Plaque Index System Research Articles

Dental Caries Severity in Relation to Selected Salivary Variables among a Group of Pregnant Women in Baghdad City, Iraq

Background: During pregnancy many physiological, anatomical and biochemical changes take place that affect almost all body systems. In the oral pregnant women have serious changes such as more sever dental caries. This study was conducted to measure dental caries severity and selected salivary variables (salivary flow rate, PH and viscosity)and to find the relation of dental caries with these salivary variables. Subjects, materials and methods: The study group consisted of 60 pregnant women that were divided into three equal groups according to trimester (20 pregnant women in each trimester).They were selected randomly from the Maternal and Child Health Care Centers in Baghdad city, the age range was 20-25 years. In addition to 20 unmarried women as a control group and matched with age. Stimulated salivary samples were collected .Then salivary flow rate, pH and viscosity were measured. Dental caries severity was recorded by using Decay, Missing and Filled index (D1-4MFS) using the criteria described by Manjie et al, (1989). Plaque index system by Silness and Löe, (1964) was used for measuring dental plaque thickness. For measuring dental calculus the calculus index component of the periodontal diseases index (PDI) by Ramfjord (1959) was used. Results: Results of the current study revealed that dental caries parameter represented by (DMFT ,DMFS,DS and MS) were higher among pregnant than non –pregnant women with significant differences (p0.05).Almost all dental caries parameter were higher in the 2nd trimesters with highly significant difference (p

구강건강관리행위에 따른 치면세균막지수와의 관련성

구강건강관리행위의 실태를 파악하고, 치면세균막 검사법에 따른 치면세균막지수의 차이와 이 둘의 상관성을 조사하기 위해 2013년 10월부터 2014년 10월까지 경기도와 충청남도에 소재한 3개 대학의 치위생과 학생을 대상으로 자기기입식 설문지 작성과 치면세균막지수를 각각 측정하여 진행하여 다음과 같은 결론을 얻었다. 1년 이내에 구강검진을 받았다고 응답한 대상자는 62.8%, 예방치과처치를 한 번이라도 받아봤다고 응답한 대상자는 84.1%로 조사되었다. 불소가 포함된 세치제를 사용하고 있다고 응답한 대상자는 80.5%였으며, 칫솔질은 하루에 3회 한다고 응답한 대상자가 68.9%로 가장 높게 나타났다. 칫솔질 방법은 회전법이, 칫솔질 시간은 3분이 각각 90.9%, 50.0%로 조사되었다. 치면세균막 검사법 중 O'leary index로 조사한 결과 평균 27.88로 조사되었으며, PHP index는 평균 1.30, PHP-M index는 평균 12.12로 조사되었다. 구강건강관리행위에 따른 치면세균막지수는 칫솔질 시간이 통계적으로 유의한 차이를 보이는 것으로 조사되었다. 칫솔질 시간이 2분 이하일 경우 O'leary index 31.37, PHP index 1.61, PHP-M index 14.61로 조사되었으며, 4분 이상일 경우 O'leary index 23.32, PHP index 1.07, PHP-M index 9.59로 조사되어 칫솔질 시간이 늘어날수록 치면세균막지수는 낮아지는 것으로 나타났다(p<0.05). 치면세균막지수에 가장 영향을 미치는 요인은 "구강건강을 위한 칫솔질 여부" (B=-9.747, t=-3.752, p<0.001)로 나타났으며, 이는 통계적으로 유의한 차이를 보였다. 설명력은 O'leary index 13.3%, PHP index (B=-0.375, t=-3.016, p=0.003)와 PHP-M index (B=-4.541, t=-3.708, p<0.001)는 각각 12.3%, 17.5%로 조사되었다. 이상의 결과를 정리해보면, 치면세균막지수에 영향을 미치는 구강건강관리행위는 칫솔질 시간과 구강건강을 위한 칫솔질 여부로 조사되었다. A self-administered survey was conducted on the dental hygiene students at three different colleges located in Gyeonggi Province and South Chungcheong Province respectively from October, 2013, to the same month of 2014 to grasp their oral health management behavior, differences in plaque index according to plaque index systems and the correlation of the two. And their plaque index was measured. The findings of the study were as follows: 62.8% of the respondents replied they got a dental checkup over the past year, and 84.1% answered they received preventive dental treatment once at least or more. 80.5% replied they used a fluorine-containing dentifrice. 90.9% answered they used the rolling method to brush their teeth, and 50.0% replied it took three minutes to brush their teeth. They got a mean of 27.88 when O'leary index was used among plaque index systems. Their PHP index and PHP-M index were respectively a mean of 1.30 and a mean of 12.12. Their plaque index became lower when they spent more time brushing their teeth, and the toothbrushing time made a statistically significant difference to that (p<0.05). The factor that exerted the largest influence on plaque index was whether to brush teeth for the sake of oral health (B=-9.747, t=-3.752, p<0.001) or not. That made a statistically significant difference to it. The above-mentioned findings illustrated that more patients visited dental clinics than before to receive preventive dental treatment or to get dental checkups, and that toothbrushing time and whether to brush teeth for the sake of oral health or not were identified as the oral health management behaviors to affect plaque index.

