Effects of plaque,psychological stress and gender on crevicular Il-1beta and Il-1ra secretion

OBJECTIVES: The study aimed to analyse (a) whether the effects of psychological stress and of experimental gingivitis on interleukin-1beta (Il-1beta) described before are compensated by concomitant increases in Il-1 receptor antagonist (Il-1ra), and (b) whether there do exist any gender differences in the Il-1 responses to experimental gingivitis and to psychological stress. MATERIALS AND METHODS: Thirteen medical students participating in a major academic exam (seven males, six females) and 14 medical students without academic stress (eight males, six females) refrained from oral hygiene in two antagonistic quadrants for 28 days (plaque) while they maintained oral hygiene in the remaining quadrants (hygiene). Weekly crevicular fluid samples of plaque and hygiene sites were assayed for Il-1beta and Il-1ra. RESULTS: Neither stress nor experimental gingivitis exerted significant effects on Il-1ra. In controls, we observed significant gender and gender x time effects on Il-1beta; comparing stress groups, gender x time and stress x gender x time interactions became significant. Women show a reduced Il-1beta response to plaque at rest and an increased response under stress. Similar results were found with respect to bleeding on probing. CONCLUSIONS: Gender must be controlled in studies on periodontal responses to pathogens. Stress plays a role in these responses.     

Increase of crevicular interleukin 1b under academic stress at experimental gingivitis sites and at sites of perfect oral hygiene

Abstract . This study analyses the effects of academic stress on crevicular interleukin-1b (Il-1β) both at experimental gingivitis sites and at sites of perfect oral hygiene. Il-1β is thought to play a predominant role in periodontal tissue destruction. 13 medical students participating in a major medical exam (exam group) and 13 medical students not participating in any exam throughout the study period (control group) volunteered for the study. In a split-mouth-design, they refrained from any oral hygiene procedures in two opposite quadrants for 21 days (experimental gingivitis) while they maintained perfect hygiene levels at the remaining sites. Crevicular fluid was sampled for further Il-1b analysis at teeth 5 and 6 of the upper jaw at days 1, 5, 8, 11, 14, 18 and 21 of the experimental gingivitis period. Exam students showed significantly higher Il-1b levels than controls both at experimental gingivitis sites (area under the curve, exam group: 1240.64±140.07; control group: 697.61±111.30; p =0.004) and at sites of perfect oral hygiene (exam group: 290.42±63.19; control group: 143.98±42.71; p =0.04). These results indicate that stress might affect periodontal health by increasing local Il-1β levels especially when oral hygiene is neglected.     

Crevicular fluid levels of interleukin-1alpha and interleukin-1beta during experimental gingivitis in young and old adults

The purpose of the present investigation was to study the effect of age on interleukin-1alpha (Il-1alpha) and interleukin-1beta (Il-1beta) production during experimental gingivitis. One group of five young subjects (20-22 years old) and another group of five older subjects aged 61-65 years were involved in the study. A professional plaque control programme was undertaken to establish healthy gingival conditions at baseline. The examination included the mesiobuccal sites of the Ramfjord teeth (16, 21, 24, 36, 41, 44). Clinical measurements and gingival crevicular fluid (GCF) samples were obtained at baseline, at 21 days of no oral hygiene and one week later after professional cleaning and re-establishment of oral hygiene procedures. Results showed significant differences between the two groups with regard to the amount of plaque accumulation clinical signs of gingival inflammation and GCF volume all of which proved to be more pronounced in the older group. The laboratory data presented a remarkable increase of Il-1alpha levels at day 21 for both groups which were significantly reduced at day 28. For the older adults group the Il-1beta values increased significantly at day 21 and recovered at day 28. For the young adults group these values, despite a small statistically insignificant progressive increase at day 21, remained at low levels during the experimental process. This was the only difference in the cytokines values between older and young adults. It was concluded that low Il-1beta levels observed in the young adults group might explain the less pronounced clinical signs observed during the development of gingivitis in the younger subjects.     

