Union, employer and compensation system gaps and failures: Workers with injuries perceptions

BACKGROUND

Workers who suffered a workplace injury and submitted a claim with the compensation board in Ontario often faced economic and non-economic costs that provoked depressive feelings, family strain, financial strain, and feelings of diminished self-worth.

OBJECTIVE

This qualitative descriptive study aimed to understand the perceived gaps and failures associated with the support systems (e.g., union, compensation and employer) that were in place to assist some male underground workers in Sudbury, Ontario, Canada, who had suffered a workplace injury and had a compensation claim.

METHODS

Twelve in-depth, in-person, individual, semi-structured interviews were conducted and data were transcribed verbatim and anonymized at the time of transcription. Data analysis followed Braun and Clarke's guidelines for thematic analysis.

RESULTS

Themes that emerged include: unfair and inadequate recognition of an injury; limited communication with stakeholders involved with their claim, including claim adjudicators, challenges when returning to work, and compensation claim system barriers.

CONCLUSIONS

Cooperation, collaboration, knowledge transfer, and decreased power imbalances could help to reduce the economic and non-economic strain felt by a worker with an injury. Additionally, a government-funded third-party advocate who knows the medical system, union contracts, the workers' compensation system, and employer policies and practices could act on behalf of an injured worker.

Novel Tools in Determining the Physiological Demands and Nutritional Practices of Ontario FireRangers during Fire Deployments

INTRODUCTION

The seasonal profession of wildland fire fighting in Canada requires individuals to work in harsh environmental conditions that are physically demanding. The purpose of this study was to use novel technologies to evaluate the physiological demands and nutritional practices of Canadian FireRangers during fire deployments.

METHODS

Participants (n = 21) from a northern Ontario Fire Base volunteered for this study and data collection occurred during the 2014 fire season and included Initial Attack (IA), Project Fire (P), and Fire Base (B) deployments. Deployment-specific energy demands and physiological responses were measured using heart-rate variability (HRV) monitoring devices (Zephyr BioHarness3 units). Food consumption behaviour and nutrient quantity and quality were captured using audio-video food logs on iPod Touches and analyzed by NutriBase Pro 11 software.

RESULTS

Insufficient kilocalories were consumed relative to expenditure for all deployment types. Average daily kilocalories consumed: IA: 3758 (80% consumption rate); P: 2945±888.8; B: 2433±570.8. Average daily kilocalorie expenditure: IA: 4538±106.3; P: 4012±1164.8; B: 2842±649.9. The Average Macronutrient Distribution Range (AMDR) for protein was acceptable: 22-25% (across deployment types). Whereas the AMDR for fat and carbohydrates were high: 40-50%; and low: 27-37% respectively, across deployment types.

CONCLUSIONS

This study is the first to use the described methodology to simultaneously evaluate energy expenditures and nutritional practices in an occupational setting. The results support the use of HRV monitoring and video-food capture, in occupational field settings, to assess job demands. FireRangers expended the most energy during IA, and the least during B deployments. These results indicate the need to develop strategies centered on maintaining physical fitness and improving food practices.

Comparing para-rowing set-ups on an ergometer using kinematic movement patterns of able-bodied rowers

While numerous studies have investigated the biomechanics of able-bodied rowing, few studies have been completed with para-rowing set-ups. The purpose of this research was to provide benchmark data for handle kinetics and joint kinematics for able-bodied athletes rowing in para- rowing set-ups on an indoor ergometer. Able-bodied varsity rowers performed maximal trials in three para-rowing set-ups; Legs, Trunk and Arms (LTA), Trunk and Arms (TA) and Arms and Shoulders (AS) rowing. The handle force kinetics of the LTA stroke were comparable to the values for able-bodied literature. Lumbar flexion at the catch, extension at the finish and total range of motion were, however, greater than values in the literature for able-bodied athletes in the LTA set-up. Additionally, rowers in TA and AS set-ups utilised more extreme ranges of motion for lumbar flexion, elbow flexion and shoulder abduction than the LTA set-up. This study provides the first biomechanical values of the para-rowing strokes for researchers, coaches and athletes to use while promoting the safest training programmes possible for para-rowing.

Long-term tooth loss in periodontally compromised but treated patients according to the type of prosthodontic treatment. A retrospective study

If prosthodontic treatment is considered after periodontal therapy, the questions arise i) does prosthodontic treatment affect the treatment outcome of the dentition in general and ii) which type of prosthesis is related to best treatment outcome of abutment teeth? Our goal was to compare long-term tooth loss after comprehensive periodontal therapy in patients with or without prosthodontic treatment. Ninety patients' charts with a total of 1937 teeth who had received comprehensive periodontal treatment 5-17 years ago by the same periodontist were retrospectively evaluated. Sixty-five patients received fixed dental prostheses (FDP; n = 29) and/or removable partial dentures anchored with clips (RPDC; n = 25) or double crowns (RPDD; n = 25). Twenty-five patients were also periodontally compromised but treated without prosthodontic treatment and served as a control group. A total of 317 teeth and 70 abutment teeth were lost during 9.7 ± 4.1 years of observation. Thereof, 273 teeth and 48 abutment teeth were lost due to periodontal reasons. Mean tooth loss amounted to 1.2 ± 1.5 (controls) and 4.4 ± 3.4 (partial dentures). Abutment tooth loss was 0.4 ± 1.1 (FDP), 1.0 ± 1.2 (RPDC) and 1.3 ± 1.0 (RPDD). Poisson regressions identified prosthodontic treatment, age, socio-economic status, diabetes mellitus, mean initial bone loss and aggressive periodontitis as factors significantly contributing to tooth loss. Age, diabetes and non-compliance contributed to abutment tooth loss. Not considering biomechanical factors, patients with prosthodontic reconstructions under long-term supportive periodontal therapy were at higher risk for further tooth loss than patients without prostheses. Not only the type of partial denture but also the patient-related risk factors were associated with abutment tooth loss.

