscopic sections to estimate the volume fractions of epithelium, infiltrated and non-infiltrated connective tissue, and collagen. The relative numbers of fibroblasts, polymorphonuclear neutrophils, lymphocytes, plasma cells, macrophages and mast cells were estimated by counting the number of nuclear profiles of these cells in a specific connective tissue area adjacent to the apical termination of the junctional epithelium. After 21 days, the PlIs of the test subjects were significantly higher than the PlIs of the controls, but their Gl were similar. At the end of the experimental period, the various volume fractions and %s of cell profiles remained stable with the exception of an increase in the %s of lymphocytes in the test group. This study has shown that, clinically as well as histologically, the daily use of chlorhexidine for a 3-week period is equally effecient as optimal mechanical tooth cleaning in maintaining a healthy gingiva in the buccal sites investigated. [ABSTRACT FROM AUTHOR]

The aim of the present study was to investigate stereologically the histologic alterations occurring during gingival healing after experimental gingivitis and to compare clinical parameters with histological findings. 8 dental students volunteered for the investigation. After a prophylaxis, they performed optimal oral hygiene to reach mean plaque and gingival indices approaching zero. They then abolished all oral hygiene procedures for a period of 21 days. After this experimental gingivitis phase, they again performed optimal oral hygiene for 8 days to restore gingival health. At days 0, 1, 2, 4 and 8 after experimental gingivitis, the plaque index (PlI), the gingival index (GI) and the gingival exudate flow rate (GEFR) were assessed and their buccal gingiva was biopsied. Point counting procedures were performed at 2 different levels of magnification on light microscopic sections to estimate the volume fractions of epithelium, infiltrated and non-infiltrated connective tissue, and collagen. The relative numbers of fibroblasts, polymorphonuclear neutrophils, lymphocytes, plasma cells and macrophages were estimated by counting the number of profiles of these cells in a specific connective tissue area adjacent to the apical end of the junctional epithelium. A rapid drop in the PlI was noted with increasing time after oral hygiene, followed by a slower decrease in the GI and GEFR scores. The histological picture during the entire experiment was that of an initial gingival lesion. At day 0, no chronic inflammation of the gingiva characterized by a predominance of plasma cells was observed. After resumption of oral hygiene when the relative cell numbers at day 0 and day 8 were compared, only an increase in the PMN population was observed. As GI and GEFR scores decreased no significant changes were noted in the relative numbers of the various cell types. These observations suggest that the "physiogenesis during experimental health" appears first clinically and then histologically, and hence, it may take more than 8 days to observe significant variations in cell populations. [ABSTRACT FROM AUTHOR]

The polymorphonuclear neturophil (PMN) appears to be an important cell in the protection of the host form pathogenic periodontal micro-organisms. The purpose of the present histological studies was to observe the emigration of the PMN from the gingival vessels to the periodontal pocket during gingivitis and ligature-induced periodontitis in the cynomolgus monkey. 2 adult female monkeys were treated by application of a silk ligature around selected posterior teeth. After 9 weeks, the monkeys were perfused and block sections of both ligated (early periodontitis) and non-ligated (gingivitis) sites were obtained, cut into smaller blocks containing a single interdental area (N = 15 for periodontitis, N = 5 for gingivitis) and processed for light and electron microscopic observations. Morphologically, no differences in PMNs between gingivitis and periodontitis were observed and therefore the following description applies to both disease states. In the vessels, the endothelial cells appeared to be actively involved in PMB emigration, maintaining long processes which surrounded the PMNs. Within the connective tissue, the PMNs maintained their typical morphology which included polylobated nuclei and numerous lysosomal granules. Many intact PMNs were observed intercellulary within the connective tissue and the epithelium. Within the periodontal pocket, a multiplayer of PMNs surrounded the plaque mass. Cells with numerous bacteria-containing phagolysosomes were observed with increasing frequency as they approached the plaque. Deeper within the bacterial deposit, PMNs were seen in varying stages of degeneration. These histologic studies, when interpreted in the light of reports of severe, rapidly-progressive periodontitis in patients with PMN disorders, suggest that the interaction of PMNs with bacterial plaque may serve to maintain a defensive boundary which protects the host tissues form irreversible destruction. [ABSTRACT FROM AUTHOR]