The association between dental and periodontal diseases and sickle cell disease. A pilot case-control study.

ObjectiveThis is a pilot case-control study conducted to investigate the prevalence of dental caries and periodontal disease and examine the possible association between oral health deterioration and SCD severity in a sample of Saudi SCD patients residing in the city of Al-Qatif, Eastern Province, Saudi Arabia.Materials and methodsDental examination to determine the Decayed, Missing and Filled Teeth index (DMFT), Community Periodontal Index (CPI), and plaque index system were recorded for 33 SCD patients and 33 age and sex-matched controls in the Al-Qatif Central Hospital, Qatif, Saudi Arabia. Self-administered surveys used to assess socio-economic status; oral health behaviors for both SCD patients and controls were recorded. In addition, the disease severity index was established for all patients with SCD. SPSS data analysis software package version 18.0 was used for statistical analysis. Numerical variables were described as mean with a standard deviation.ResultsDecayed teeth were significantly more in individuals with ages ranging from 18 to 38 years with SCD compared to the control group (p = 0.036) due to oral hygiene negligence. The mean number of filled teeth was significantly lower in individuals with SCD when compared to the control group (p = 0.015) due to the lack of appropriate and timely treatment reflected in the survey responses of SCD patients as 15.2% only taking oral care during hospitalization. There were differences between the cases and controls in the known caries risk factors such as income level, flossing, and brushing habit. The DMFT, CPI, and plaque index systems did not differ significantly between the SCD patients and the control group.ConclusionData suggest that patients with SCD have increased susceptibility to dental caries, with a higher prevalence of tooth decay and lower prevalence of filled teeth. Known caries risk factors influenced oral health more markedly than did factors related to SCD.

Effect of mouth wash extracted from Salvadora persica(Miswak) on dental plaque formation: A clinical trail

Chewing sticks or Miswak are used for teeth cleaning in many parts of the world, these Miswaks are believed to contain chemical substances which inhibit plaque formation and gingivitis. In the present study, Salvadora persica (Miswak) was extracted with 60% ethanol and was examined for its toxic effect, assessed its antibacterial activity and evaluated clinically for its effect on dental plaque formation. A 4 day plaque regrowth, double - blind, crossover design was used in which 10 dental students volunteers were rendered plaque free (0.3), ceased tooth cleaning, then, asked to rinse twice daily for 1.5 min each time with 10 ml of chlorhexidine 0.2% mouth rinse and three times daily for 1.5 min each time with 10 ml of S. persica 10% solution and placebo mouth rinse. On day five, plaque was scored by the plaque index system (PLI). A wash out period of 2 days was allowed in which the volunteers returned to self- performed plaque control, then a new test period was initiated. Statistical analysis showed that the mean PLI score were 1.48 for S. persica mouth rinse, 0.48 for chlorhexidine and 2.07 for placebo mouth rinse. Acute toxicity test revealed no mortality among the experimental animals which is an indication that S. persica crude extract solution is well tolerated, disk diffusion test showed a marked antibacterial effect in vitro and this effect is concentration dependent, had an effect in in vivo, but this effect cannot be considered absolute.