Postural implications of obtaining line-of-sight for seated operators of underground mining load-haul-dump vehicles

Operators of load-haul-dump (LHD) vehicles use awkward postures that may be held statically and at extreme ranges of motion for long shift periods to spot hazards in underground mining. This study examined postural variables associated with three amounts of seat rotation intended to maximize line-of-sight during forward driving. Three different models, representing the 1st, 50th and 99th percentile male for height and weight, were positioned with appropriate hand and foot constraints in the virtual LHD cab modelled in Classic JACK v4.0. A total of 15 virtual movement strategies were developed to model the postural behaviour of typical workers and each virtual subject was tested, first with the seat in a neutral 0 degrees position and then with it rotated counter-clockwise to 20 degrees and 45 degrees . Results revealed that reductions in trunk rotation, trunk lateral bend and neck rotation were associated with the seat rotation intervention. The general relationship observed was that as seat rotation increased, view of critical visual attention locations and visible line-of-sight area increased while postural load variables decreased. For the most part, 20 degres of seat rotation was beneficial but 45 dgrees produced significantly greater changes to postural load and visible visual attention locations.

Gingivitis in young adults with Actinobacillus actinomycetemcomitans

High intraoral load of A. actinomycetemcomitans in subjects with no or minimal periodontal disease may induce subtle changes in clinical periodontal conditions. The aim of the present study was to compare, at a site level, clinical conditions in two groups of young adults with plaque-induced gingivitis. In one group, more than 20% subgingival sites harboured cultivable A. actinomycetemcomitans (n=9), whereas in the other group, the organism was present in 20% or fewer subgingival plaque samples (n=8). Whereas no overt differences in clinical conditions could be ascertained, on average, the association between the presence of subgingival plaque and bleeding upon probing was considerably stronger (Mantel-Haenszel's common odds ratio RMH and 95% confidence interval 3.903, 2.951-5.165, P<0.001) in subjects with only a few subgingival sites harbouring A. actinomycetemcomitans as compared to subjects with a widespread intraoral distribution of the organism (R(MH)=1.637, 1.226-2.184, P<0.001). Since the proportion of sites not bleeding upon probing in the presence of supragingival plaque was slightly elevated in these subjects, the present findings may suggest a suppressed inflammatory reaction on supragingival plaque in the presence of a pronounced intraoral load of A. actinomycetemcomitans.

Failure of root coverage of shallow gingival recessions employing GTR and a bioresorbable membrane

The aim of the present study was to compare the postsurgical outcome of two different modes of surgical root coverage of predominantly shallow, Class I or II, gingival recessions. Fourteen facial recessions in nine patients were subjected to a coronally repositioned flap in combination with a bioresorbable membrane, and 14 sites in 13 patients were treated with a connective tissue graft employing an envelope technique. Immediately before surgery and after 6 and 12 months, gingival dimensions as well as root coverage and attachment gain were assessed. At baseline, mean recession depths amounted to 2.77+/-1.67 mm and 2.49+/-1.07 mm for patients treated with a bioresorbable membrane and a free connective tissue graft, respectively. Acceptable and stable root coverage of 81% to 82% of baseline recession depth and 78% of its width was achieved by grafting. In contrast, guided tissue regeneration (GTR) resulted in only 50% coverage of recession depth and, after 12 months, only 11% of its width (P < 0.01). Logistic regression revealed that the odds of obtaining success, ie, at least 80% root coverage, were 3.3 times greater in cases treated with a connective tissue graft (P < 0.05). In addition, the odds ratio was 2.3 in cases of recessions below 2.5 mm compared to deeper recessions and 2 at canines compared to premolars. It was concluded that shallow recessions in the 1.5 to 3.5 mm range should not be treated with GTR. In these situations, predictable results are achieved with free connective tissue grafts employing an envelope technique.