Effects of experimental gingivitis on crevicular PGE2 in a split mouth trial

OBJECTIVE: The study aimed to analyse the effects of experimental gingivitis on crevicular prostaglandin E(2) (PGE(2)). An increase of PGE(2) was expected. METHODS: Fourteen medical students refrained for 28 days from any oral hygiene procedures in two antagonistic quadrants while they maintained close to perfect oral hygiene in the remaining quadrants. Crevicular fluid samples were taken at baseline and at days 7, 14, 21 and 28 of experimental gingivitis both from quadrants with and without oral hygiene. PGE(2)-concentrations (ng/ml) and absolute levels (pg/sample) were analysed for quadrants with and without oral hygiene. RESULTS: Comparison of quadrants with and without oral hygiene by repeated measures anova revealed no effects of experimental gingivitis both on crevicular PGE(2)-concentrations and absolute levels. CONCLUSION: The study does not support the notion that experimental gingivitis induces an increase of crevicular PGE(2). The data are discussed in the context of other studies on PGE(2) concentrations in gingivitis. Close inspection of these studies reveals no clear evidence for an increase of local PGE(2) in gingivitis.     

Concentration of interleukin-1beta and neutrophil elastase activity in gingival crevicular fluid during experimental gingivitis

BACKGROUND, AIM: The aim of the present study was to measure interleukin-1beta concentrations and neutrophil elastase activity in gingival crevicular fluid (GCF) during experimental gingivitis in humans. MATERIAL AND METHODS: 12 healthy young men participated. After prophylaxis, they performed optimal hygiene to reach plaque and gingivitis indices of or approaching zero. All oral hygiene measures were then ceased for a period of 18 days. The Quigley-Hein plaque index (PLI) and Saxer & Mühlemann papillary bleeding index (PBI) were assessed. GCF samples were taken from the mesiobuccal site of two contralateral teeth in the upper jaw by means of periopapers at baseline and on days 3, 7, 14 and 18. After measuring the gingival crevicular fluid volume (GCFV) with the Periotron 8000, the samples were analyzed in our laboratory for the detection of IL-1beta concentration by ELISA. RESULTS: PLI and PBI showed a reduction prior to baseline reaching almost zero, both increasing from day 0 to day 18 (PLI=from 0.1 to 2.9, PBI=from 0 to 2.0). IL-1beta concentration increased from 229.25 ng/ml (day 0) to 526.13 ng/ml (day 18). Clinical data and IL-1beta concentrations were correlated with elastase activity (EA). No significant correlation could be demonstrated between the clinical parameters assessed and IL-1beta or EA (Spearman rank correlation coefficient). A correlation between GCFV and PBI from day 0 to day 18 could be demonstrated. CONCLUSION: Overall, both IL-1beta and EA showed an increase from baseline throughout the whole study.     

Dental biofilm, gingivitis and interleukin-1 adjacent to approximal sites of a bonded ceramic

AIM: The aim of this study was to investigate in vivo the influence of aged, resin-bonded, ceramic restorations on approximal dental biofilm formation and gingival inflammatory response, associated with and without customary oral hygiene. MATERIAL AND METHODS: In a cross-sectional and in a 10-day experimental gingivitis study, Quigley-Hein plaque index, gingival index (GI), crevicular fluid and its levels of interleukin (IL)-1alpha, -1beta and receptor antagonist were measured at appoximal surfaces of leucite-reinforced bonded ceramic coverages, resin composite restorations and enamel and compared intra-individually in 17 participants. RESULTS: No differences were found between the ceramic, composite and enamel regarding plaque index, GI, levels of IL-1alpha, -1beta and the receptor antagonist. Throughout, higher crevicular fluid amounts were observed at ceramic sites compared with the enamel (p<0.05). In the experimental gingivitis, plaque index, GI, crevicular fluid and its IL-1alpha levels increased significantly. CONCLUSION: The need for optimal oral hygiene and professional preventive oral health care does not seem to be reduced with regard to approximal surfaces of aged, resin-bonded, leucite-reinforced ceramic restorations in comparison with those of a hybrid, resin composite and enamel.     