Azithomycin as an adjunctive to non-surgical treatment in comparison with doxycycline in chronic periodontitis patients: 2-months randomized clinical trial

Background: Antibiotic therapy can be used in very specific periodontal treatment situations such as in refractory cases of periodontal disease which is found to be more prevalent in smokers. The aim of study was to asses the clinical effect of systemic use of Azithromycin and Doxycycline as adjunctive to non surgical scaling and root planning in patients with chronic periodontitis. Materials and methods: The study participants were 21 adult male, divided to three groups. 1n: GI treated by non surgical root planning with systemic intake of Azithromycin of 500 mg once daily for three days only. In GII Doxycycline 100mg once daily was given for one week in addition to non surgical root planning while in the G III (control group) the patients were treated only by a routine scaling and root planning with out using any type of drug. .The periodontal parameters used are the following:- Plaque index system(PLI) Gingival index (GI),Probing pocket depth (PPD) and Bleeding on probing (BoP) Results: The study based on three periodontal parameters to asses the results of study, first of which is plaque index and there was a significant low in all groups from the base line until the 4th visit while the bleeding on probing showed a highly significant difference between the groups whom take antibiotics as an adjunctive to a non surgical treatment and the group with out antibiotics. While for probing pocket depth the difference was only between the groups whom take Azithromycin and control group this difference was start in the 2nd visit until the last visit Conclusion: Although both treatment strategies seemed to be a successful therapy, the adjunctive use of 500 mg azithromycin systemically enhanced the clinical results.

The effect of systemic administration of ibuprofen in the experimental gingivitis model

Studies in humans have indicated that systemically administered flurbiprofen and ibuprofen may reduce gingivitis. De novo plaque formation is enhanced at tooth surfaces adjacent to inflamed gingivae. The aim of the present clinical trial was to evaluate the effect of systemic administration of ibuprofen on gingivitis and plaque build-up. Eleven subjects were recruited for the study and were given oral hygiene instruction, scaling and professional mechanical tooth cleaning (PTC). At the end of a preparatory period (Day 0), the participants were told to abstain from all mechanical plaque control measures during a 2-week experimental period but to rinse with an assigned mouth rinse (positive control: 0.1% chlorhexidine digluconate; negative control: saline) or administer ibuprofen (tablets of 200 mg twice daily). Mouth rinsing was performed twice a day (after breakfast and in the evening), for 60 s with 10 ml. Re-examination was performed after 14 days of experiment. After a 2-week "wash-out" period, the participants received a new PTC and a second 14-day experimental period was initiated. The experimental and "wash-out" periods were repeated until all volunteers had been involved in all three regimens. Dental plaque was scored using the Quigley & Hein Plaque Index system and gingivitis according to the Gingival Index (GI) system. Supragingival plaque was collected and prepared for dark-field microscopy. One hundred bacterial cells were counted and classified into six different groups: coccoid cells, straight rods, filaments, fusiforms, spirochetes and motile rods. Gingival crevicular fluid (GCF) was collected from the same sites that were sampled for plaque. The volume of GCF collected in each strip was measured and analysed regarding content of lactoferrin and albumin. During the period when the panelists rinsed with saline they accumulated large amounts of plaque and developed marked signs of gingivitis. When they rinsed with chlorhexidine digluconate, small amounts of plaque formed and few sites received GI score > or =2. After the 2 weeks of ibuprofen administration, the panelists presented with significantly fewer sites that scored GI > or =2 but had formed similar amounts of plaque as during the negative control period. It is suggested that ibuprofen administered via the systemic route has an effect on gingivitis but not on de novo plaque formation.

Longitudinal relationship between incisal tooth wear and periodontal condition.

The purpose of the study was to examine the relationship between the longitudinal development of incisal tooth wear and periodontal conditions in 51 persons. Stone casts obtained at the ages of 15 and 27 yr were used to assess incisal wear according to a graded scale, the Incisal wear Index (IwI). The wear increase after 12 yr, delta IwI, was related to the various health index scores at the age of 15 yr, including the Plaque Index (PlI) and Gingival Index (GI) systems. The chi-square tests showed a statistically significant association between delta IwI and periodontal condition in 15-yr-olds. Thus, relatively low PlI and GI values were accompanied by relatively high delta IwI values. It was concluded that in 15-yr-olds, PlI and GI levels are clinical predictors of future wear (delta IwI) of maxillary and mandibular central incisors. Pocket depth (PD) was a less valuable clinical predictor of such wear.

Bleeding on probing as it relates to probing pressure and gingival health in patients with a reduced but healthy periodontium. A clinical study.