Intraoral distribution of Actinobacillus actinomycetemcomitans in young adults with minimal periodontal disease

The aim of the present study was to investigate the intraoral distribution of Actinobacillus actinomycetemcomitans in young adults with minor signs of periodontal disease but harboring the organisms in the oral cavity. 17 healthy volunteers, 20 to 27 years of age, participated. Samples from mucosal surfaces of the oro-pharyngeal cavity and saliva (n = 221) as well as subgingival plaque from every tooth (n =477) were selectively cultivated for A. actinomycetemcomitans. Species identity and presence of the leukotoxin encoding gene, ltxA, were checked by multiplex polymerase chain reaction. Moreover, the leukotoxin promoter region was analyzed. No isolate harbored a 530 bp deletion in the promoter region of the leukotoxin gene, signaling minimally toxic strains. 42.1 +/- 30.4% extracrevicular and 34.4 +/- 29.5% subgingival samples were culture-positive. In extracrevicular samples, the organism could easily be recovered from cheek mucosa (62%), saliva (59%) and the palatal tonsils (41%). Mean log-transformed numbers of A. actinomycetecomitans colony forming units (CFU/ml) in culture-positive material ranged between 1.8 from the hard palate and 2.3 from 10 microl saliva. The highest prevalence in subgingival plaque was observed at maxillary 3rd molars (55%) followed by maxillary lateral incisors (50%) and mandibular 3rd molars (41%). Mean log-transformed counts of CFU/ml ranged between 2.2 at maxillary 3rd molars and 3.4 at upper central incisors. When adjusted for jaw, site and tooth type, the odds of isolating higher numbers of the organism were increased with every mm probing depth by a factor of 1.35 (p <0.05). The odds ratio for bleeding on probing was 1.38. Thus, in this young adult population with minor periodontal disease, A. actinomyetemcomitans was mainly associated with some deviation from gingival health. Of concern might be a minority of subjects (29%) with an extremely wide distribution of the organism in the oral cavity.

Site-specific association between supragingival plaque and bleeding upon probing in young adults

The aim of the present study was to consider supragingival plaque as a risk factor for gingivitis in a group of young adults without destructive periodontal disease. A total of 127 subjects, 17 to 30 years of age, participated. Periodontal probing depth, clinical attachment level as well as bleeding upon probing and supragingival plaque was assessed at 6 sites of every tooth present. The individual odds ratios between plaque and bleeding ranged between 0.237 and 66.6. 23% volunteers had an odds ratio of below 1.2. Only 15% individuals presented with an attributable risk of supragingival plaque for bleeding upon probing of 50% or more. Overall, the odds of bleeding, adjusted for periodontal probing depth, was increased by 67% in the presence of plaque. Large differences were observed at different teeth with the highest odds ratio at mandibular premolars with 2.557 (95% confidence interval 2.033-3.216) and the lowest at maxillary molars with 1.355 (1.161-1.732). It was concluded that there was high interindividual and intraindividual variation of the relative risk for bleeding in the presence of plaque. The observed low overall relative risk has important consequences in educational and health care programmes since the risk of supragingival plaque which is actually attributable for the observed bleeding on probing may be rather small.

Masticatory mucosa in subjects with different periodontal phenotypes

AIMS

The aim of the present investigation was to study thickness of masticatory mucosa and gingival width in subjects with different periodontal phenotypes.

METHODS

Periodontal phenotypes were defined with the aid of cluster analysis of standardised parameters including mean gingival thickness and width as well as ratio of crown width to its length at maxillary canines, lateral and central incisors of 40 young adults with healthy periodontal conditions.

RESULTS

3 groupings could be observed. Clusters A1 and A2 comprised 75% of all subjects. They were characterised by thin gingiva and a slender tooth form. Clusters A1 and A2 were differentiated by gingival width. Cluster B comprised 11 subjects with relatively thick and wide gingiva and a quadratic tooth shape. In general, characteristics of the frontal sextant in the maxilla were also found in other parts of the dentition. Thus, mean thickness of masticatory mucosa as well as gingival width and crown form differed significantly among clusters. In addition, cluster B subjects had a significantly greater mean periodontal probing depth. Multiple linear regression analysis was employed to identify significant factors influencing palatal mucosal thickness. Women had considerably thinner palatal mucosa than men. Furthermore, cluster affiliation had a significant influence on thickness of palatal mucosa. Thickest tissue was found in the premolar region, whereas the mucosa over the root prominence of the first molar represented an anatomical barrier for graft harvesting.

CONCLUSIONS

Thickness of masticatory mucosa strongly depends on gender and the periodontal phenotype.

Thickness of masticatory mucosa

BACKGROUND

The aim of the present study was to assess thickness of all parts of the masticatory mucosa by using an ultrasonic measuring device.

METHODS

A total of 40 periodontally healthy subjects, 19 to 30 years old, took part. Thickness of masticatory mucosa was measured at a maximum of 149 sites in each proband.

RESULTS

Female volunteers had significantly thinner mean masticatory mucosa than males (p<0.01). Mean thickness of facial gingiva ranged between 0.7 mm at canines in the maxilla and central incisors in the mandible and 2.3 mm at 3rd molars in the mandible. In the mandible, thickness of lingual gingiva ranged between 0.9 mm at lateral incisors and 2.3 mm at 3rd molars. Interdental gingiva ranged between 1.0 mm 2.1 mm. With 3 mm or more, on average, palatal masticatory mucosa was thickest in the 3rd molar region and at 2nd premolars at more central locations. 2 regions with comparatively thin palatal mucosa of about 2 mm were identified, namely (i) at central and lateral incisors and (ii) at the prominence of the palatal roots of 1st and 2nd molars. The thickest tissue with more than 4 mm, on average, was observed in the tuberosity and retromolar regions.

