Biomedical subjects

J C Gunsolley

Publications and source records attributed to J C Gunsolley.

At least 19 recordsLinked to original sources

PubMed2001

Is loss of attachment due to root planning and scaling in sites with minimal probing depths a statistical or real occurrence?

BACKGROUND: Following root planing and scaling many studies have implied an association between a loss of clinical attachment at sites with initially shallow pockets (1 to 3 mm) and gains in attachment level for deeper probing depths. However, these effects are also consistent with a statistical phenomenon referred to as regression towards the mean. This principle suggests that extreme values will moderate the next time they are recorded. The purpose of this report was to estimate the effect that regression towards the mean has on perceived changes in attachment level after root planing and scaling. METHODS: During the initial examination, 2 different investigators conducted 2 full-mouth probings. Two quadrants were randomly selected to be root planed and scaled until the root surfaces were smooth by tactile touch of an explorer. The 2 remaining quadrants were not treated. At 4 to 6 weeks after treatment, another full mouth probing was done. An examiner who was blind to the quadrants that had been scaled measured attachment level and probing depth after therapy. This study design provided periodontal measurements before and after root planing and scaling, measurements before and after a period of 4 to 6 weeks of no therapy, and duplicate measurements at the beginning of the study. RESULTS: Using the repeat examination when no true change could occur, shallow sites (< or =3 mm of probing depth) showed average negative differences between repeat attachment level measurements (-0.23 mm), which mimicked loss of periodontal attachment. Deep sites, (>6 mm) showed average positive values (0.40) mimicking gain in attachment level. These results suggest that regression towards the mean is a significant effect in this data set. Both shallow non-scaled and scaled sites had similar differences in repeat measures (-0.28 mm, -0.25 mm) which were also similar to and not statistically different from changes after therapy for both non-scaled (-0.21 mm) and scaled sites (-0.08 mm). Thus not only does this data set exhibit regression towards the mean, but it explains the majority of perceived loss of periodontal attachment after scaling at sites that have minimal probing depth. CONCLUSIONS: These results suggest that the majority of perceived loss of attachment due to scaling at sites of minimal probing depth that have been reported in many studies may be due a statistical phenomenon called regression towards the mean.

Dental Scaling↗

PubMed2000

Treatment of human mucogingival defects utilizing a bioabsorbable membrane with and without a demineralized freeze-dried bone allograft.

BACKGROUND: The use of guided tissue regeneration (GTR) has become an effective procedure for the treatment of gingival recession. No reports exist on the use of a bioabsorbable membrane in combination with a demineralized freeze-dried bone allograft (DFDBA) for the treatment of these defects. METHODS: Fourteen (14) patients with 17 recession defects were included in this clinical study. Each patient had at least 1 tooth with 3 mm or greater marginal tissue recession on the facial surface as measured from the cemento-enamel junction (CEJ). Each patient was treated by GTR using a bioabsorbable membrane. When the first patient presented for inclusion in the study, a coin was flipped to determine if the tooth being treated would be a test tooth (DFDBA) or a control tooth (no DFDBA). Each subsequent patient was alternated between test and control. Immediately prior to the surgical procedure, measurements were made which included recession depth, recession width at the widest point, probing depth, amount of keratinized tissue, and marginal tissue thickness. Local anesthesia was administered, and a measurement from the CEJ to the bone crest was made by sounding through the attachment. RESULTS: The mean initial recession for all defects was 3.35 mm (SD +/- 0.49) and at 6 months postsurgery, mean recession was 0.47 mm (SD +/0.62). This correlated to 86% root coverage for both treatments. For all defects treated, there was a statistically significant increase in keratinized tissue (mean 0.88 mm) and tissue thickness (mean 0.47 mm) and a significant decrease in probing bone level (mean 0.76 mm). No statistically significant differences were observed between groups for any parameter. CONCLUSIONS: Although only 14 subjects with 17 defects were included in this study, the results suggest that the treatment of human gingival recession with a bioabsorbable membrane with or without the use of DFDBA results in significant root coverage, and slight, but significant improvements in keratinized tissue, tissue thickness, and bone level. The greatest limitation of the study was its lack of statistical power. Twenty-two (22) subjects would have been required for the results of the study to show equivalence between groups.