Comparison of experimental gingivitis with persistent gingivitis: differences in clinical parameters and cytokine concentrations

BACKGROUND AND OBJECTIVE: Experimental gingivitis has been studied extensively as a well-controlled laboratory model of gingivitis. It is unclear, however, how experimental gingivitis compares with persistent plaque and gingivitis in more naturalistic settings. The present study compares both conditions in a randomized controlled design. MATERIAL AND METHODS: Twenty-six students suffering from plaque and gingivitis were randomly assigned to either a persistent gingivitis or an experimental gingivitis condition. Subjects with persistent gingivitis continued their habitual (i.e. insufficient) oral hygiene behaviour, resulting in persistence of plaque and gingivitis. Experimental gingivitis consisted of initial prophylaxis and subsequent total neglect of oral hygiene. Crevicular interleukin-1beta and interleukin-8 and clinical data were assessed weekly. RESULTS: After 4 wk, subjects with experimental gingivitis showed significantly more plaque accumulation (p = 0.005), higher interleukin-1beta (p = 0.037), and lower interleukin-8 (p = 0.043) concentrations than subjects with persistent gingivitis. Whereas in experimental gingivitis we observed considerable fluctuations in clinical and immunological parameters over the 4-wk period, persistent gingivitis was characterized by little fluctuation, indicating that we were monitoring an inflammatory steady state. CONCLUSION: The data indicate that conditions observed after 4 wk of experimental gingivitis are not comparable with persistent gingival inflammation in a naturalistic setting. Results are discussed with respect to current studies, indicating that chronic inflammation may reflect a stage of down-regulated pro-inflammatory response.     

Systemic neutrophil response resulting from dental plaque accumulation

BACKGROUND: There is considerable current interest in putative relationships between oral and systemic diseases. Since the host response to oral bacteria may be the critical link in this association, our hypothesis was that dental plaque accumulation in healthy subjects would elicit a systemic inflammatory response. METHODS: Twenty-three healthy subjects, aged 18 to 25, participated in a 4-phase study. An initial hygiene phase was followed by a 21-day experimental phase (the so-called experimental gingivitis model) in which subjects refrained from all oral hygiene practices, thus permitting the accumulation of bacterial plaque. At days 0, 7, and 21 total and differential peripheral white blood cell (wbc) counts, together with full mouth plaque and gingivitis scores, were recorded. Following a 28-day recovery phase, in which normal oral hygiene practices were resumed, subjects entered the final 21-day control phase which mirrored the experimental phase but with subjects maintaining normal oral hygiene practices. RESULTS: The experimental model performed as anticipated with a correlation between plaque and gingivitis scores of 0.95, also reflecting subject compliance. Total wbc and neutrophil counts increased during the experimental phase. Furthermore, comparison of neutrophil counts between the experimental and control phases demonstrated a significantly higher cell count for the experimental phase on both days 7 and 21 (P= 0.0301 and 0.009, respectively). For total wbc, this was significant on day 21 (P= 0.0262). CONCLUSION: The results of this study support the hypothesis that the accumulation of dental plaque can result in a measurable systemic inflammatory response, providing further in vivo data to support a mechanistic relationship between oral and systemic pathology.     

Preventive action of short-term and long-term chlorhexidine rinses

The purpose of this study was to evaluate the effects of 0.12% chlorhexidine mouthrinses on the presence of plaque and gingivitis, either used as the only oral hygiene practice during a short period of time (21 days) or associated with routine daily brushing for 180 days. The experimental subjects were 40 dental students of an average age of 20.9 years. Following a thorough examination and mechanical prophylaxis. The subjects were divided into two treatment groups. Twenty subjects stopped all oral hygiene procedures for 21 days except for twice-daily rinses with 0.12% chlorhexidine or a placebo. Plaque, gingivitis scores and oral soft tissue health were recorded on days 0, 7, 14 and 21 for the short term group and on days 0, 90 and 180 of experimentation for the long term group. After 21 days of rinsing, plaque accumulation, gingivitis and bleeding on probing were significantly lower in the chlorhexidine group than in the placebo group. After three and six months of mouthrinses, the chlorhexidine group had less plaque and significantly less gingivitis than the placebo group. No significant differences in adverse oral soft tissue effects were observed between the different groups. It was concluded that a 0.12% chlorhexidine digluconate mouthrinse can provide an important adjunct to the prevention and control of gingivitis when used as the only oral hygiene practice or with regular personal hygiene procedures. The results obtained in this clinical study, using stringent parameters of evaluation with statistic analysis, corroborated the results obtained by other studies.     