CONCLUSIONS

Considerable intra- as well as interindividual variation of thickness of masticatory mucosa could be observed. According to differences in thickness of facial and interdental gingiva, it appears that lining is also an important function of the gingiva in reducing and smoothing the pronounced convexities of the dentoalveolar, i.e., skeletal, complex.

Dynamics of mucosal dimensions after root coverage with a bioresorbable membrane

BACKGROUND

So far, the clinical effects of the placement of a resorbable membrane for guided tissue regeneration have not been studied in humans in great detail. The dynamics of the resorptive processes, in particular, appear to be rather speculative. In the present longitudinal study, specific alterations of the dimensions of the dentogingival mucosa were explored after surgical root coverage by using a bioresorbable membrane and a coronally-repositioned flap.

METHODS

The study population consisted of 14 patients with a total of 31 predominantly shallow, Miller class I, II or III recessions. The thickness of the masticatory and lining mucosa before and after surgical intervention was measured with an ultrasonic device.

RESULTS

Mean (+/-sd) recession depth and width were 2.85+/-1.29 and 4.46+/-1.14 mm, respectively. After 12 months, 51+/-29% of the recession depth (p<0.001) and 13+/-35% of its width (n.s.) were covered. Root coverage seems to be rather defect-type sensitive with best results obtained at canines with relatively shallow recessions. Mucosal thickness was considerably increased after surgery with a gradual decrease during the following 9 months. Thus, thickness of the marginal tissue rose from 0.82+/-0.27 mm to 1.49+/-0.54 mm 3 months after placement of the membrane (p<0.001). After 12 months, a mean thickness of 1.03+/-0.40 mm was observed (p<0.001). Even more pronounced alterations were noted for the alveolar lining mucosa with a threefold increase of thickness 3 months after surgery and a gradual decrease to about 1 mm after 12 months.

CONCLUSIONS

The present results point to the considerable space making capacity of the bioresorbable membrane which probably allows for the ingrowth of a granulation tissue derived from the underlying structures. The gradual decline in mucosal thickness between months 6 and 9 after surgery may be paralleled by the maturation of the granulation tissue while complete resorption of the membrane had been accomplished.

Absence of an especially toxic clone among isolates of Actinobacillus actinomycetemcomitans recovered from army recruits

Actinobacillus actinomycetemcomitans is a major periodontal pathogen which is associated with early-onset and adult periodontitis. The organism has been shown to be widely distributed among dentate, healthy individuals as well. It has been demonstrated that A. actinomycetemcomitans shows great genetic diversity. An especially virulent clone of the organism (JP2-like) with a specific 530-base pair (bp) deletion in the promoter region of the leukotoxin gene has been isolated from localized juvenile periodontitis patients and related subjects of African and African-American origin. The aim of the present study was to examine the presence of this specific clone employing specific oligonucleotide primers in a polymerase chain reaction among 51 isolates of A. actinomycetemcomitans recovered from 201, 18- to 25-year-old recruits with no or minor periodontal disease. In addition, clinical isolates from 37 periodontitis patients were analyzed as well as reference strains ATCC 29524, NCTC 9710, Y4 and JP2. Primers amplifying a specific 285-bp amplification product in the ltxA region of the leukotoxin gene and a specific 547-bp amplification product of 16 S rRNA were used to genetically confirm identification of the organisms. Primers amplifying sequences in the leukotoxin promoter region were used to identify the deletion. Species specific primers definitively identified all A. actinomycetemcomitans isolates. No isolates from army recruits or the reference strains displayed the deletion in the leukotoxin promoter region. However, in the periodontitis group, a 24-year-old individual from Ghana with localized juvenile periodontitis was identified with an intraoral infection with highly toxic A. actinomycetemcomitans (JP2-like). Present results confirm previous observations of absence of a highly toxic clone of A. actinomycetemcomitans among periodontally healthy and diseased Caucasians as well as a possible presence in localized juvenile periodontitis in individuals of African origin.

Ultrasonic determination of thickness of masticatory mucosa: a methodologic study

OBJECTIVE

The aim of the present study was to assess the reliability and validity of ultrasonic measurements of thickness of the masticatory mucosa.

STUDY DESIGN

Eleven periodontally healthy subjects took part. Thickness of the buccal gingiva was assessed midbuccally and interdentally. In the maxilla, the palatal mucosa was measured at every tooth midpalatally, between the first and second molars, and between the second and third molars at each of 3 defined locations 4 mm apart. In the mandible, thickness of the lingual gingiva was measured midlingually as well as interdentally between the first and second molars and between the second and third molars. Thickness of the retromolar mucosa was also assessed. All 1,293 measurements were repeated after 24 hours. Validity of measurements was tested in a porcine model.

RESULTS

Mean (+/- standard deviation) thickness of the midbuccal and midlingual gingiva was 0.99+/-0.52 mm; the measurement error was 0.26 mm. Measurements were well correlated (Pearson's r = .74, P<.001). Mean thickness of the papillary gingiva was 1.19+/-0.53 mm; the measurement error was 0.37 mm (r = .58, P<.001). A lower reliability was observed for palatal measurements of mucosal thickness; mean thickness was 2.36+/-0.87 mm, and measurement error was 0.54 mm (r = .64, P<.001). The validity of measurements was excellent in the 0.5-4.5 mm range.

