Impact of dentine hypersensitivity on oral health-related quality of life in individuals receiving supportive periodontal care.

AIM: To determine the prevalence and impact of dentine hypersensitivity (DH) on oral health-related quality of life (OHRQoL) in individuals receiving supportive periodontal care (SPC). MATERIALS AND METHODS: One hundred and two adults receiving SPC were recruited for a cross-sectional study. Subjects were categorized into those who self-reported DH (DH1) or did not (DH0). Impact of DH on OHRQoL was assessed using the Chinese Condition-Specific Oral Impact on Daily Performance questionnaire (CS-OIDP). Evaluation of DH included tactile-stimulation followed by air-blast, and recorded using a Visual Analogue Scale (VAS). RESULTS: Sixty-one (59.8%) subjects self-reported DH with mean air-blast VAS score of 29.4 ± 21.3 mm and mean tactile-stimulation VAS score of 10.9 ± 14.7 mm. Fifty (49%) subjects reported impact on OHRQoL (mean CS-OIDP score = 4.7 ± 6.3). The most affected performance was cleaning the mouth (35.3%). Positive expression of DH and worse OHRQoL were associated with higher air-blast and tactile-stimulation VAS scores, and use of desensitizing agents. The minimally important difference (MID) in CS-OIDP scores was 2.0 points. Approximately 30% of the subjects reported CS-OIDP scores above the MID. CONCLUSIONS: Dentine hypersensitivity affects OHRQoL in patients undergoing SPC. The extent of impact was associated with severity of DH.

Perception of Non-surgical Periodontal Treatment in Individuals Receiving or Not Receiving Local Anaesthesia.

PURPOSE: Patients might refuse the offer of local anaesthesia (LA) administration prior to dental treatment. This study investigates subjective discomfort perception during non-surgical mechanical periodontal therapy delivered with or without LA. MATERIALS AND METHODS: Sixty patients with mild to moderate chronic periodontitis and prior periodontal debridement experience were randomly enrolled in nonsurgical therapy of a quadrant with or without LA administration. Patients were free to comply or not with the allocated LA arrangement. Visual analogue scales (VAS) of discomfort perception at various stages of the treatment as well as overall satisfaction were recorded. Demographic, psychosocial and periodontal parameters were recorded. RESULTS: Thirty-one patients undergoing nonsurgical periodontal therapy not receiving (LA-) and 29 participants receiving LA (LA+) were studied. Compared to LA- patients, LA+ individuals perceived less discomfort during treatment and reported less dental anxiety (p<0.05). Lower overall treatment satisfaction was associated with prior unpleasant periodontal experience (p=0.047). Overall, debridement discomfort was associated with not receiving LA, noncompliance with the pain control regimen allocated, longer treatment duration, greater gingival inflammation and a higher percentage sites with probing pocket depths≥5 mm (p<0.05). CONCLUSION: Clinicians should be aware that patients who refuse LA can experience higher dental anxiety and therefore may require various pain control strategies for comfort during nonsurgical periodontal therapy, which, if not employed, can lead to less periodontal treatment satisfaction.

Survival of molar teeth after resective periodontal therapy--a retrospective study.

AIM: To study outcomes of molar teeth after resective therapy performed with the intention to prolong the lifespan of teeth having one or more unsaveable roots, and without which tooth extraction would be inevitable. MATERIAL AND METHODS: Clinical records of 149 subjects who had undergone resective therapy were retrieved. Demography and dental history were recorded, and a recall examination was undertaken. Cox regression models were performed. RESULTS: Of the 149 resective therapies, 132 (88.6%) were performed for periodontal reasons. Eighty-nine (59.7%) teeth subjected to resective therapies had been extracted by the time of recall (mean 10 years post-resection). The median survival period was 74 months. Factors significantly associated with shorter survival duration of teeth subjected to resective therapy were: age at resective therapy; pre-operative radiographic bone height of the remaining root(s) <50%; pre-treatment mobility II or above and not being splinted to neighbouring teeth nor incorporated as a bridge abutment. CONCLUSION: There was increased risk of tooth loss with increasing age at resection, grade II mobility or above, and reduced pre-operative radiographic bone heights around roots to remain. Splinting of a resected tooth to neighbouring teeth appeared to confer a protective effect towards its survival.