Absorbable Implants↗

PubMed2000

Evidence of a substantial genetic basis for risk of adult periodontitis.

BACKGROUND: A few previous studies have suggested that risk for adult periodontitis (AP) has a genetic (heritable) component. We estimated genetic and environmental variances and heritability for gingivitis and adult periodontitis using data from twins reared together. METHODS: One hundred seventeen (117) pairs of adult twins (64 monozygotic [MZ] and 53 dizygotic [DZ] pairs) were recruited. Probing depth (PD), attachment loss (AL), plaque, and gingivitis (GI) were assessed on all teeth by two examiners. Measurements were averaged over all sites, teeth, and examiners. Extent of disease in subjects was defined at four thresholds: the percentage of teeth with AL > or = 2, AL > or = 3, PD > or = 4, or PD > or = 5 mm. Genetic and environmental variances and heritability were estimated using path models with maximum likelihood estimation techniques. RESULTS: MZ twins were more similar than DZ twins for all clinical measures. Statistically significant genetic variance was found for both the severity and extent of disease. AP was estimated to have approximately 50% heritability, which was unaltered following adjustments for behavioral variables including smoking. In contrast, while MZ twins were also more similar than DZ twins for gingivitis scores, there was no evidence of heritability for gingivitis after behavioral covariates such as utilization of dental care and smoking were incorporated into the analyses. CONCLUSIONS: These results confirm previous studies and indicate that approximately half of the variance in disease in the population is attributed to genetic variance. The basis for the heritability of periodontitis appears to be biological and not behavioral in nature.

Adult↗

PubMed1999

Antiphosphorylcholine antibody levels are elevated in humans with periodontal diseases.

Human immunoglobulin G2 (IgG2) serum concentrations and the IgG2 antibody response to Actinobacillus actinomycetemcomitans can be influenced by genes, by environmental factors such as smoking, and by periodontal disease status. Examination of the IgG2 response to phosphorylcholine (PC), a response thought to be mainly induced by the C polysaccharide of Streptococcus pneumoniae, suggested that periodontal disease status was also associated with this response. This prompted the hypothesis that PC is an important oral antigen associated with organisms in the periodontal flora and that anti-PC antibody is elevated as a consequence of periodontal disease. Subjects in various periodontal disease diagnostic categories in which attachment loss is exhibited were tested for anti-PC in serum. Those with adult periodontitis, localized juvenile periodontitis, generalized early-onset periodontitis, and gingival recession all had similar levels of anti-PC IgG2 serum antibody which were significantly greater than in the group of subjects with no attachment loss. Analysis of plaque samples from subgingival and supragingival sites in all diseases categories for reactivity with the anti-PC specific monoclonal antibody TEPC-15 revealed that a substantial proportion of the bacteria in dental plaque (30 to 40%) bear PC antigen; this antigen was not restricted to morphotypes resembling only cocci but was also present on rods and branched filamentous organisms. We found that S. mitis, S. oralis, and S. sanguis, as well as oral actinomycetes, including A. viscosus, A. odontolyticus, and A. israelii, incorporated substantial amounts of [(3)H]choline from culture media. Further analysis of antigens derived from these organisms by Western blot indicated that S. oralis, S. sanguis, A. viscosus, A. odontolyticus, and A. israelii contained TEPC-15-reactive antigens. The data show that many commonly occurring bacterial species found in dental plaque contain PC antigen and that immunization with plaque-derived PC antigens as a consequence of inflammation and periodontal attachment loss may influence systemic anti-PC antibody concentrations.