TNF-alpha TGF-beta2 and IL-1beta levels in gingival and peri-implant crevicular fluid before and after de novo plaque accumulation

Aims: The aim of this split‐mouth study was to investigate levels of tumour necrosis factor alpha (TNF‐α), transforming growth factor beta (TGF‐β2) and interleukin‐1 beta (IL‐1β) in gingival crevicular fluid (GCF) and peri‐implant crevicular fluid (PICF) after a 21‐day‐period of de novo plaque accumulation in the same patient. Material and Methods: In 25 patients, samples of GCF and PICF were collected in the sulcus of the tooth and of the implant after professional hygiene. After the no‐hygiene phase (21 days), second samples of GCF and PICF were taken. Third samples were collected after 69 days of re‐establishment oral hygiene techniques. The crevicular fluids were used to determine the volume and the levels of TNF‐α, TGF‐β2 and IL‐1β. Results: The volume of the crevicular fluids increased significantly after 21 days of plaque accumulation around teeth and implants and decreased significantly by 69 days. TNF‐α and TGF‐β2 did not change significantly among the three different samples. A significant increase of IL‐1β was observed after plaque accumulation around the teeth GCF, whereas in the PICF the increase was not statistically significant. Conclusions: These data suggest that increased volumes of GCF and PICF could be useful markers of early inflammation in gingival and peri‐implant tissues. In the presence of de novo plaque, implants showed lower, and nearly significant, levels of IL‐1β compared with teeth.     

Development of gingivitis in pre-school children and young adults

Earlier studies suggest that children and adults differ in the propensity to develop gingivitis when oral hygiene is abandoned. To confirm the existence of such a difference, a comparative study of pre-school children and young adults was made with objective registration methods. The author performed all registrations. After a period of intensive oral hygiene, all cleaning of teeth was discontinued for 21 days. The amount of bacterial plaque, the amount of gingival exudate and crevicular leukocytes and the bleeding tendency were registered on days 0, 7, 14 and 21. During the experiment the amount of bacterial plaque increased continously in both groups. The amount of gingival exudate and the tendency to gingival bleeding increased to high values in the adults, while only a small rise was seen in the children. The amount of crevicular leukocytes increased in both groups, but the increment was greater in the adults. A comparison concerning differences in gingival exudate and bleeding tendency between pre-school children and adults was undertaken for gingival units that showed a similar plaque development. Under these statistically acceptable prerequisites, it was shown that there is a real difference in the tendency to develop gingivitis between pre-school children and adults.     

Studies of host responses during experimental gingivitis in humans

The aim of the study was to find out whether autologous supragingival plaques collected at various times during the development of experimental gingivitis in men differ in their potential to induce PMN responses in vitro. Ten subjects refrained from all oral hygiene for a period of 21 days. At day 0, Day 3 and Day 21 after cressation of oral hygiene clinical indices (plaque index, gingival index, gingival crevicular fluid flow) were assessed plaque was collected at day 3 and Day 21 after cessation of Oral hygiene clinical indices (plaque index, gingival index, gingival crevicular fluid flow) were assessed plaque was collected at Day 3 and Day 21. PMNs, isolated from peripheral blood 1–2 months after the non-brushing period were incubated with the various autologous plaques in the presence or the absence of autologous serum. Supernatants of cell cultures were monitored for extracellular release of lysosomal constituents, viz. lysozyme, myeloperoxidase and lactoferrin. There was no difference in the amounts of lysozyme, myeloperox dase and lactoferrin. There was no difference in the amounts of lysozyme or myeloperoxidase released by PMNs. The inclusion of fresh serum enhanced PMN release reactions but there was no significant differences in the relative capacity of Day 0, Day3 and Day 21 sera to modulate PMN responses. A statistically significant positive correlation was established betwen the magnitude of lactoferrin release from PMNs exposed to Day 3 plaque and the gingival fluid flow recorded on Day3. Lactoferrin is segregated in the specific granules of the PMNs which also contain other cationic proteins, collagenases and neutral proteinases. These data suggest that a possible causal relationship may exit between the release of PMN constituents and the development of inflammation during the early phases of gingivitis.     