A previous study demonstrated that the bleeding on probing (BOP) test using uncontrolled forces may result in a proportion of false positive readings when used as a parameter for inflammation. A strong possibility exists for the traumatization of clinically healthy gingival tissues if a probing force exceeding 0.25 N is applied. While these results originated form young dental hygienists exhibiting excellent oral hygiene, the aim of the present study was to evaluate the relationship between probing pressures and gingival conditions in patients with a history of treated periodontal disease, i.e., in situations with a reduced but healthy periodontium. 10 patients who had been enrolled in a periodontal maintenance program following treatment of moderate to advanced chronic inflammatory periodontal disease consented to participate in the study. They were all selected on the basis of a record of excellent oral hygiene practices for at least 2-6 years and almost complete absence of clinical inflammation following successful periodontal therapy. Applying a probing force of 0.125, 0.25, 0.375 and 0.5 N in the 4 jaw quadrants, respectively, at 2 different occasions with an interval of 10 days, bleeding on probing was assessed. Oral hygiene and gingival conditions were determined using the criteria of the plaque and gingival index systems. All subjects showed significant increases in mean BOP% with increasing probing force applied (2.5%-7.9%). Regression analysis revealed an almost linear correlation and a significant correlation coefficient between BOP% and probing force. Almost identical slope inclinations were found when the 6 subjects with the lowest mean BOP% at 0.25 N were compared with the regression analysis of the total group.(ABSTRACT TRUNCATED AT 250 WORDS)

A model for studying the effects of mouthrinses on de novo plaque formation.

The aim of the present study was to describe a 4-day no oral hygiene model to assess the pattern of de novo plaque formation and to use this model to appraise the potential of some mouthwash preparations to retard or inhibit plaque formation in the human dentition. 10 subjects were recruited for the trial. During a preparatory period, the participants were exposed to repeated professional plaque control and given oral hygiene instruction to eliminate signs of gingivitis. At the end of the preparatory period, each participant received a final professional tooth cleaning and was subsequently told to abstain from mechanical plaque control efforts for the next 4 days. They were asked to rinse twice daily for 60 s with 10 ml varying test solutions. On Day 4, the volunteers were exposed to a new clinical examination and the presence and amount of plaque were examined by the use of the plaque index system (P1I). The participants were subsequently given a professional tooth cleaning and asked to exercise proper self performed plaque control during the next 10 days. A new test period was then initiated. 6 different mouthwash preparations were tested in each subject namely, (1) placebo (a negative control rinse), (2) Veadent mouthrinse, (3) Listerine mouthrinse, (4) 0.06% triclosan + polyvinyl phosphonic acid (PVPA), (5) 0.06% triclosan + phenolic flavor and (6) 0.12% chlorhexidine digluconate (a positive control rinse). The results from the study revealed that the mean P1I values for individuals, groups of teeth and tooth surfaces provide an adequate but gross overall estimation of the potential of a given mouthrinse to retard/inhibit plaque build up. More detailed information on the effects of the test rinses could be obtained by data describing the % distribution of different P1I score categories; a high frequency of score 0 describes the potential of a mouthrinse to maintain tooth surfaces free from plaque while a low frequency of score 2/3 describes the ability of a treatment to retard/prevent gross plaque formation. The plaque pattern displays finally allowed assessment of the magnitude of plaque prevention, in comparison to the positive and negative controls, that could be achieved by a given compound in various parts and surfaces of the dentition. In this model, all test rinses (i) were significantly more effective than the placebo rinse in retarding de novo plaque build up and (ii) had a minor effects on plaque build up in the maxillary molars and at the approximal surfaces.(ABSTRACT TRUNCATED AT 400 WORDS)

Patterns of de novo plaque formation in the human dentition.

The objective of the present clinical trial was to carefully assess the pattern of de novo plaque formation in the human dentition. 10 subjects aged 24-29 years were recruited for the study. None of the participants showed signs of destructive periodontitis. At the start of the preparatory period, they were given a thorough dental prophylaxis and oral hygiene instruction. For the next 2 weeks, the participants were carefully monitored and 1 x every 2 days examined with respect to plaque and gingivitis. At the re-examinations, they were also given professional tooth cleaning and instruction in proper plaque control measures. Towards the end of this 2-week period, the Day 0 examination was performed which revealed that the gingival tissues of all participants were in excellent clinical health. Following the Day 0 examination, all 10 subjects were exposed to professional tooth cleaning. During the next 14 days, they abolished all mechanical tooth cleaning efforts but were examined with respect to plaque on Days 1, 4, 7 and 14. The amount of plaque formed was examined using the criteria of the Plaque Index system (PlI). Each of 6 surfaces of each tooth in the dentition was given a score from 0 to 3. The results from the re-examinations demonstrated that in humans with clean teeth and normal gingiva, the abolishment of mechanical tooth cleaning rapidly resulted in de novo plaque formation. Most plaque, as assessed by the plaque index system, formed during the first 4 days of no tooth cleaning after which moderate additional amounts of plaque formed. It was observed that the mean PlI values for individuals, for groups of teeth and tooth surfaces, provide a proper overall estimation of plaque build up. The dynamics of plaque formation between examinations and in different parts of the dentition were more easily disclosed by the data describing % distributions of different score categories and the transition between scores from one examination to the next. The total amount of plaque formed on various tooth surfaces was best presented by so called "plaque pattern displays". The results also revealed that (i) the mandibular dentition harbored more plaque than the maxillary dentition, (ii) there was a difference in the mean PlI scores between the molar and the anterior tooth regions in the maxilla, but in the mandible such a difference could not be observed (except on Day 1), (iii) plaque accumulated most at the approximal surfaces and least at the palatal surfaces, and that (iv) differences in PlI scores between groups of teeth and tooth surfaces observed on Day 4 persisted through the Day 14 examination.