AbstractBackground: Enamel matrix proteins (EMD) have recently been introduced in regenerative periodontal treatment. However, no histological data are yet available concerning the effect of treating intrabony periodontal defects with EMD, and no histological comparisons have been made comparing the result of treatment of intrabony defects with EMD with that of the treatment with guided tissue regeneration (GTR). Aim: Therefore, the aim of the present study was to evaluate histologically in monkeys the effect of treating intrabony defects with EMD, GTR or combined EMD and GTR. Method: Intrabony periodontal defects were produced surgically at the distal aspect of teeth 14, 11, 21, 24, 34, 31, 41 and 44 in 3 monkeys (Macaca fascicularis). In order to prevent spontaneous healing and to enhance plaque accumulation metal strips were placed into the defects. After 6 weeks the defects were exposed using a full-thickness flap procedure. The granulation tissue was removed and the root surfaces were debrided by means of hand instruments. Subsequently, the defects were treated using one of the following therapies: (i) GTR, (ii) EMD, or (iii) combination of EMD and GTR. The control defects were treated with coronally repositioned flaps. After 5 months, the animals were sacrificed and perfused with 10% buffered formalin for fixation. Specimens containing the defects and surrounding tissues were dissected free, decalcified in EDTA and embedded in paraffin. 8 μm thick histological sections were cut and stained and subsequently examined under the light microscope. Results: In the control specimens, the healing was characterized by a long junctional epithelium and limited periodontal regeneration (i.e., new periodontal ligament, new cementum with inserting connective tissue fibers and new bone) in the bottom of the defect. The GTR-treated defects consistently presented periodontal regeneration when the membranes were not exposed whereas the sites treated only with EMD presented regeneration to a varying extent. The combined therapy did not seem to improve the results. Conclusion: It can be concluded that all 3 treatment modalities favor periodontal regeneration. [ABSTRACT FROM AUTHOR]

The purpose of the present study was to determine by means of a fluorescence test the ratio between vital and dead bacteria in dental plaque before and after 0.1% chlorhexidine rinses. Plaque was stained by fluoresceindiacetate (FDA), which gave a green color to the living micro-organisms, and by ethidium-bromide (EB), which introduced a red color into the nucleic acids of the dead bacteria. 1-, 2- and 3-day-old undisturbed plaque harbored 80 to 85% living micro-organism. 1 h after chlorhexidine use, this % was reduced to a plateau of 19 to 34% of vital bacteria present in the sampled plaque. Between 6 and 8h later, this % rose towards its original value. This study has shown that FDA/EB staining provides a method for direct measurement of bacteria vitality in dental plaque and, as such, can be of great value for testing the efficacy of various antiplaque agents. [ABSTRACT FROM AUTHOR]

Objectives: This pilot study aimed to assess dimensional changes following two different alveolar socket sealing techniques. Material and methods: Twenty-one patients requiring tooth extraction and implant placement were randomly allocated to two different alveolar ridge preservation techniques. In the control group, demineralized bovine bone mineral (DBBM) and a gingival soft tissue punch were used to fill and seal the socket, whereas in the test group, the extraction socket was filled with DBBM and sealed with a hemostatic gelatin sponge. Digitalized impressions were taken before and 6 months after tooth extraction. The comparison was made on horizontal and vertical dimensional changes. Results: The mean vertical loss was 0.8 ± 0.6 mm for the control group and 0.7 ± 0.5 mm for the test one. No statistical difference was found between groups for the vertical shrinkage. The horizontal dimensional narrowing of the alveolar socket was respectively 7.1/4.0/2.5 mm at levels 1, 3, and 5 mm from a coronal reference level for the control group. The test group showed dimensional changes of 4.8/2.3/1.3 mm at the three different levels, respectively. A significant difference was found at levels 3 and 5 mm. Referring to a visual analog pain scale, patients reported more severe pain in the control group (5.7/10) when compared with the test group (2.8/10). The difference was statistically highly significant (P ≤ 0.001). Conclusions: A significant difference was found between control and test groups regarding the horizontal dimensional changes and the post-operative pain. Clinical relevance: Regarding this primary result, the socket sealing technique with a hemostatic sponge provides an effective and inexpensive protocol with less post-operative pain. [ABSTRACT FROM AUTHOR]