Effect of a novel ceramic filling material on plaque formation and marginal gingiva

The aim of this clinical investigation was to evaluate a novel ceramic (CF) filling material (DoxaDent) compared to resin composite (RC) and enamel in regard to plaque formation and gingival inflammation. The CF material is inorganic, non-metallic, and contains calcium aluminate, silicate, and water. To make intra-individual comparisons possible, each participant had at least one set of three test surfaces: two Class V restorations with subgingival cervical margins (one of the novel CF material and one of a hybrid RC) and one non-filled enamel surface (E). The amounts of plaque, gingival crevicular fluid, and clinical signs of gingival inflammation were intra-individually compared in 20 sets of the three test surfaces. In a cross-sectional study (CSS), the effect of oral hygiene on plaque formation and gingivitis around the surfaces was evaluated. In a following 10-day experimental gingivitis study (EGS), plaque formation and the induction of gingivitis during refrain from oral hygiene was compared. In the CSS, no significant differences were found between the surfaces in terms of amount of plaque and degree of gingival inflammation. At the end of the EGS the restorative materials showed a significantly higher amount of plaque (CF versus E, P = 0.014; RC versus E, P = 0.034), but no significant differences were found in degree of gingival inflammation. In condusion, the ceramic filling material was comparable to RC regarding plaque formation and gingival inflammation with customary oral hygiene. With neglected oral hygiene, significantly less plaque growth and a non-significant tendency toward lower amounts of gingival crevicular fluid were observed on enamel surfaces.     

The effect of locally released oxygen on the development of plaque and gingivitis in man

Abstract An experimental gingivitis study was designed to test the effect of a 5-min twice daily oxygen application on the development of plaque and onset of gingivitis A method for the local application of medical grade oxygen to the upper anterior teeth was developed, with the lower anterior teeth used as controls. Fourteen periodontally healthy dental students of average age 21.9 years participated in the study. There was no significant effect of oxygen on plaque formation, crevicular fluid flow, or the number of gingival bleeding sites. Experimental and control gingival segments exhibited bleeding on probing at an average of 6.6 days after cessation of mechanical plaque control, much earlier than reported in other experimental gingivitis studies.     

Effect of smoking on gingival crevicular fluid cytokine profile during experimental gingivitis

BACKGROUND: Cigarette smoking is a significant risk factor in the pathogenesis of periodontal disease, able to influence both the subgingival microbiota and host responses. AIM: The aim of the present study was to determine the influence of smoking on the amount of IL-1beta, IL-4 and IL-8 in gingival crevicular fluid (GCF) during experimental gingivitis in humans. MATERIAL AND METHODS: Twenty-two healthy subjects, 10 smokers and 12 non-smokers, participated in the study. After professional cleaning, they performed optimal hygiene to reach perfect clinical gingival health. Oral hygiene measures were ceased for a period of 10 days. Clinical indices, including plaque index (PI), gingival index (GI), probing pocket depth (PPD) and bleeding on probing (BOP), were assessed 2 days before (day -2), at the beginning (day 0) and at the end of the experimental gingivitis period (day 10). At the same time, GCF was collected from 12 sites in each patient, by means of durapore filter membranes. Total amounts of IL-1beta, IL-4 and IL-8 were determined by enzyme-linked immunoadsorbent assay. RESULTS: Clinical data revealed that both smokers and non-smokers showed an increase in PI, GI and BOP scores during the experiment. Although no differences were noted with regard to PI at day 10, the GI and BOP were significantly less pronounced in smokers than non-smokers (p < 0.005). Non-smokers showed higher total amounts of IL-4 but lower amounts of IL-8 than smokers, throughout the experiment. Total amounts of IL-1beta and IL-8 increased significantly during plaque accumulation in both groups. IL-4 remained stable for the smoker group and decreased for the non-smoker group. CONCLUSIONS: The present results indicate that smoking interferes with cytokine production. When performing studies regarding the pathogenesis of periodontitis, the smoking status of the participants needs to be taken into consideration.     