The relationship between pontic hygiene and mucosal inflammation in fixed bridge recipients.

Professional and personal hygiene measures were instituted in bridge recipients who demonstrated subpontic inflammatory lesions of the mucosa. The study group consisted of 16 participants (10 9♂ 6♀) with 27 pontics in all. Criteria of the Plaque and Gingival Index systems were used to describe the occurrence of plaque and mucosai inflammation. Occurrence of mineralized deposits was determined radiographically. Gram‐stained smear preparations were prepared for bacteriological examination. An estimate of the outgrowth of yeasts was obtained by a miniaturized culture test system. After hygiene periods of varying lengths of time, the clinical signs of inflammation disappeared. It is concluded that bacterial plaque is essential for the production of inflammation of the mucosa subjacent to bridge pontics.

Clinical comparison of direct versus indirect bonding with different bracket types and adhesives

A longitudinal clinical trial was made in forty-two children to compare some commonly used techniques for orthodontic bracket bonding. A particular study design (Figs. 1 and 5) allowed blind quadrantwise comparisons in the same patient of six different variables, including direct versus indirect bonding, adhesives of the filled diacrylate resin type with small versus large filler particles, and metal brackets with mesh-backed versus perforated bases. The same person bonded all brackets within one week and performed the orthodontic treatment by a friction-free edgewise light-wire technique. Efforts were made to minimize gingival irritation by using eccentrically placed brackets on small bases, by careful trimming of excess adhesive flash around the bases, and by directing much emphasis on oral hygiene measures. The plaque situation around the brackets and along the gingival margins and the gingival condition were assessed according to the criteria of the plaque and gingival index systems by a dental hygienist at each monthly visit during a test period of 6 months.The study demonstrated that both direct and indirect bonding with the different adhesives and bracket types could give clinically satisfactory results. Still, there were statistically significant differences in plaque retention, gingival inflammation, and bond strength. The bonding adhesive with small filler particles was more hygienic than and about as strong as two adhesives with larger, coarser filler particles. The mesh-backed brackets retained less plaque and gave stronger bonds than the brackets with perforated pads. Advantages of direct bonding over the indirect procedure were that (1) the bracket bases were fitted closer to the tooth surface (which improved bond strength), (2) it was easier to work clean and to remove excess adhesive flash around the bracket bases (to help prevent gingival inflammation and decalcification and facilitate debonding), and (3) the bonding adhesive constantly filled out the entire contact surface of the brackets (thus avoiding artificial undercuts and deficiency areas which are prone to promote decalcification).A number of other clinical observations were also discussed.

Cell mediated immune responses to plaque antigens during experimental gingivitis in man.