The purpose of this 4-day plaque regrowth study was to assess the effect of N-chlorotaurine (NCT) mouth rinses on plaque inhibition and plaque vitality. Eighty volunteers participated in this investigator-blind, randomized, clinical controlled study in parallel groups. No oral hygiene was permitted except rinsing with a 2% or 3% NCT mouth rinse, a positive or a negative control. Primary parameters were the plaque index (Silness and Löe, Acta Odontol Scand, 22:121–135, ) and plaque vitality (Netuschil et al., J Clin Periodontol, 16:484–488, ) after the final rinse. In addition, another plaque index (Turesky et al., J Periodontol, 41:41–43, ), plaque area, and bleeding on probing were recorded. All parameters were taken at baseline and day 5. U test was applied on a 5% error level. No differences in plaque inhibition were found between the two NCT formulations and the negative control. However, a statistically significant reduction of plaque vitality compared to the negative and positive control was observed. Discoloration of the tongue and unpleasant taste were recorded in participants in the NCT groups. NCT mouth rinses did not inhibit plaque regrowth, but they did reduce the vitality of plaque bacteria. Methods of prolonging the substantivity of the NCT mouth rinses should be investigated to enhance the antibacterial properties of these formulations. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this experimental gingivitis study was to assess the efficacy and safety of two new chlorhexidine (CHX) mouthrinses. Materials and Methods: Ninety volunteers participated in this investigator-blind, randomized, clinical-controlled trial in parallel groups. During the treatment period, no oral hygiene measures except rinsing with non-alcoholic 0.2% CHX or 0.2% CHX/0.055% sodium fluoride mouthrinses, a positive control, or a negative control were permitted. The primary parameter was the gingival index; the secondary parameters were plaque index, discolouration index, and bleeding on probing. Clinical examinations were conducted 14 days before the start of the study, at baseline, and after 7, 14, and 21 days. The two sample t-test,anova, andancova were used for the statistical analysis. Results: No difference in efficacy was found between the two new CHX formulations and the positive control. On day 21, statistically significantly less gingival inflammation and plaque accumulation compared with placebo were observed. Besides discolouration and taste irritations, no adverse events were recorded. Conclusion: The two new CHX mouthrinses were able to inhibit plaque re-growth and gingivitis. Neither the omission of alcohol nor the supplementation with sodium fluoride had weakened the clinical efficacy of CHX with respect to the analysed clinical parameters. [ABSTRACT FROM AUTHOR]

AIM: The purpose of the present study was to compare clinically the treatment of deep intra-bony defects with a combination of a composite bovine-derived xenograft (BDX Coll) and a bioresorbable collagen membrane [guided tissue regeneration (GTR)] to access flap surgery only. METHODS: Thirty-two patients, each of whom displayed one intra-bony defect, were treated either with BDX Coll+GTR (test) or with access flap surgery (control). The results were evaluated at 1 year following therapy. RESULTS: No differences in any of the investigated parameters were observed at baseline between the two groups. Healing was uneventful in all patients. At 1 year after therapy, the test group showed a reduction in the mean probing depth (PD) from 8.3+/-1.5 to 2.9+/-1.3 mm (p<0.001) and a change in the mean clinical attachment level (CAL) from 9.4+/-1.3 to 5.3+/-1.5 mm (p<0.0001). In the control group, the mean PD was reduced from 8.0+/-1.2 to 4.4+/-1.7 mm (p<0.001) and the mean CAL changed from 9.6+/-1.3 to 7.9+/-1.6 mm (p<0.01). The test treatment resulted in statistically higher PD reductions (p< or =0.05) and CAL gains (p<0.001) than the control one. In the test group, all sites (100%) gained at least 3 mm of CAL. In this group, a CAL gain of 3 or 4 mm was measured at 10 sites (62%), whereas at six sites (38%), the CAL gain was 5 or 6 mm. In the control group, no CAL gain occurred at three sites (19%), whereas at 10 sites (62%), the CAL gain was only 1 or 2 mm. A CAL gain of 3 mm was measured in three defects (19%). CONCLUSIONS: Within the limits of the present study, it can be concluded that the combination of BDX Coll+GTR resulted in significantly higher CAL gains than treatment with access flap surgery alone, and thus appears to be a suitable alternative for treating intra-bony periodontal defects. [ABSTRACT FROM AUTHOR]