Actinomycetales↗

PubMed1999

Antibody reactive with Porphyromonas gingivalis serotypes K1-6 in adult and generalized early-onset periodontitis.

BACKGROUND: Six serotypes of Porphyromonas gingivalis have recently been described. We sought to test the hypothesis that serotype specific carbohydrates from these strains are important antigens that elicit potent immune responses. METHODS: Serum concentrations of IgG reactive with P. gingivalis serotypes K1-K6 were determined for 28 adult (AP) and 28 generalized early-onset (G-EOP) periodontitis patients previously determined to be seropositive for a broken cell preparation of P. gingivalis. To confirm relationships suggested for K1, K2, and K6 in the analysis of initial data, the study population was increased to 133. RESULTS: Frequency of seropositivity for the 6 serotypes ranged from 26 to 54% of subjects. IgG concentrations ranged from 0 to 453 microg/ml with many subjects seropositive to more than one serotype. Concentrations for the subset of patients who was seropositive were high (mean responses ranged from 20 to 105 microg/ml for the 6 serotypes). Significant correlations between seropositivity to serotypes K1 and K5 as well as between K5 and K6 were found. CONCLUSIONS: We examined the relationship of diagnosis, race, gender, smoking, probing depth, attachment loss, and antibody reaction with the P. gingivalis serotypes by analysis of variance. Initial findings suggested potential relationships between diagnosis, smoking, race, gender, and antibody reactive with serotypes K1, K2, and K6. A significant relationship did exist between smoking and decreased antibody reactive with P. gingivalis serotype K2. No other relationships were substantiated. We also examined the IgG subclass distribution and found that responses were almost exclusively IgG2. These data support the concept that antibody responses to all 6 serotypes are common in both AP and G-EOP and that these K serotype carbohydrates elicit potent IgG2 responses.

Adult↗

PubMed1998

Comparison of debris extruded apically in straight canals: conventional filing versus profile .04 Taper series 29.

The purposes of this study were to determine quantitatively the amount of debris and irrigant forced in an apical direction, the frequency of apical plug development, and the time required to prepare canals when a step-back technique using K-files was compared with the .04 Taper system. Sixty-nine extracted teeth with straight canals were divided into four statistically similar groups. Two groups were instrumented either 1 mm short of the apical foramen or to the apical foramen with K-files. The other two groups were instrumented to the same levels using .04 Taper files. The extruded debris and irrigant were collected in preweighed vials. The weight of the debris and volume of irrigant extruded using both techniques were compared and analyzed using paired t test and one-way ANOVA. Tukey's Multiple Comparisons Procedure showed K-files used to the apical foramen extruded significantly more debris than the other three groups (p < 0.01). The .04 Taper files used 1 mm short extruded less debris than the other groups. Significantly more irrigant was extruded when filing was performed to the apical foramen (p < 0.007), regardless of the technique used. More apical plugs were created in teeth filed short of the apical foramen, but the difference between the two preparation techniques was not statistically significant. It took significantly less time to instrument canals with the .04 Taper system than with K-files (p < 0.002).

Analysis of Variance↗

PubMed1998

The effect of clinical information on the histopathologic diagnosis of oral epithelial dysplasia.

OBJECTIVES: The purpose of this study was to test the hypothesis that clinical information submitted with biopsy specimens helps pathologists be more consistent and accurate in diagnosing oral epithelial dysplasia. STUDY DESIGN: Each of six board-certified oral and maxillofacial pathologists examined the same set of 120 oral biopsies (involving diagnoses ranging from hyperkeratosis to severe epithelial dysplasia); they had examined these same biopsies in a previous study, but this time the clinical information was provided for each case. The examiner's diagnosis was compared to the sign-out diagnosis for each case. RESULTS: Rates of exact agreement with the sign-out diagnosis averaged 38.5%, and there was 85.4% agreement within one histologic grade. The rate of agreement in distinguishing epithelial dysplasia from no dysplasia was 71.4%. These results, when compared to those from a previous study in which the same examiners had evaluated the same slides but without clinical histories, represent a 2.5% to 20% decrease for exact agreement among the six pathologists, a 0% to 8.5% decrease for agreement within one histologic grade, and a 0% to 23.4% decrease for agreement regarding the presence or absence of epithelial dysplasia. CONCLUSIONS: When clinical information was used, accuracy and consistency among board-certified oral and maxillofacial pathologists in the diagnosis of oral epithelial dysplasia was not improved. In fact, there was a decrease in accuracy.