Non-surgical periodontal therapy improves oral health-related quality of life.

AIM: The influence of non-surgical periodontal therapy on oral health-related quality of life (OHQoL) was investigated. MATERIALS AND METHODS: Sixty-five Chinese adults (25 men, mean 47.4 years) with moderate-to-advanced chronic periodontitis were recruited. All received oral hygiene instructions (OHI) and non-surgical periodontal treatment in a quadrant-wise approach, followed by recalls at 1, 3, 6, 9 and 12 months post treatment, when OHI and prophylaxis were repeated. Clinical parameters were recorded, and oral health impact profile short-form (OHIP-14S) was administered at all time points. RESULTS: Moderate-to-deep sites (≥4 mm) decreased from 31.0% to 3.0% at 12 months post treatment (p < 0.005) which corresponded well with reductions in plaque, 72.8% to 25.4% (p < 0.005) and bleeding on probing, 86.3% to 32.0% (p < 0.005). Median OHIP-14S scores gradually reduced from 17 at baseline to 14 over the first 6 months and remained plateaued at 12-month post treatment (p < 0.005). Improvements in subdomains of physical pain, psychological discomfort and psychological disability accounted for the changes. CONCLUSION: This study demonstrates that OHQoL, in particular, pain and psychological subdomains, improvement was associated with non-surgical periodontal therapy responses. Clinicians could capitalize upon the positive psychological OHQoL impacts of mechanical periodontal treatment for subsequent patient-centred motivation during maintenance therapy.

Graduates' perceived preparedness for dental practice from PBL and traditional curricula.

The objective of this study was to compare dental graduates' perceived preparedness for practice after being educated in a problem-based learning (PBL) curriculum with those who graduated from a traditional undergraduate curriculum, both at the University of Hong Kong. A cohort of graduates from the traditional dental curriculum (1997-2001) and a cohort of graduates from the PBL curriculum (2004-08) rated their self-perceived preparedness for dental practice in fifty-nine aspects of dentistry across nine domains. Perceived preparedness for dental practice was compared at domain and item levels (accounting for multiple comparisons) using chi-square statistics. Both cohorts felt well prepared for the "bread and butter" aspects of dentistry, but less so for specific specialty disciplines. There was no significant difference between PBL and traditional graduates' self-perceived preparedness in eight of the nine domains of dental practice (P>0.05). However, in the area of orthodontics, both cohorts felt ill-prepared for practice and more so among the PBL cohort (P<0.01). For the most part, regardless of curriculum design, these dental graduates perceived themselves to be well prepared for dental practice.

Periodontal conditions in elderly men with and without osteoporosis or osteopenia.

BACKGROUND: The purpose of this case-control study is to investigate the periodontal conditions in elderly men with and without osteoporosis or osteopenia and to determine their possible association with periodontal destruction. METHODS: A total of 200 community-dwelling Chinese males (age range: 69 to 78 years; mean ± SD age: 71.9 ± 3.3 years) were recruited from the Jockey Club Center for Osteoporosis Care and Control, The Chinese University of Hong Kong, including 67 subjects with osteoporosis, 66 subjects with osteopenia, and 67 age-matched normal control subjects based on bone mineral density at the hip, spine, and whole body measured by dual-energy x-ray densitometry. All subjects were interviewed using questionnaires and received a full-mouth periodontal examination. RESULTS: Subjects with osteoporosis exhibited a significantly higher percentage of sites with clinical attachment loss (AL) > or= 6 mm compared to subjects with osteopenia (P <0.05); subjects with osteoporosis also showed a greater percentage of sites with interproximal gingival recession (GR) > or = 5 mm than did control subjects (P <0.05) after excluding smokers. Subjects with osteoporosis were more likely (odds ratio = 3.3; P <0.05) to exhibit interproximal GR > or = 5 mm than were control subjects. Osteoporosis remained significantly associated with severe clinical AL and interproximal GR after adjusting for age, supragingival plaque, and number of teeth lost. CONCLUSION: This study suggests that osteoporosis is associated with severe clinical AL and interproximal GR in elderly Chinese men.