The aim of the present study was to compare newly formed cementum following different types of regenerative therapy in humans. Eighteen patients, each displaying one advanced intrabony defect around teeth scheduled for extraction, were included in this study. The defects were treated with either guided tissue regeneration (GTR), enamel matrix protein derivative (EMD), EMD plus bioactive glass, bovine-derived xenograft (BDX), BDX plus GTR, or BDX plus EMD. After healing, the teeth were removed together with their surrounding soft and hard tissues. Cellular content, presence of artifactual splits between the new cementum and the old one or the dentin surface, and thickness of the new cementum were evaluated. Irrespective of treatment, the new cementum was of a reparative, cellular, extrinsic and intrinsic fiber type. There were no differences in cementum thickness among treatments. These findings indicate that in humans, (a) the new cementum formed after different types of regenerative therapy was, irrespective of the treatment, of a reparative, cellular, extrinsic and intrinsic fiber type, and (b) the regenerative modality does not seem to influence the type of newly formed cementum. [ABSTRACT FROM AUTHOR]

BACKGROUND: Treatment with enamel matrix proteins (EMD) or guided tissue regeneration (GTR) has been shown to enhance periodontal regeneration. However, until now there are limited data on the long-term results following these treatment modalities. Aim: The aim of the present clinical study was to present the 5-year results following treatment of intrabony defects with EMD, GTR, combination of EMD and GTR, and open flap debridement (OFD). MATERIAL AND METHODS: Forty-two patients, each of whom displayed one intrabony defect of a probing depth of at least 6 mm, were randomly treated with one of the four treatment modalities. The following parameters were evaluated prior to surgery, at 1 year and at 5 years after: plaque index, gingival index, bleeding on probing, probing pocket depth (PPD), gingival recession, and clinical attachment level (CAL). No statistically significant differences in any of the parameters were observed at baseline between the four groups. RESULTS: The sites treated with EMD demonstrated a mean CAL gain of 3.4+/-1.1 mm (p<0.001) and of 2.9+/-1.6 mm (p<0.001) at 1 and 5 years, respectively. The sites treated with GTR showed a mean CAL gain of 3.2+/-0.8 (p<0.001) at 1 year and of 2.7+/-0.9 mm (p<0.001) at 5 years. The mean CAL gain at sites treated with EMD+GTR was 3.0+/-1.0 mm (p<0.001) and 2.6+/-0.7 mm (p<0.001) at 1 and 5 years, respectively. The sites treated with OFD demonstrated a mean CAL gain of 1.6+/-1.0 mm (p<0.001) at 1 year and 1.3+/-1.2 mm (p<0.001) at 5 years. At 1 year, the only statistically significant difference between the four different treatments was found in terms of PPD reduction and CAL gain between EMD and OFD (p<0.05). However, at 5 years there were no statistically significant differences in any of the investigated parameters between the four different treatments. CONCLUSION: Within the limits of the present study, it may be concluded that the short-term clinical results following treatment with EMD, GTR, EMD+GTR, and OFD can be maintained over a period of 5 years. [ABSTRACT FROM AUTHOR]