Biopsy↗

PubMed1998

The effect of smoking on individuals with minimal periodontal destruction.

Recent studies have demonstrated that smoking is associated with periodontal destruction. The majority of these studies have focused on periodontal disease groups with moderate or severe periodontal destruction. Additionally, there have been few reports investigating the relationship between smoking and gingival recession. The goal of this report was to investigate the effect of smoking on periodontal destruction and recession in subjects with minimal or no interproximal attachment loss. This is a cross-sectional study of 142 non-smoking subjects and 51 smoking subjects. Subjects could have no more than one tooth with a site of interproximal attachment loss > or =2 mm. Subjects could, however, have attachment loss associated with recession. For three different methods of summarizing attachment loss measurements at a subject level, including average attachment loss, percentage of teeth with one site of 2 mm of attachment loss, and the percentage of teeth with one site of 5 mm of attachment loss, smoking subjects had approximately twice as much attachment loss than their non-smoking counterparts. Smoking subjects also had significantly greater recession (P < 0.05) [0.056+/-0.017 mm] than non-smoking subjects (0.025+/-0.005 mm). Recession sites occurred primarily on the facial surface of maxillary molars and bicuspids and mandibular central incisors and bicuspids. The results suggest a strong association between smoking and both attachment loss and recession in subjects who have minimal or no periodontal disease.

Adolescent↗

PubMed1998

The influence of smoking and race on adult periodontitis and serum IgG2 levels.

Smoking is a known risk factor for developing periodontal diseases, but the risk appears to be greater for white smokers than black smokers. Furthermore, it has been reported that young white subjects have significantly lower levels of serum IgG2 than their non-smoking counterparts while young black adult subjects are generally not affected by smoking. These relationships prompted the hypothesis that adult white subjects, including periodontitis subjects, who smoked would have more attachment loss than adult black subjects and that smoking would be associated with lower serum IgG2 levels in adult white subjects but not in adult black subjects. Smoking status was established from serum cotinine levels determined by radioimmunoassay. Serum IgG subclass levels were determined using radial immunodiffusion. White adult periodontitis (AP) and non-periodontitis (NP) subjects who smoked had greater mean attachment loss per site than their non-smoking counterparts. Furthermore, smoking white AP subjects and their age-matched NP controls had substantially less IgG2 in their serum. In marked contrast, we were unable to detect any increase in periodontal destruction or a significant decrease in serum IgG2 levels in smoking black AP subjects or their age-matched controls. However, IgG1 and IgG4 levels were reduced in smoking black AP subjects. IgG3 was the only subclass in adults that was unaffected by smoking. IgG2 can be a good opsonin and may help control periodontitis-associated bacteria in adults. Even though a cause-and-effect relationship has not been established, the association between a smoking-related decrease in serum IgG2 and an increase in periodontal destruction in white subjects is striking.

Adult↗

PubMed1998

Equivalence and superiority testing in regeneration clinical trials.