Effects of smoking on healing response to non-surgical periodontal therapy: a multilevel modelling analysis.

AIM: To investigate the factors predicting non-surgical periodontal treatment responses using multilevel multiple regression. MATERIAL AND METHODS: Forty men (mean 45.6 years) were recruited; 20 were smokers. A 12-month reduction in probing pocket depth (PPD) and gain in probing attachment level (PAL) of 5814 sites were analysed, with 594 being initially diseased sites (initial PPD> or =5 mm). RESULTS: Variance Component models showed that site-level variations contributed about 70-90% of the total variance. About a 10% reduction of the total variations of PPD reduction in initially diseased sites was achieved with the inclusion of the 10 predictors in the multilevel multiple regression. Multilevel multiple regression showed that three predictors, subject level: non-smokers; tooth-level: anterior teeth; and site level: sites without plaque at baseline, were significantly associated with a greater reduction in PPD in initially diseased sites over the 12-month study period (p<0.05). No consistent predictor was found for PAL gain. CONCLUSION: Multilevel analysis was applied on periodontal treatment response data. Smokers showed less favourable PPD reduction at deep sites after non-surgical periodontal therapy.

Toll-like receptors 2 and 4 gene polymorphisms in a Chinese population with periodontitis.

OBJECTIVES: Polymorphisms for toll-like receptor (TLR) 2 gene (Arg677Trp, Arg753Gln) and TLR4 gene (Asp299Gly, Thr399Ile) that are associated with impaired lipopolysaccharide (LPS) signal transduction have recently been described. The present study aimed to investigate the relationship between TLRs 2 and 4 gene polymorphisms and periodontitis in a Chinese population. METHOD AND MATERIALS: Forty patients with generalized aggressive periodontitis, 50 patients with chronic periodontitis, and 100 periodontally healthy controls were recruited. All these subjects were of Han Chinese ethnicity. Genomic DNA was extracted from whole-blood samples. TLRs 2 and 4 genes were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) with respective restriction endonucleases. The alleles were detected by polyacrylamide gel electrophoresis and visualized with ethidium bromide. RESULTS: Heterozygosity for the TLR2 Arg677Trp polymorphism was found in all subjects. The TLR2 Arg753Gln mutant allele was not found in periodontitis patients, while a heterozygous frequency of 6% (6 of 100) was detected in the controls. The TLR4 Asp299Gly and Thr399Ile mutant alleles were not found in any of the subjects. CONCLUSION: TLR2 Arg753Gln polymorphism may not be associated with aggressive or chronic periodontitis in the Chinese population. The prevalence of TLR2 Arp677Trp polymorphism seemed to be rather high, while that of TLR4 Asp299Gly and Thr399Ile polymorphisms seemed to be rather low in the Chinese population, which did not permit any conclusion regarding its effects on periodontitis.

Non-surgical periodontal therapy with adjunctive chlorhexidine use in adults with down syndrome: a prospective case series.