OBJECTIVES: The aim of this prospective, randomized, controlled clinical study was to compare the effectiveness of a newly developed ultrasonic device to that of scaling and root planing for non-surgical periodontal treatment. MATERIAL AND METHODS: Thirty-eight patients with moderate to advanced chronic periodontal disease were treated according to an 'one-stage procedure' with either a newly developed ultrasonic device (VUS) (Vector-ultrasonic system) or scaling and root planing (SRP) using hand instruments. Clinical assessments by plaque index (PlI), gingival index (GI), bleeding on probing (BOP), probing depth (PD), gingival recession (GR), and clinical attachment level (CAL) were made prior to and at 6 months after treatment. Differences in clinical parameters were analyzed using the Wilcoxon signed ranks test and Mann and Whitney U-test. RESULTS: No differences in any of the investigated parameters were observed at baseline between the two groups. The mean value of BOP decreased in the VUS group from 32% at baseline to 20% after 6 months (p<0.001) and in the SRP group from 30% at baseline to 18% after 6 months (p<0.001).The results have shown that at moderately deep sites (initial PD 4-5 mm) mean CAL changed in the test group from 4.6+/-1.2 to 4.2+/-1.6 mm (p< 0.001) and in the control group from 4.8+/-1.3 to 4.4+/-1.5 mm (p<0.001). At deep sites (initial PD>6 mm) mean CAL changed in the test group from 8.5+/-1.9 to 7.9+/-2.4 mm (p<0.001) and in the control group from 7.9+/-1.6 to 7.2+/-2.2 mm (p<0.001). No statistically significant differences in any of the investigated parameters were found between the two groups. CONCLUSION: Non-surgical periodontal therapy with the tested ultrasonic device may lead to clinical improvements comparable to those obtained with conventional hand instruments. [ABSTRACT FROM AUTHOR]

Application of enamel matrix protein derivative (EMD) onto a debrided and conditioned root surface has been shown to promote periodontal regeneration in animals and humans. However, until now there is virtually no information from humans describing the expression of different matrix molecules in the newly formed periodontal tissues following treatment with EMD. This study investigated immunohistochemically in humans the expression of matrix molecules associated with periodontal tissues reformed after treatment with EMD. Eight patients with intrabony defects were treated with EMD. Six months after surgery teeth together with some of their surrounding soft and hard tissues were removed, fixed in buffered formalin, decalcified in EDTA, and embedded in paraffin. Serial sections of 6 µm were cut in mesiodistal direction. Sections were evaluated immunohistochemically by means of polyclonal antibodies against osteopontin, collagen I and collagen III. The original (non-treated) parts of the periodontium served as controls. In all specimens the healing resulted to a varying extent in formation of cementum, periodontal ligament and alveolar bone. In all specimens the expression of the investigated matrix molecules was stronger at the reformed than at the original sites. Osteopontin expression was most intense at the border near the newly formed cementum and bone. In the regenerated periodontal ligament, collagen I and III were localized throughout the entire periodontal ligament connective tissue. Within the newly formed PDL connective tissue the immunohistochemical staining appeared stronger for collagen III than for collagen I. The present findings suggest that (a) treatment of human intrabony defects with EMD creates an environment favourable for periodontal regeneration and, (b) in humans the healing and/or remodelling process of the reformed tissues may be followed immunohistochemically for a period of 6 months. [ABSTRACT FROM AUTHOR]

The effect of chlorhexidine (CHX) on the viability of Streptococcus sanguinis was investigated in a preclinical biofilm model separately on cells in the planktonic or attached life form. Saliva-coated human enamel and glass slides were exposed to the streptococci suspended in sterile saliva for 30 min and 60 min in the flow chamber system. The CHX exposition was performed in two parts: pretreatment of the planktonic bacteria before their attachment to enamel or glass, and treatment of bacteria already attached to enamel. The susceptibility measured by vitality percentages was determined by fluorescence microscopy using vital/dead cells. After CHX pretreatment of planktonic cells, the mean values of the vitality percentages after adhesion were 14–18% (enamel) and 24–25% (glass). In contrast, the mean vitality percentages of untreated attached streptococci reached 70–75% (enamel) and 68% (glass). The vitality percentages of CHX-exposed bacteria dropped markedly to 2–5%, whereas those of untreated attached cells remained at 65–66%. The exposure of initially attached streptococci to CHX resulted in greater reduction of bacterial viability than with the planktonic counterparts. This preclinical biofilm model allows the investigation of various bacterial life forms and can furthermore be used to select efficient antiplaque therapeutics which might be beneficial for clinical plaque control. [ABSTRACT FROM AUTHOR]