The purpose of this report is to investigate sample size requirements for both equivalence and superiority studies investigating products used in regeneration. The goal of a superiority clinical trial is to determine if a new therapy is superior to an established therapy or placebo. In contrast to superiority trials, equivalence trials are used to determine if a new product has similar therapeutic properties to an established product. The sample sizes for the two different types of clinical trials were based on the following assumptions: an alpha of 0.05, a power of 0.80, a 2 group parallel arm study, and equal variances and sample sizes for both groups. Separate sample size calculations were done for both intrabony defects and Class II furcation defects. Sample sizes for the equivalence and superiority trials using the same criteria were the same. However, criteria for estimating sample sizes for equivalence clinical trials require much smaller differences between groups, resulting in much larger sample sizes. A criterion of a 20% difference between groups of the total therapeutic effect resulted in sample sizes which ranged from 64 to 127 in equivalence clinical trials. These samples sizes are much larger than have been generally used in clinical trials investigating periodontal regeneration.

Alveolar Bone Loss↗

PubMed1998

Adjunctive use of a subgingival controlled-release chlorhexidine chip reduces probing depth and improves attachment level compared with scaling and root planing alone.

The present studies evaluated the efficacy of a controlled-release biodegradable chlorhexidine (CHX) (2.5 mg) chip when used as an adjunct to scaling and root planing on reducing probing depth (PD) and improving clinical attachment level (CAL) in adult periodontitis. Two double-blind, randomized, placebo-controlled multi-center clinical trials (5 centers each) were conducted; pooled data are reported from all 10 centers (447 patients). At baseline, following 1 hour of scaling and root planing (SRP) in patients free of supragingival calculus, the chip was placed in target sites with PD 5 to 8 mm which bled on probing. Chip placement was repeated at 3 and/or 6 months if PD remained > or = 5 mm. Study sites in active chip subjects received either CHX chip plus SRP or SRP alone (to maintain study blind). Sites in placebo chip subjects received either placebo chip plus SRP or SRP alone. Examinations were performed at baseline; 7 days; 6 weeks; and 3, 6, and 9 months. At 9 months significant reductions from baseline favoring the chlorhexidine chip compared with both control treatments were observed with respect to PD (chlorhexidine chip plus SRP, 0.95 +/- 0.05 mm; SRP alone, 0.65 +/- 0.05 mm, P < 0.001; placebo chip plus SRP, 0.69 +/- 0.05 mm, P < 0.001) and CAL (chlorhexidine chip plus SRP, 0.75 +/- 0.06 mm; SRP alone, 0.58 +/- 0.06 mm, P < 0.05; placebo chip plus SRP, 0.55 +/- 0.06 mm, P < 0.05). The proportion of patients who evidenced a PD reduction from baseline of 2 mm or more at 9 months was significantly greater in the chlorhexidine chip group (19%) compared with SRP controls (8%) (P < 0.05). Adverse effects were minor and transient toothache, including pain, tenderness, aching, throbbing, soreness, discomfort, or sensitivity was the only adverse effect that was higher in the chlorhexidine group as compared to placebo (P = 0.042). These data demonstrate that the adjunctive use of the chlorhexidine chip results in a significant reduction of PD when compared with both SRP alone or the adjunctive use of a placebo chip. These multi-center randomized control trials suggest that the chlorhexidine chip is a safe and effective adjunctive chemotherapy for the treatment of adult periodontitis.

Adult↗

PubMed1998

A longitudinal comparison of tooth whitening resulting from dentifrice use.

The effect of twice-daily brushing with one of three different dentifrices (Arm & Hammer Dental Care, Arm & Hammer Dental Care Extra Whitening, Crest) on stain removal and tooth whitening was examined in 115 volunteers over a period of 12 weeks. The facial surfaces of 12 anterior teeth were assessed for stain using a published, modified version of a standard stain index. Whiteness was measured on teeth 8 and 9 using a single Vita Lumin-Vaccum Shade Guide for consistency. At baseline, the mean facial stain scores were significantly higher (p < 0.05-0.01) for both Arm & Hammer dentifrices than for Crest. In addition, the tooth shades, as indicated by the stain guide, specifically the b* values representing yellowness, were quantified using a Minolta spectrophotometer. Arm & Hammer Dental Care Extra Whitening formula was found to be significantly better than Crest at removing naturally occurring extrinsic stain. The difference between Arm & Hammer Dental Care Extra Whitening and Crest became significant (p < 0.01) after two weeks of use, and remained intact during the balance of the study, achieving p values of 0.0002 for at least one of the three assessed parameters (total stain, proximal, and facial) at weeks 4 and 12. The study also found that Arm & Hammer Dental Care produced a significant increase in tooth whiteness by week 12, whereas Crest showed no such increase at any time during the study. These results suggest that the two Arm & Hammer Baking Soda products are more effective in reducing stain and increasing whiteness than the standard silica-based dentifrice. Their effectiveness is not related to abrasivity since they are less abrasive to tooth enamel than the silica-based product tested.