CONCLUSIONS

Differences in reliability of ultrasonic assessments of mucosal thickness in different parts of the oral cavity may depend on the difficulties of repeatedly measuring at the same location, on varying thickness of the tissues, and on expression of palatal rugae. These problems might be resolved by averaging multiple measurements.

Furcation diagnosis

One of the most important and at present unsolved problems in clinical periodontology is the predictable successful treatment of periodontitis-affected furcations of multirooted teeth. Since several therapeutic approaches are proposed, i.e., conservative, resective or regenerative, a proper diagnosis of these lesions is demanding. The aim of the present article is to review the current information on the impact of a proper diagnosis of a furcational lesion as well as tooth morphology on decision making with regard to different treatment modalities and to emphasize the need for a detailed clinical, radiographical and intraoperative diagnosis of the furcation lesion beyond the usually performed diagnosis of the degree of furcation involvement.

Root coverage employing an envelope technique or guided tissue regeneration with a bioabsorbable membrane

BACKGROUND

Different treatment modalities have been described for root coverage in cases of gingival recession. The aim of the present study was to evaluate the postsurgical outcome of 2 modes of surgical root coverage of predominantly shallow, Class I or II, gingival recessions.

METHODS

Fourteen buccal recession sites in 13 patients were treated with free connective tissue grafts employing a modified envelope technique; 14 sites in 9 patients were subjected to a coronally repositioned flap in combination with a bioabsorbable membrane. Immediately before surgery as well as after 6 months, gingival dimensions, i.e., width and thickness, as well as root coverage and attachment gain, were assessed to the next 0.1 mm employing a caliper, an ultrasonic device, and a pressure calibrated, computerized periodontal probe.

RESULTS

At the outset, mean recession depths amounted to 2.48+/-1.06 and 3.00+/-1.95 mm for patients treated with a free connective tissue graft and a bioabsorbable membrane, respectively. With the former technique, 80+/-24% root surface could be covered after 6 months, while the latter resulted in only 45+/-40% coverage. The contrast in reduction of recession width was even more pronounced (77+/-35% versus 18+/-37%). In both groups, an increase of gingival thickness of 0.6 to 0.7 mm was noticed.

CONCLUSIONS

Small recessions may be covered more predictably with the modified envelope technique. 751.

Prevalence of Mycobacterium avium in slaughter pigs in The Netherlands and comparison of IS1245 restriction fragment length polymorphism patterns of porcine and human isolates

A significant increase in the incidence of caseous lesions in the lymph nodes of slaughter pigs prompted a large-scale investigation in five slaughterhouses in The Netherlands. In total, 158,763 pigs from 2,899 groups underwent gross examination. At least one pig with caseous lesions in the submaxillary and/or mesenteric lymph nodes was observed in each of 154 of the 2,899 groups examined (5%). In total, 856 pigs (0.5%) were affected. As many as five pigs in each of 141 of the 154 positive groups (91.5%) had lymph node lesions. Greater numbers of pigs with affected lymph nodes were found in 13 groups (8.5%). Four pigs had lesions in the kidneys, liver, or spleen. Acid-fast bacteria were detected by microscopic examination of 121 of 292 Ziehl-Neelsen-stained smears of caseous lesions (41%). In a follow-up study, Mycobacterium avium complex (MAC) bacteria were isolated from 219 of 402 affected lymph nodes (54.2%). Ninety-one of the isolated strains were analyzed by restriction fragment length polymorphism (RFLP) typing with insertion sequence IS1245 as a probe. All but 1 of these 91 strains contained IS1245 DNA, indicating that pigs in The Netherlands carried almost exclusively M. avium bacteria and no other bacteria of MAC. Only one pig isolate exhibited the bird-type RFLP pattern. MAC isolates from 191 human patients in The Netherlands in 1996 were also typed by RFLP analysis. Computer-assisted analysis showed that the RFLP patterns of 61% of the human isolates and 59% of the porcine isolates were at least 75% similar to the RFLP patterns of the other group of strains. This indicates that pigs may be an important vehicle for M. avium infections in humans or that pigs and humans share common sources of infection.

Clonal diversity of Actinobacillus actinomycetemcomitans isolates from young adults with minimal periodontal disease

Actinobacillus actinomycetemcomitans is a major periodontal pathogen which is associated with both early-onset periodontitis and adult cases refractory to conventional periodontal therapy, although the organism has also been shown to be widely distributed among dentate healthy individuals. The observed disease status may be associated with a variation in virulence of different strains or clones. The aim of the present study was to analyse genotype distribution as assessed by an arbitrarily primed polymerase chain reaction (AP-PCR) among 51 isolates of A. actinomycetemcomitans recovered from more than 200 young adult recruits with no or minor periodontal disease. In addition, isolates from 25 periodontitis patients as well as reference strains were genotyped. Primers amplifying (i) a specific sequence in the ltxA region, (ii) a specific 16S rRNA sequence and (iii) sequences in the leukotoxin promoter region were used to verify species identity of the strains. Three random oligonucleotide primers were employed to analyse genomic polymorphisms of the organism by means of PCR. A total of 19 genotypes could be distinguished, which were grouped by cluster analysis into 5 major clusters based on genetic similarity and a complete linkage sort. Whereas 3 clusters assembled A. actinomycetemcomitans genotypes isolated from both healthy subjects and periodontitis patients, one cluster containing 4 different genotypes exclusively comprised isolates from healthy or gingivitis subjects. Another cluster with 2 genotypes consisted of strains originating from periodontitis patients (p < 0.05). One strain characterized by a specific 530 bp deletion in the promoter region of the leukotoxin region was identified in a Ghanese patient with localized juvenile periodontitis. It was concluded that there is considerable clonal diversity of A. actinomycetemcomitans strains isolated from healthy or periodontally diseased subjects, and that genetically closely related groups might be associated with health or disease.