Microcirculatory dynamics in experimental human gingivitis

Abstract The purpose of this study was to determine the changes that occur in the gingival microcirculation during the development of experimental gingivitis in humans. There have been no studies published to date combining videomicroscopy and laser Doppler flowmetry to study vascular dynamics in experimental gingivitis. Alterations occurring in the microcirculation of the marginal gingiva in 10 (18–30-year-old), healthy male humans when they suspended oral hygiene procedures in a proscribed area for 12–16 days were monitored. A partial mouth, experimental gingivitis model was employed. Gingival health was evaluated before and after the experimental period by assessing gingival and plaque indices and gingival crevicular fluid volume. Gingival vascular monitoring included measurement of red blood cell velocity in individual gingival microvessels via video-microscopy and measurement of regional gingival blood flow using laser doppler flowmetry. The number of vessels visible in a given microscopic field in a given subject and the number of vessels exhibiting flow were also determined from the videotapes. Systemic cardiovascular and respiratory parameters were monitored to ensure that gingival vascular changes were not secondary to systemic changes. Gingivitis developed in all subjects; significant increases (Student t-test, P < 0.05) were seen in plaque index, gingival index, bleeding on probing and crevicular fluid volume. No change in superficial capillary blood velocity and a significant decrease in gingival regional blood flow were seen with gingivitis. A significant increase in the number of vessels visible in microscopic fields and a decrease in the % of vessels exhibiting flow were observed. Gingival microcirculation exhibited a dramatic, dynamic change in response to the development and progression of gingivitis.     

The effect of a cetylpyridinium chloride (CPC) detergent foam compared to a conventional toothpaste on plaque and gingivitis

A CPC-detergent formulation in a foam vehicle, was compared with a fluoride toothpaste for its ability to prevent plaque and gingivitis over a period of 12 days. Whilst refraining from all other oral hygiene procedures, the foam or toothpaste was applied to the teeth in fluoride application trays, in a group of 14 volunteers. At days 8 and 12 of this crossover study, the following assessments were made: gingival crevicular fluid; gingival index; bleeding on probing; plaque index; plaque area. Except for plaque area at day 8 of the study, there were no significant differences between the 2 products at either day 8 or day 12. It is therefore concluded that the CPC-detergent formulation, in its present form, does not inhibit plaque and gingivitis more effectively than a conventional fluoride toothpaste.     

Experimental gingivitis studies: effects of triclosan and triclosan-containing dentifrices on dental plaque and gingivitis in three-week randomized controlled clinical trials

A recently reported six-month gingivitis study demonstrated that in subjects with gingivitis, a triclosan/pyrophosphate dentifrice provided supragingival plaque control. The level of plaque reduction was comparable with that reported for other triclosan-containing dentifrices; however, no reductions in gingivitis were observed for triclosan/pyrophosphate relative to the negative control. One possible explanation of this result is that the Hawthorne effect in the study was too great to allow the detection of a treatment benefit for the triclosan product. In order to further explore the relevance of these results, three independent clinical studies were undertaken utilizing designs based on a 21-day experimental gingivitis model in which Hawthorne effects are minimized, in part due to the absence of toothbrushing. In each model, a pre-study prophylaxis was followed by a three-week period of oral hygiene instruction to establish optimum baseline gingival health in study participants. The studies varied in enrollment; 120, 33 and 32 subjects completed treatment on studies 1, 2, and 3, respectively. In study 1, test articles were dentifrice products (0.28% triclosan/5% pyrophosphate/0.145% sodium fluoride, 0.2% triclosan/0.5% zinc citrate/0.112% sodium fluoride, 0.145% sodium fluoride and 0.15% sodium monofluorophosphate) applied neat and undiluted via a performed tooth shield (that prevents mechanical tooth-brushing at the test sites in the oral cavity) in a partial mouth design. In study 2, test articles were also dentifrice products (0.28% triclosan/5% pyrophosphate/0.243% sodium fluoride, 0.3% triclosan/2% Gantrez copolymer/0.24% sodium fluoride and 0.243% sodium fluoride) but administered to subjects in the form of 1:3 aqueous slurry rinses. Lastly, in study 3, test articles were all mouthrinses (0.12% chlorhexidine, 0.045% triclosan in ethanol plus respective vehicle placebos). Clinical assessments to quantify the test articles' effects on the development of plaque and gingivitis were conducted at baseline (studies 1, 2 and 3), day 7 (studies 2 and 3), day 14 (studies 2 and 3) and day 21 (studies 1, 2 and 3). In study 1, no statistically significant treatment effects were observed between the test articles and controls for plaque or gingivitis development. In study 2, no statistically significant treatment effects were observed at any time point between test products for the development of gingivitis. At days 7 and 14, there were no significant differences between test products and control for plaque development as well. At day 21, the group rinsing with the triclosan/pyrophosphate/sodium fluoride slurry had significantly less plaque accumulation than the group rinsing with the triclosan/copolymer/sodium fluoride slurry (p < 0.05); however, neither of the groups using test products containing triclosan was significantly different for plaque development from the group using the sodium fluoride control test article. In addition, aspartate aminotransferase activity in gingival crevicular fluid was assayed at days 0 and 21; no between-group differences were found at either of these time points, though day 21 AST activities were higher than those at baseline. In study 3, statistically significant treatment differences in plaque regrowth and gingivitis were observed at day 21 for the chlorhexidine rinse versus all other rinses (p < 0.05). No other statistically significant treatment effects were observed between test compounds at any other time points. The results benchmark the anti-plaque and anti-gingivitis benefit for a range of triclosan-based product forms against positive and negative controls in a three different experimental gingivitis models, a design considered predictive of clinical efficacy in longer-term investigations. It is concluded that dentifrice products containing triclosan do not possess sufficient antimicrobial activity to suppress plaque and gingivitis development in the absence of normal oral hygiene, and that relative to chlorhexidine, triclosan itself offers only modest efficacy for the prevention of plaque accumulation and therefore the delayed onset of gingivitis.     