Adolescent↗

PubMed1997

Antibody reactive with Actinobacillus actinomycetemcomitans leukotoxin in early-onset periodontitis patients.

The objective of this study was to determine whether a relationship exists between antibody reactive with the Actinobacillus actinomycetemcomitans leukotoxin and the severity of periodontal disease. Serum concentrations of antibody reactive with the leukotoxin were determined for 119 early-onset periodontitis patients and 59 non-periodontitis subjects using limiting dilution analysis on Western blots. Immunoglobulin G (IgG) antibody reactive with the A. actinomycetemcomitans leukotoxin ranged from undetectable to 29 micrograms/ml (mean = 3.13 +/- 0.97 micrograms/ml for the generalized early-onset periodontitis and 2.17 +/- 0.86 micrograms/ml for the localized juvenile periodontitis patients vs 0.32 +/- 0.24 ng/ml for 59 non-periodontitis controls), and the dominant subclass was IgG1. Analysis of the relationship between antibody reactive with A. actinomycetemcomitans sonicate, A. actinomycetemcomitans leukotoxin and attachment loss patterns indicates that seropositive generalized early-onset periodontitis patients had decreased attachment loss compared with patients lacking this antibody. The statistical relationship appeared to be stronger for the sonicate than the purified leukotoxin. These data suggest that antibody reactive with A. actinomycetemcomitans leukotoxin may be protective in early-onset periodontitis, but given that the sonicate appeared better than the leukotoxin alone, it is not likely that leukotoxin is the only antigen of importance to host defense.

Adolescent↗

PubMed1997

The effect of race, smoking and immunoglobulin allotypes on IgG subclass concentrations.

In previous studies we have demonstrated that serum IgG subclass concentrations are influenced by both race and periodontal disease diagnosis. Furthermore, we have shown that smoking habits modify the concentrations of some IgG subclasses in specific racial and diagnostic groups. In view of a large amount of data showing strong associations between immunoglobulin allotypes and IgG subclass concentrations we have investigated the effects of race, smoking and IgG allotype on IgG subclass concentration in a population of subjects with or without various forms of periodontitis. The results indicated that there are complex relationships between these factors in their effects on individual IgG subclass levels, and that effects unique to black or white subject groups, or to specific periodontal diagnostic groups and racial subgroups, were evident. In blacks with chronic adult periodontitis IgG1 was lower in smokers, while in generalized early-onset periodontitis patients IgG2 was lower in smokers. IgG4 was independently affected by gender (males higher), smoking (smokers lower) and GM23 (GM23 positive subjects higher), in black subjects only. In white subjects, complex relationships between smoking and allotypic markers were noted but no influence of periodontal diagnosis was found. White GM23 negative subjects who smoked had lower levels of IgG1 than GM23 positive subjects. White GM2 negative subjects who smoked had lower levels of IgG2, than did those who did not smoke. In contrast, smoking had no effect on IgG2 levels in GM2 positive subjects. Thus, in addition to immunoglobulin allotype, smoking is associated with IgG subclass concentrations; furthermore, in black subjects, periodontal diagnosis, gender and smoking all influence IgG subclass concentrations. These results demonstrate that genetic and environmental factors can interact to influence levels of individual subclasses.