Alteration of gingival dimensions in a complicated case of gingival recession

This case report describes possible etiology, treatment, and 2-year outcome of a complicated case of gingival recession in the mandibular anterior dentition. Deep, cleftlike Miller Class I and II recessions at both mandibular canines and all incisors were treated using subperiosteal connective tissue grafts and coronally repositioned flaps. During surgery it was noted that the facial aspects of the roots had lost bone near the apex. After surgery profound alterations of gingival dimension occurred. Mean gingival thickness increased from 0.87 +/- 0.20 mm to 258 +/- 0.65 mm, and width of keratinized tissue increased from 1.34 +/- 0.79 mm to 4.80 +/- 0.97 mm. Periodontal probing depths increased from 1.06 +/- 0.33 mm to 2.74 +/- 0.81 mm, and depth of the recessions was reduced by 56% +/- 5%. Gingival thickness and periodontal probing depth remained stable over the 2 years of observation. Gingival width decreased and the mucogingival border moved a mean 2.5 mm coronally. Creeping attachment resulted in a 74% +/- 24% coverage of recession after 2 years and a gain in clinical attachment of 1.79 +/- 1.56 mm. The present observations point to long-lasting, continuous alterations in the mucogingival region following periodontal surgery in a case of cleftlike Class II recession.

Gingival dimensions after root coverage with free connective tissue grafts

Traumatic injury in the presence of a thin and narrow zone of gingival tissue may lead to gingival recession. Especially in class I and II recessions, root coverage may be accomplished with connective tissue grafts. In order to prevent recurrent recession, altering gingival dimensions width and thickness might be of advantage. In the present study, dimensions of gingiva were followed for 1 year after root coverage with connective tissue grafts. The study population consisted of 18 patients with a total of 28 class I or II recessions. Gingival width and depth of the recession were measured with a caliper, and thickness of the marginal tissue with an ultrasonic device. Periodontal probing depth was determined with a pressure-controlled electronic probe. Mean (+/-sd) recession depth at baseline was 3.1+/-1.4 mm. After 12 months, coverage amounted to 74+/-30%. Width of gingiva rose from 2.1+/-1.0 mm to 3.2+/-1.4 mm, whereas thickness was increased from 0.8+/-0.3 mm to 1.5+/-0.7 mm, on average. No significant alteration of periodontal probing depth was observed but a mean gain of clinical attachment of 1.7+/-1.1 mm was ascertained. In a multiple regression analysis, recession depth and presence of the recession in the maxilla, but not tooth type significantly influenced relative root coverage (R2=0.34, p<0.01). Attachment gain after surgery depended on baseline attachment loss and was negatively influenced by smoking. The present results point to the possibility of doubling gingival thickness after root coverage with connective tissue grafts.

The overall significance of regenerative procedures in the treatment of furcations

A retrospective study examined the frequency of a feasible or remotely possible indication for regenerative therapy of furcation involvement in a large group of periodontally diseased patients. The judgment about the feasibility of the indication was mainly based on results of current randomized controlled clinical trials with regard to tooth type and location of the furcation lesion. Data from 558 patients treated by two periodontists, one experienced and one in training, were analyzed. Furcation involvement of at least one multirooted tooth was found in 40% and 63% of the two dentists' patients. In only 20% and 27% of their patients was there a potential indication for regenerative furcation treatment. Of 1,134 furcation lesions, 180 (15.9%) were conceivably suitable for this procedure. Only 17 sites with a feasible or remotely possible indication were treated in that way. In most cases, conventional furcational treatment (flap surgery with scaling and root planing) was performed.

Gingival phenotypes in young male adults

In a previous study on 42 young adult, periodontally healthy subjects without any attrition, abrasion or crown restoration, gingival thickness (GTH) was determined at facial aspects of premolars, canines and incisors by a novel ultrasonic device. GTH strongly depended on periodontal probing depth, width of gingiva (WG), and tooth type. Whereas the ratio of crown width to its length (CW/CL) was not identified as an explanatory variable, a significant influence of the subject was ascertained. The aim of the present study was to extend these analyses in order to identify subjects with different morphological characteristics of gingiva, i.e., gingival phenotypes. When employing cluster analysis on standardized parameters mean GTH, WG and CW/CL of upper canines, lateral and central incisors, 3 clusters were identified. Cluster A comprised 2/3 of subjects, displaying "normal" GTH, WG and CW/CL. Cluster B (n = 9, 21%) had a significantly thicker and wider gingiva, and a more quadratic form of upper front teeth. A 3rd cluster (cluster C, n = 5, 12%) was identified showing "normal" GTH, high CW/CL, but a narrow zone of keratinized tissue. Some characteristics of gingival phenotype of the upper front tooth region were also found at upper premolars (WG, CW/CL) but in general not at mandibular teeth. Present results clearly indicate evidence for the existence of different gingival phenotypes. Clinical relevance of these observations has to be tested in longitudinal studies.