The influence of gingival stimulation on recovery from human experimental gingivitis

The present study concerns an investigation carried out to determine the effects of gingival stimulation on the resolution of a human experimental gingivitis. 10 young male dental students participated in the experiment. Following the baseline examination (day 0), the participants were instructed to abstain from all oral hygiene procedures during a 21-day period. Heavy plaque accumulation and gingivitis developed during the 21-day induction period. On the evening of the 21st day, active oral hygiene measures were reinstitued, for an 8-day period, using 2 different methods. For the left side of the maxillary arch, a hygiene procedure including gingival stimulation was prescribed. On the other hand, for the right side, a hygiene method without gingival stimulation was instituted. On both sides of the upper arch, the gingival condition was assessed by means of the gingival index, and soft deposits were assessed by the plaque index (selected teeth: 13, 14, 15, 23, 24, 25). Measurements were performed on days 0, 21, 22, 23, 24, 25, 26, 27, 28, 29. On day 29, ideal oral hygiene conditions and gingival health were re-established on both sides. However, a statistical analysis of the data collected during the recovery period revealed that gingival index scores were temporarily, but significantly, higher on the side where mechanical stimulation was performed, although plaque deposits there decreased more rapidly. Thus the present work supports the idea that gingival stimulation does not in any way improve recovery from experimental gingivitis.     

Development of experimental gingivitis in the juvenile and adult beagle dog

Abstract. In a previous paper a lower tendency to develop gingivitis was reported among preschool children compared to adults. The aim of the present study was to clarify if the same age-dependent difference exists in dogs.
Six beagle dogs from the same litter were used. two periods of discontinued oral hygiene were studied, one period when the dogs were 3 months old and the other at 12 months. Prior to and between the experimental periods the animals were subjected to meticulous toothcleaning. During the experimental periods the Gingival and Plaque Index scores as well as the amounts of gingival exudate and crevicular leukocytes were determined on days 0, 4, 7, 14, 21 and 28.
During the juvenile period the development of dental plaque was lower compared with the adult period. The frequency of gingival units with high Gingival Index scores was lower at every registration interval during the juvenile period. The amounts of gingival exudate and crevicular leukocytes increased to high values during the adult stage but only small increments were found in the juvenile stage. An intraindividual comparison of the increase in the amount of gingival exudate from day 0 to day 28 in areas with the same amount of dental plaque accumulation showed a lower increase in gingival exudate during the juvenile stage in all dogs.