Adult↗

PubMed1997

Effects of guided bone regeneration around commercially pure titanium and hydroxyapatite-coated dental implants. II. Histologic analysis.

The purpose of this study was to determine which treatment of a large osseous defect adjacent to an endosseous dental implant would produce the greatest regeneration of bone and degree of osseointegration: barrier membrane therapy plus demineralized freeze-dried bone allograft (DFDBA), membrane therapy alone, or no treatment. The current study histologically assessed changes in bone within the healed peri-implant osseous defect. In a split-mouth design, 6 implants were placed in edentulous mandibular ridges of 10 mongrel dogs after preparation of 6 cylindrical mid-crestal defects, 5 mm in depth, and 9.525 mm in diameter. An implant site was then prepared in the center of each defect to a depth of 5 mm beyond the apical extent of the defect. One mandibular quadrant received three commercially pure titanium (Ti) screw implants (3.75 x 10 mm), while the contralateral side received three hydroxyapatite (HA) coated root-form implants (3.3 x 10 mm). Consequently, the coronal 5 mm of each implant was surrounded by a circumferential defect approximately 3 mm wide and 5 mm deep. The three dental implants in each quadrant received either DFDBA (canine source) and an expanded polytetrafluoroethylene membrane (ePTFE), ePTFE membrane alone, or no treatment which served as the control. Clinically, the greatest increase in ridge height and width was seen with DFDBA/ePTFE. Histologically, statistically significant differences in defect osseointegration were seen between treatment groups (P < 0.0001: DFDBA/ePTFE > ePTFE alone > control). HA-coated implants had significantly greater osseointegration within the defect than Ti implants (P < 0.0001). Average trabeculation of newly formed bone in the defect after healing was significantly greater for HA-coated implants than for titanium (P < 0.0001), while the effect on trabeculation between treatments was not significantly different (P = 0.14). Finally, there were significantly less residual allograft particles in defect areas adjacent to HA-coated implants than Ti implants (P = 0.0355). The use of HA-coated implants in large size defects with DFDBA and ePTFE membranes produced significantly more osseointegration histologically than other treatment options and more than Ti implants with the same treatment combinations. The results of this study indicate that, although the implants appeared osseointegrated clinically after 4 months of healing, histologic data suggest that selection of both the implant type and the treatment modality is important in obtaining optimum osseointegration in large size defects.

Alveolar Bone Loss↗

PubMed1997

Effects of guided bone regeneration around commercially pure titanium and hydroxyapatite-coated dental implants. I. Radiographic analysis.

The purpose of this study was to determine which treatment of a large osseous defect adjacent to an endosseous dental implant would produce the greatest regeneration of bone and degree of osseointegration: barrier membrane therapy plus demineralized freeze-dried bone allograft (DFDBA), membrane therapy alone, or no treatment. The current study assessed radiographic density changes in bone within the healed peri-implant osseous defect. In a split-mouth design, 6 implants were placed in edentulous mandibular ridges of 10 mongrel dogs after preparation of 6 cylindrical mid-crestal defects, 5 mm in depth and 9.525 mm in diameter. An implant site was then prepared in the center of each defect to a depth of 5 mm beyond the apical extent of the defect. One mandibular quadrant received three commercially pure titanium (Ti) screw implants (3.75 X 10 mm), while the contralateral side received three hydroxyapatite (HA) coated root-form implants (3.3 X 10 mm). Consequently, the coronal 5 mm of each implant was surrounded by a circumferential defect approximately 3 mm wide and 5 mm deep. The three dental implants in each quadrant received either DFDBA (canine source) and an expanded polytetrafluoroethylene membrane (ePTFE), ePTFE membrane alone, or no treatment (control). Standardized radiographs were taken at 1 week and 4 months post-implant placement. Computer-assisted densitometric image analysis (CADIA) was performed at 6 areas of interest (coronal, middle, and apical defect areas mesial and distal to each implant) for each of the implant sites. Significantly greater increase in bone density was obtained using DFDBA/ePTFE compared to ePTFE alone or the controls; likewise, ePTFE alone resulted in greater bone density change than the controls. There were no significant differences in radiographic bone density adjacent to Ti versus HA-coated implants. When 3 dogs having postoperative membrane complications were eliminated from the analysis, the results were similar with the exception that defects adjacent to Ti implants had significantly less density gain when compared to HA-coated implants. The results of this study indicate the use of DFDBA/ePTFE in large surgically-created defects promotes a denser healing of bone adjacent to implants when measured radiographically than either ePTFE alone or no treatment.