A longitudinal study of Actinobacillus actinomycetemcomitans in army recruits

During recruiting examinations 201 recruits, 18-25 yr old, were examined for subgingival and extracrevicular Actinobacillus actinomycetemcomitans. The organism was isolated in 55 subjects, most often at low levels. Cluster analysis revealed 3 clusters with no (A, n = 86) or minor (B, n = 92) periodontal disease and low DMF-S, as well as established periodontitis, increased D + DF-S and high DMF-S (C, n = 22). When leaving the 12-months' service, 105 recruits were re-examined (54 cluster A, 41 cluster B, 9 cluster C subjects, 1 recruit who was not clustered). An increase of periodontal probing depth (PPD) of > or = 3 mm at 1 or more sites occurred in 33 subjects: 9 (17%) in cluster A, 16 (39%) in cluster B, 7 (78%) in cluster C and in the not-clustered recruit. Considerable variation in frequency distributions of PPD alterations was observed, therefore significant (p < 0.1) mean increase (1-sample t-test) and skew g1 (S-statistic) were additionally considered to define an "active" case. A total of 7 recruits (6.7%) met the criteria. Logistic regression analysis revealed a significant influence of self-reported smoking habits on activity status. Thus, heavy smokers (> 20 cigarettes/d) had a 14-fold higher risk (p = 0.030) for developing or progressing periodontitis compared to non- or light smokers (< 10 cigarettes/d). In particular, cluster B recruits appeared to have a lower risk (p = 0.11) for developing periodontitis than cluster C recruits (established periodontitis, high DMF-S). A. actinomycetemcomitans was isolated in 29 recruits (27.6%) at baseline and 30 recruits (28.6%) after 12 months. Presence of the organism was not a risk factor for periodontitis. However, in active subjects, significantly more samples were only A. actinomycetemcomitans-positive at re-examination compared to inactive recruits. It was concluded that smoking is a significant risk factor for periodontitis. Subjects with established periodontitis tend to deteriorate further. A. actinomycetemcomitans seems not to increase the risk for developing or progressing periodontitis in this age group. Longer studies involving larger populations are needed to confirm these observations.

Ultrasonic determination of gingival thickness. Subject variation and influence of tooth type and clinical features

The objectives of the present study were (I) to determine the validity and reliability of measuring gingival thickness (GTH) with a recently developed, commercially available ultrasonic device; (II) to measure GTH in relation to tooth type and age of proband; (III) to correlate GTH with varying forms of premolars, canines and incisors. Ultrasonic measurements were performed in 200 periodontally healthy, male probands representing 3 different age groups (20-25, 40-45, 55-60 years). In the maxilla, mean GTH varied between 0.9 mm (canines, 1st molars) and 1.3 mm (2nd molars). In the mandible respective mean values ranged between 0.8 mm (canines) and 1.5 mm (2nd molars). No differences in means and standard deviations (0.36-0.39 mm) were observed in different age groups. In order to correlate GTH with other clinical parameters and form of tooth, in 42 probands of the youngest age group, presenting with no attrition or abrasion, no artificial crown restorations and (following prophylaxis) no overt gingivitis and no periodontal probing depth in excess of 3 mm, detailed clinical measurements and stone model cast analyses were performed. By stepwise multiple linear regression analysis, 24% (p < 0.0001) of the variation of GTH was explained by probing depth, recession, width of gingiva and tooth type. The ratio of the width of the crown to its length was not included into the model. When performing analysis of covariance with the subject as factor, the model was improved, now explaining 41% of the variation of GTH. In this model, the influence of periodontal probing depth was decreased, and recession was not included. It was concluded that there are individual differences in GTH (i.e., different biotypes). However, thickness mainly depends on tooth type and is correlated with width of gingiva. There appears to be no association with shape and form of the tooth. Validity and reliability of measuring GTH with the ultrasonic device was found to be excellent.

Natural distribution of oral Actinobacillus actinomycetemcomitans in young men with minimal periodontal disease