BACKGROUND: Subjects with Down syndrome (DS) experience a high prevalence of periodontal disease, and the management of this disease in subjects with DS is a challenge for oral health care providers. The purpose of this case series was to follow the periodontal healing response changes over a 12-month period after non-surgical mechanical periodontal therapy with the adjunctive use of chlorhexidine and monthly recalls in adults with DS who presented initially with chronic periodontitis. METHODS: Twenty-one subjects with DS (14 males and seven females; 25.3 +/- 5.5 years of age) with reported mild-to-moderate learning disabilities and chronic periodontitis were recruited and treated by non-surgical mechanical periodontal therapy (followed by monthly recalls) and the adjunctive use of chlorhexidine gel for toothbrushing and chlorhexidine mouthwash twice daily. Clinical data were recorded. RESULTS: After 12 months of non-surgical mechanical periodontal therapy, the mean percentage of sites with plaque decreased from 84.1% to 23.6%, and the mean number of sites with bleeding on probing decreased from 82.1% to 29.5%. Mean probing depth decreased from 3.2 to 1.8 mm, with a mean clinical attachment level gain of 0.6 mm. CONCLUSIONS: Satisfactory healing responses were achieved following non-surgical mechanical periodontal therapy with the adjunctive use of chlorhexidine and monthly recalls in adults with DS with chronic periodontitis and mild-to-moderate learning disabilities. Such a treatment regimen seems appropriate and beneficial for adults with DS and chronic periodontitis.

Health behaviour, metabolic control and periodontal status in medically treated Chinese with type 2 diabetes mellitus.

OBJECTIVE: Relationships between demographic, health behaviour and diabetes mellitus (DM) parameters and periodontal status were assessed among a group of nonsmoking, low-income, middle-aged to elderly medically treated Hong Kong Chinese subjects with type 2 diabetes mellitus (DM). MATERIALS AND METHODS: 193 Chinese, dentate, type 2 DM patients (56.5 +/- 9.0 years; recorded DM duration 7.0 +/- 5.2 years) attending a charity hospital specialist clinic were surveyed. Subject demography, periodontal status, Body Mass Index (BMI), DM control, serum TNF-alpha level and general health behaviour (GHB) were recorded. RESULTS: Periodontitis was prevalent (80.3% of subjects with PPD > or = 5 mm and 65.8% subjects with full-mouth mean PAL > 3.0 mm). Mean HbA1c, fasting plasma glucose and BMI were 7.6 +/- 1.6%, 8.2 +/- 2.9 mmol/L and 25.4 +/- 3.7 kg/m2 respectively. Serum TNF-alpha level was similar to the reported Chinese population norm. Full-mouth mean clinical attachment level was associated with DM duration while full-mouth mean probing pocket depth was associated with GHB (p < 0.05). The Gingival Index, was greater in men, and associated with higher HbA1c% and lower education attainment (p < 0.03). CONCLUSION: In this group of non-smoking, predominantly low-education background, overweight, Chinese subjects with fairly well-controlled type 2 DM, periodontal attachment loss and periodontal disease appeared to be associated with DM duration and health behaviour. Health care providers should consider paying more attention to improving the GHB of their type 2 DM patients with long DM duration. DM subjects with a low educational background, having higher HbA1c% and males are more likely to experience gingival inflammation.

Oral health status of adults with Down syndrome in Hong Kong.

The aim of this survey was to study the oral health status of Hong Kong Chinese adults with Down syndrome (DS). Sixty-five community-dwelling adults with DS (aged 17 to 42 years, 26.8+/-6.4) and age- and gender-matched controls attending a dental hospital were included in a cross-sectional survey. The subjects with DS had fewer filled (2.4+/-4.6 vs. 2.7+/-3.1, p=0.017) and fewer decayed (1.1 2.5 vs. 1.7+/-2.4, p=0.007) teeth than the control subjects. Significantly more peg-shaped maxillary lateral incisors and retained primary teeth (p<0.001) were observed in subjects with DS, compared to the control subjects. Adults who had DS had a significantly higher percentage of surfaces with detectable plaque (81.5+/-19.1 vs. 61.9+/-16.0, p<0.001) and a higher percentage of sites with bleeding on probing (76.3+/-25.8 vs. 55.6+/-21.4, p<0.001). A higher proportion of subjects with DS showed one or more occurrences where probing pocket depth was > or =6mm than control subjects (49% vs. 24.5%, p<0.021). In conclusion, while having fewer caries, Hong Kong Chinese adults with DS had poorer periodontal health than age- and gender-matched control subjects.