The expression of vimentin is well documented in the intact animal and human periodontal ligament (PDL), but there is limited information on the pattern of vimentin expression in the regenerated PDL.The aim of the present study was to investigate the pattern of vimentin expression in the regenerated and intact monkey and human PDL.A total of 12 chronic recession-type defects were created in three monkeys (Macaca fascicularis) and treated either with guided tissue regeneration (GTR), or with an enamel matrix protein derivative (EMD). After 5 months, the animals were sacrificed and specimens containing the defects and surrounding tissues were dissected free, decalcified in EDTA and embedded in paraffin. Sections were labelled immunohistochemically by using monoclonal antibody against vimentin (VIM 3B4).Twelve patients, each of whom displayed one deep intrabony defect scheduled for extraction were treated with GTR, EMD or combination of EMD+natural bone mineral (NBM). Following a healing period of 6 months, the teeth were extracted “en block” and immunohistochemically analysed according to the same protocol as described in monkeys.The results revealed that in both monkeys and humans the newly formed PDL was labelled similarly for vimentin to the intact (non-treated) PDL. In all specimens, the newly formed PDL was in continuation with the intact parts of PDL, thus suggesting that the mesenchymal cells capable of regenerating the attachment apparatus may have their origin in the intact PDL.In conclusion, the present findings indicate that (a) the reformed PDL displayed a similar expression of vimentin to the intact (original) PDL, and (b) the cells capable of regenerating new PDL and new cementum appear to be of mesenchymal origin and their source may be in the intact PDL. [Copyright &y& Elsevier]

Examines the prevalence of oxytalan fibers in human guide tissue regenerated (GTR) periodontal ligament. Effectiveness of the treatment of bioresorbable membrane based on GTR-principle; Methodology of the treatment; Assessment on the function of oxylan fibers.

The objective of this investigation was to determine the microbial generation time during early human supragingival plaque formation. On 2 occasions, 13 participants refrained from all oral hygiene measures for periods of 1, 2, 4, 8, 24 and 72 h. Plaque was sampled from defined areas of the teeth 13, 14, 15, 23, 24 and 25. Two independent methods were used to estimate the total number of viable cells: colony-forming units BCVF, total bacterial counts (BC) as enumerated by microscopic examination, and the percentage of vital bacteria using a vital fluorescence technique (VF) were recorded. The total number of vital microorganisms was calculated by BCVF (= BC × VF). The generation time based on either colony-forming units or BCVF increased significantly with plaque age. During the first interval (1-4 h), the microbial multiplication took slightly less than 1 h. After the establishment of a more mature plaque (24 72 h), the replicating time was between 12.5 h (BCVF) and 14.8 h (colony-forming units). It was concluded that the microbial generation time recorded at the initial stages of plaque formation is considerably lower than that found in older plaque. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the effect of repeated subgingival oxygen irrigations in previously untreated deep periodontal pockets. 112 pockets &ges;4 mm were selected in 14 subjects Probing attachment level arid bleeding on probing were recorded, as well as the presence of disease-associated microorganisms within the pocket. Subsequently, the pockets were irrigated with gaseous oxygen 1 × a week during a continuous 8-week period. Irrigations with nitrogen served as control. The re-evaluation of all clinical and microbiological parameters at the end of study revealed that repeated oxygen insufflations resulted in a significant clinical improvement of the periodontal baseline conditions superior to the one found in the control. [ABSTRACT FROM AUTHOR]