Absorptiometry, Photon↗

PubMed1997

A comparison of IgG antibody reactive with Bacteroides forsythus and Porphyromonas gingivalis in adult and early-onset periodontitis.

Recent work has indicated that Bacteroides forsythus and Porphyromonas gingivalis are significant local risk factors for periodontitis. Several reports find that both organisms are frequently associated with periodontitis lesions and often are present together. We have previously shown that early-onset periodontitis patients seropositive for P. gingivalis have less attachment loss than seronegative patients. In this study, we determined serum IgG antibody concentrations reactive with B. forsythus in adult and early-onset periodontitis patients using an ELISA and used P. gingivalis in the same populations as a positive control. The results for P. gingivalis were consistent with previous work and indicated that 47%, 36%, and 33% of adult, generalized early-onset, and localized juvenile patients were seropositive, respectively. Mean serum IgG concentrations for the three groups were 5.36 microg/ml, 5.65 microg/ml, and 5.44 microg/ml for adult, generalized early-onset, and localized juvenile patients, respectively. In contrast, for B. forsythus only 11%, 14%, and 10% of adult, generalized early-onset, and localized juvenile patients were seropositive, with mean serum IgG concentrations of 0.46 microg/ml, 0.46 microg/ml, and 0.47 microg/ml, respectively. This suggests that B. forsythus is either poorly immunogenic or less invasive than P. gingivalis. If most patients fail to mount an immune response to B. forsythus and it is invasive, it may explain why this organism is a risk factor for disease.

Adult↗

PubMed1997

The effect of smoking on serum IgG2 reactive with Actinobacillus actinomycetemcomitans in early-onset periodontitis patients.

High titers of serum IgG2 reactive with Actinobacillus actinomycetemcomitans are present in early-onset periodontitis (EOP) patients and it appears that anti-A. actinomycetemcomitans may be protective. Smoking is associated with increased periodontal disease severity in generalized early-onset periodontitis (G-EOP) patients, but is not associated with periodontal disease severity in patients with localized juvenile periodontitis (LJP). Furthermore, smoking is associated with reduced serum IgG2 levels in black patients with G-EOP but not in those with LJP. Based on this selective effect of smoking, we hypothesized that smoking would be associated with a reduction of specific IgG2 reactive with A. actinomycetemcomitans in black G-EOP patients but not black LJP patients. In addition, we examined IgG2 responses to carbohydrate antigens from non-periodontal pathogens including Haemophilus influenzae b oligosaccharide antigen (Hib) and the Streptococcus pneumoniae antigen phosphocholine (PC). Smoking status was assessed from serum cotinine levels, and IgG2 specific for A. actinomycetemcomitans, Hib, and PC was assessed by ELISA. Our study revealed that smoking was correlated with a dramatic reduction in serum IgG2 anti-A. actinomycetemcomitans in G-EOP smokers but not in LJP smokers. In contrast, anti-Hib IgG2 and anti-PC IgG2 were not affected in either G-EOP or LJP patients. In short, these results indicate that smoking is associated with a reduction in serum IgG2 anti-A. actinomycetemcomitans in black G-EOP subjects, but IgG2 reactive with other antigens may not be reduced in G-EOP smokers.

Adolescent↗