Repeated oral hygiene instructions alone, or in combination with metronidazole dental gel with or without subgingival scaling in adult periodontitis patients: a one-year clinical study.

The aims of the present study were to evaluate the clinical efficacy of, and to monitor microbiologically, repeated oral hygiene instructions alone or in combination with metronidazole 25% gel or subgingival scaling with or without metronidazole gel in treatment of new, residual or recurrent periodontal pockets in previously treated adult periodontitis patients. Ten suitable patients were included in this randomized single-blind clinical study with an intra-individual design. Clinical parameters were measured before and at 1, 3, 6, 9 and 12 months after treatment. Subgingival plaque samples were taken at every examination from one selected site in each quadrant. Smears from plaque samples were silver-stained and differential counting was performed under light microscopy at 1000X magnification. Four treatment modalities: (i) oral hygiene instruction (OHI) alone; (ii) OHI and metronidazole dental gel; (iii) OHI and subgingival scaling; (iv) OHI and subgingival scaling plus metronidazole gel, were randomly assigned to one quadrant of each patient. At the 12-month examination, the mean reductions in probing pocket depth were 2.6 mm after OHI alone, 2.8 mm after OHI and metronidazole gel, 3.3 mm after OHI and subgingival scaling and 2.6 mm after oral OHI and subgingival scaling plus metronidazole gel. The mean gains in probing attachment level were 2.2 mm, 1.9 mm, 2.7 mm and 1.6 mm, respectively. Although there were statistically significant differences in treatment responses between some treatment modalities at some time points, these were not considered to be clinically significant. Differential counts showed a shift towards a healthy microflora in response to all treatment modalities. From the 12-month results, it was concluded that the metronidazole 25% gel produced positive effects on the clinical parameters and on the subgingival plaque microbiological composition in new, residual or recurrent pockets in previously treated chronic periodontitis patients. However, the metronidazole gel alone or in combination with scaling does not seem to have any additional clinically significant therapeutic effects over and above those derived from improved oral hygiene resulting from monthly recalls, with or without subgingival scaling.

Periodontal diseases in Asians.

Asia encompasses three of the four most populous nations in the world (China, India and Indonesia), accounting for nearly two-fifths of the worlds' total population. Over half of the world's population now inhabits Asia, which by definition includes countries of the Middle East and some former Socialist Soviet Republics. There has been a generally held view that Asians are particularly susceptible to periodontitis. The aim of this review is to consider the reasons for this view having become entrenched and to examine the evidence on which it could have been established and sustained. This view of a particularly high prevalence of periodontal diseases in Asians appears in retrospect to have originated from early epidemiological studies using an index system which gives weight to gingivitis and moderate periodontitis resulting from poor oral hygiene and calculus deposition, very commonly encountered in Asian populations. Studies that have been conducted comparing Asians immigrants with native Caucasians in industrialized northern hemisphere nations broadly concluded that Asians displayed worse periodontal conditions than Caucasians. Similarly, a classic study comparing Norwegian males with Sri Lankan Tamil males demonstrated worse periodontal conditions in the Asian males. A recent review (Albander and Rams, 2002) has stated that those of African origin display the highest prevalence of periodontitis followed by Hispanics and Asians. Studies of the natural history of periodontal disease in Asians, of perio-dontopathogens in Asians, of risk for periodontal destruction, and of reasons for extraction do not appear to explain increased susceptibility of Asians to periodontal destruction. Poor oral hygiene and calculus deposits are widespread, however. Traditional assessments of periodontitis focus on destruction of the periodontal attachment in terms of attachment loss and probing pocket depths, with no consideration being given to the morphological features of the dentition from which the periodontal attachment is being lost, features that may predispose to or complicate the management of periodontal destruction. The Mongoloid dentition shows a high prevalence of such features, which adds a further dimension to the consideration of periodontal diseases among many Asian peoples. Appropriate strategies for the prevention and management of periodontal disease should focus upon improvements in the oral hygiene situation in the diverse continent of Asia.