A total of 1005 subgingival and extracrevicular samples from 201 male recruits, 18-25 yr old, were selectively cultivated for Actinobacillus actinomycetemcomitans. The organism was isolated in 55 subjects (27%); 9.5% of pooled subgingival plaque samples from first molars, 14% cheek mucosa, 20% dorsum of tongue and 20% saliva samples were culture-positive. In order to divide the study population into distinct clinical categories, cluster analysis was performed, based on previous caries experience, probing pocket depth categories, bleeding scores, visible plaque and calculus. Two clusters (n = 86 and n = 92, respectively) were identified with no or minimal periodontal disease (mean +/- standard deviation % of periodontal probing depth 1-2 mm 78.7 +/- 10.4% and 57.4 +/- 12.6%, respectively; virtually no periodontal probing/depth in excess of 4 mm) and a relatively low DMF-S (22 +/- 13). A third cluster (n = 22) had, in contrast, a high DMF-S (47.7 +/- 17.2) and a relatively high % of periodontal pockets of > or = 5 mm (5.9 +/- 5.2%). Prevalence of A. actinomycetemcomitans in this cluster was 41%, while the organism was found in 23% and 27% in the minimally diseased populations (p < 0.15). Whereas no heterogeneity of associations between subgingival and extracrevicular occurrence of the organism could be ascertained in different clusters, the organism was significantly more often identified in extracrevicular material, especially dorsum of tongue samples, compared with subgingival plaque (McNemar's chi2 = 12.45, p < 0.001). Multiple linear regression analysis revealed the number of A. actinomycetemcomitans positive samples as well as the % of sites bleeding on probing being positively associated with the % of sites with a probing pocket depth of > or = 5 mm (R2 = 0.345, p < 0.0001). The present large-scale investigation points to the wide distribution of this putative periodontopathogen in young individuals with minimal periodontal disease.

Potential diagnostic value of sampling oral mucosal surfaces for Actinobacillus actinomycetemcomitans in young adults

Actinobacillus actinomycetemcomitans has been implicated in the pathogenesis of several forms of early onset and refractory adult periodontitis. Early diagnosis of colonization of the oral cavity might be of importance in order to initiate preventive measures. The aim of the present study was to determine the potential diagnostic value of oral mucosal and salivary tests to identify, among healthy young men with no or minor periodontal disease, individuals colonized by A. actinomycetemcomitans. Two hundred and one male recruits, 18-25 yr of age, took part in the present study. Mean values of periodontal parameters suggested only minor periodontal disease. Of the sites, 64.8 +/- 17.6% (mean +/- SD) had a periodontal probing depth (PPD) of 1 or 2 mm, only 1.6 +/- 2.9% deep sites of > or = 5 mm were detected. More than 1000 subgingival and extracrevicular samples were selectively cultivated for A. actinomycetemcomitans. The organism was isolated in 55 subjects (27%). The odds for presence of at least 1 deep site of 5 mm was increased by a factor 1.99 if A. actinomycetemcomitans, could be recovered. In identifying subjects colonized by A. actinomycetemcomitans, diagnostic test parameters sensitivity and predictive value for a negative test were 74.5 +/- 5.9% and 91.1 +/- 2.3%, respectively, for both saliva and dorsum of tongue samples. In contrast, pooled subgingival plaque from mesial surfaces of 1st molars was only 34.5 +/- 6.4% sensitive; the negative predictive value was 80.2 +/- 3.0%. The results point to a high diagnostic value of oral mucosal and especially saliva samples to identify young adult individuals colonized by A. actinomycetemcomitans.

Management of furcation-involved teeth. A retrospective analysis

In the present study, data from more than 550 periodontally diseased patients with more than 1100 furcation invasions were retrospectively analysed. There were apparent differences in the distribution of different furcation degrees in patient populations treated by 2 differently experienced operators. However, treatment modality patterns were rather similar. Scaling during periodontal flap surgery was the most often performed treatment procedure in degree I (97-98%) and II (75-83%) involvements. About 44% of degree III involved teeth were extracted. In order to determine the influence of degree of furcation involvement, tooth type and operator variability on treatment modality, logistic regression analysis was applied. Degree of furcation involvement was an important indicator variable in all models. Scaling as a sole measure was mainly performed in relation to degree I of furcation involvement. With every increase in degree, the odds of scaling decreased by factor 12.7. The odds of root resection was upper 1st molars 46 x higher than in wisdom teeth or lower 2nd molars with the same degree of involvement, but only 3.3 x higher than in lower 1st molars. Tunnel preparation as well as regenerative procedures were mainly confirmed to lower molars. Operator variability was only introduced as a covariate in the extraction model. hence, despite of different operator skill and severity of periodontal disease in treated populations, decision for one or the other treatment modality seems to depend essentially on degree of furcation involvement as well as tooth type.

Use of various genetic markers in differentiation of Mycobacterium bovis strains from animals and humans and for studying epidemiology of bovine tuberculosis

One hundred fifty-three Mycobacterium bovis strains from cattle, various animal species from zoos and wild parks, and humans were analyzed for three different genetic markers for use in the epidemiology of bovine tuberculosis. M. bovis strains isolated from cattle were found to carry a single IS6110 element, whereas the majority of strains from other animals such as antelopes, monkeys, and seals harbored multiple IS6110 elements, suggesting that the reservoirs in cattle and wild animals are separated. Because the single IS6110 element in cattle strains is located at the same chromosomal position, strain differentiation by insertion sequence fingerprinting was hampered. Therefore, we investigated the usefulness of the direct repeat and polymorphic GC-rich repeat elements for strain differentiation. Both markers allowed sufficient strain discrimination for epidemiological purposes. Evidence is presented that in Argentina, most human M. bovis infections are due to transmission from cattle, whereas M. bovis infections among humans in the Netherlands are mainly contracted from animals other than cattle. Various outbreaks of M. bovis among animals and humans are described, including a small one which likely involved transmission from human to human.