Tooth loss in treated periodontitis patients responsible for their supportive care arrangements.

AIM: To identify risk indicators associated with tooth loss and periodontitis in treated patients responsible for arranging supportive periodontal care (SPC). MATERIALS AND METHODS: Ninety-seven Chinese subjects (34-77 years) who showed favourable responses to periodontal therapy provided in a teaching hospital 5-12 years previously were recalled. They were advised to seek regular SPC on discharge. Background information, general health status, smoking, oral hygiene habits, follow-up dental care, tooth loss, and periodontal parameters were investigated. Multiple regression analysis was performed. RESULTS: Two hundred and fifty-six teeth had been lost, 195 because of self-reported periodontal reasons. Up to 26.8% sites were with pockets > or =6 mm. Positive correlations were found between total/periodontal tooth loss and (i) smoking pack-years, (ii) time spent on oral hygiene, (iii) years since therapy's conclusion, (iv) age, and negative correlations with (v) inter-dental brush use, and (vi) education levels. Tooth loss by arch was correlated with wearing of removable partial denture in that arch. Percentage sites with pockets > or =6 mm were significantly negatively correlated with percentage sites without bleeding on probing. CONCLUSIONS: Smokers, more elderly patients, removable partial denture wearers, and patients with lower education levels or not using inter-dental brushes ought to be targeted for clinic-based SPC.

Association of matrix metalloproteinase-1 promoter polymorphism with generalized aggressive periodontitis in a Chinese population.

BACKGROUND: A single nucleotide polymorphism in the promoter region of -1607 bp of the human matrix metalloproteinase-1 (MMP-1) gene has been found to be associated with an increased risk of various inflammatory diseases and cancer metastasis. OBJECTIVES: The present study aimed to examine the distribution of MMP-1 genotypes in a group of Chinese subjects with generalized aggressive periodontitis and a group of periodontally healthy subjects, and to evaluate the possible association of the MMP-1 promoter polymorphism with aggressive periodontitis. METHODS: Genomic DNA was obtained from whole blood samples in 40 Chinese subjects with generalized aggressive periodontitis and 52 periodontally healthy subjects as controls. MMP-1 promoter fragment was amplified by polymerase chain reaction, and the polymorphisms were analyzed by restriction endonuclease cleavage. The alleles were detected by polyacrylamide gel electrophoresis and visualized with ethidium bromide. RESULTS: The detection frequency of 2G allele was significantly higher in the subjects with generalized aggressive periodontitis (68.7%) than in the control subjects (49%) (p < 0.01). The genotype of 2G/2G was found in 52.5% of the patients, which was significantly greater than that of control subjects (23.1%) (p < 0.05). CONCLUSION: The present study suggests that a single nucleotide polymorphism in the MMP-1 promoter region of -1607 bp may be associated with generalized aggressive periodontitis in Chinese population.

A regimen of systematic periodontal care after removal of impacted mandibular third molars manages periodontal pockets associated with the mandibular second molars.

AIM: This randomized, single-blinded control trial investigated the local effects of periodontal care on the mandibular second molar delivered during and after impacted third molar surgical extraction. METHOD: Thirty subjects (50% male, 32.1+/-7.8 years) out of 35 enrolled, with a mesio-angular impacted mandibular third molar, having probing pocket depth (PPD) >5 mm at adjacent second molar distal, and crestal radio-lucency between the two teeth, completed the study. Oral hygiene instruction, scaling and caries stabilization were performed before surgery. Controls (n=16) had their third molar extracted followed by standard socket debridement. Test group subjects (n=14) received the same treatment, except that before wound closure the operator was informed of the group allocation and ultrasonic root debridement on the second molar was performed, followed by a three-visit plaque control programme. RESULTS: Six months post-extraction, statistically significantly (p<0.007) better plaque control and shallower probing depths were observed at test second molars' distal (%plaque=21; PPD=3.2+/-1.2 mm) than at control second molars (%plaque=88; PPD=5.2+/-0.7 mm). CONCLUSIONS: The periodontal interventions investigated prevented residual pockets on periodontally involved second molars 6 months after ipsilateral impacted mandibular third molar removal.

Characterization of Actinobacillus actinomycetemcomitans isolated from young Chinese aggressive periodontitis patients.

OBJECTIVE: This study characterized Actinobacillus actinomycetemcomitans isolates from young Chinese aggressive periodontitis patients. METHODS: Subgingival plaque samples (two/subject) were collected from diseased subjects < 25 years old (n = 9, mean age 21.1 +/- 1.6 years) and age-matched periodontitis-free controls (n = 47, mean age 22.0 +/- 1.1 years). Selective and anaerobic culture were used. The serotype, leukotoxin gene (ltx) operon promoter and the cytolethal distending toxin (cdt) genes complex of the A. actinomycetemcomitans isolates were investigated. Effects of the isolates on non-keratinizing periodontal ligament epithelial cells monolayer were studied. RESULTS: Diseased subjects had significantly higher full-mouth bleeding score (p = 0.002) and total viable counts from plaque samples (7.2 x 10(6) vs. 2.1 x 10(5) CFU/paperpoint, p < 0.005). A. actinomycetemcomitans was isolated from 67%/56% or 6%/4% of diseased or controls subject/sites, respectively (p < 0.001). The proportion of A. actinomycetemcomitans isolatable from aggressive periodontitis or periodontitis-free associated subgingival plaque was low (0.7% vs. 0.1%, p < 0.02). The serotype of the isolates was characterized. All isolates possessed 652-like ltx gene promoter and all but one serotype c isolate from a diseased patient had intact cdtABC genes. That particular strain appeared to confer the least cellular damages on periodontal ligament epithelial monolayer compared to others. CONCLUSION: This preliminary study confirmed the notion of increased prevalence and quantity of A. actinomycetemcomitans associated with aggressive periodontitis in young patients. The overall ltx promoter and cdt characteristics of the A. actinomycetemcomitans isolates, however, were similar among the diseased and control groups. A strain lacking the cdtABC gene appeared to be less damaging to a periodontal ligament epithelial cell model. Further studies therefore are warranted to clarify the pathogenic role and potentials of A. actinomycetemcomitans in aggressive periodontitis.

Microflora cultivable from minocycline strips placed in persisting periodontal pockets.

OBJECTIVE: The microflora that develops on minocycline strips, used as an adjunct in non-surgical periodontal therapy was studied. DESIGN AND METHODS: Minocycline (1.4 mg in polycaprolactone vehicle) and control strips were applied into all residual pockets (PD > or = 5mm, > or =2 pockets/subject) of patients with chronic periodontitis 1 month after a course of non-surgical periodontal therapy. Strips were inserted and retained for 3 days, changed to new strips for 3 more days and then removed. Strips were recovered from 14 (eight test, six control) of the 34 participants at day 0 (strip inserted, left for 30 s, removed), days 3 and 6, for (i) anaerobic culture, (ii) coliforms culture, using MacConkey agar, (iii) yeast culture, using Sabouraud's dextrose agar. RESULTS: The mean anaerobic cfu/strip (x10(5); control/test) were 2/6, 24/2, 11/2 at days 0, 3 and 6, respectively (P > 0.05). The corresponding mean proportion of Gram-negative rods and fusiforms were 27%/21%, 27%/15% and 55%/8%. The proportions of Gram-negative rods on test strips by day 6 were significantly reduced (P < 0.05). A significantly increased prevalence of Streptococcus mitis biovar 1 was found on spent test strips (control versus test; 0% versus 38%, Fisher exact test, P = 0.01). Coliform prevalence at days 0, 3 and 6 on control/test strips were 0/13%, 50%/38% and 50%/13%. Yeasts were occasionally isolated. CONCLUSIONS: The findings indicated that the minocycline strips but not the control strip supported a microbial colonisation compatible with periodontal health by day 6.