The purpose of the present investigation was to evaluate the ability of antigens of human dental plaque microorganisms to stimulate peripheral blood lymphocytes (PBL) from humans during the development and recovery from experimental gingivitis.Eleven healthy dental students (22–36 years) participated in the study. At the start of the experiment, they exhibited clean teeth and clinically healthy gingivae. They then abstained from all oral hygiene measures for four weeks according to the model proposed by Löe et al. (1965). At the start, after 1, 2, 3 and 4 weeks of abolished oral hygience and 2 weeks following reinstitution of oral hygiene, the oral conditions were assessed, using the critieria of the Plaque Index system (Löe &amp; Silness 1964) and the Gingival Index system (Löe &amp; Silness (1963).At each examination triplicate microcultures, each containing 2 × 105 viable PBL in .2 ml TC 199 with glutamine and antibiotics containing 10% fetal calf serum, were stimulated with four concentrations of sonicates from V. alcalescens, F. nucleatum, B. melaninogenicus, A. viscosus, A. naeslundii, S. sanguis and pooled dental plaque all obtained from the previsouly performed experimental gingivitis. The cultures were incubated for 78 hours at 37°C in 5% CO2. 3H‐thymidine was added for the final 8 hours.Only A. viscosus was able to stimulate PBL to undergo blastogenesis during the development of experimental gingivitis. A. viscosus stimulated the PBL of 3 subjects after one week but all subjects after 2 weeks of abolished oral hygiene. The stimulation indices (SI) remained &gt;2.5 for the rest of the experimental period. Following 2 weeks of reinstituted oral hygiene, the SI reached preexperimental levels.These results suggest that A. visocus is capable of inducing a specific cellular immune response during the development of experimental gingivitis and may be important as a causative plaque constituent. Further research is indicated to study this association.

Oral hygiene and gingival health in Danish dental students and faculty

This survey attempted to determine the status of oral cleanliness and gingival health in 150 dental students and 101 faculty members in a dental school. Without advance notice, plaque deposits were scored, using the Plaque Index System, and gingival health was determined using the criteria of the Gingival Index System. The 1st-year students had the poorest hygiene and gingival health. An improvement (P less than 0.01) was noted in the 2nd-year students who were still not in clinical training but had completed a course in preventive dentistry including oral hygiene techniques. Further improvement (P less than 0.05) was found in students participating in the clinical courses (3rd and 4th years). However, some deterioration of both hygiene and gingival status occurred in the senior 5th year. Among the faculty, the best oral hygiene and gingival state were found in members of departments in which clinical work centered around patient motivation toward prevention and tooth conservation. The scores for plaque and gingivitis were worse in the departments of oral surgery, dental materials, orthodontics and the basic science departments. Almost all departments and every class showed a few individuals with very poor oral hygiene. It is suggested that regular patient contact influences the personal attitude toward oral hygiene, and that professional activity and emphasis on different aspects of the curriculum may be reflected in the attitude of health professionals toward oral health.

Lymphocyte blastogenesis to plaque antigens in human periodontal disease. ii. The relationship to clinical parameters.

This study undertook to correlate lymphocyte transformation to human dental plaque antigens with clinical estimates of periodontal disease.Forty‐eight patients with periodontal conditions ranging from normal gingivae to severe periodontitis were examined clinically. Oral cleanliness was determined by the Plaque Index System (Silness &amp; Löe 1964) and gingival health was assessed using the criteria of the Gingival Index System (Löe &amp; Silness 1963). Pocket depth and loss of periodontal attachment from the cementoenamel junction (Ramfjord 1959, Glavind &amp; Löe 1967) were also measured. Triplicate microcultures of peripheral blood lymphocytes were stimulated with four different concentrations of human plaque antigens. The uptake of 3H‐thymidine during blastogenesis was measured by liquid scintillation counting. There was no correlation between the stimulation by most of the isolated plaque antigens or pooled plaque and the periodontal conditions as determined by plaque index, gingival index, pocket depth and loss of attachment. However, there was a significant, although low, correlation between clinical parameters and the stimulation of peripheral blood lymphocytes by B. melaninogenicus and A. viscosus. Stimulation with B. melaninogenicus correlated more highly with pocket depth and loss of attachment, while stimulation with A. viscosus and A. naeslundii correlated more highly with plaque and gingivitis scores. The possible role of these organisms in the pathogenesis of periodontal disease involving cellular immunity was discussed as was the interpretation of data obtained in blastogenesis using peripheral blood lymphocytes and its relevance to the local phenomenon of delayed hypersensivity.

The influence of examination of the assessment of the intra-examiner error by using the plaque and gingival index systems.

The plaque situation on 48 surfaces in 31 children 13 years of age was assessed. A re-examination within 2 hours indicated a significant increase in the number of O Plaque Index scores. Following paired comparison of each of the 48 areas, 22 % of the surfaces were found to have changed score. Significantly more scores indicating improvement of the plaque situation were found at the second examination. A re-examination of plaque on consecutive days in a similar group of children showed no significant changes. Re-examination of the gingival conditions within 2 hours indicated a significant increase in the number of scores of 2 and this was confirmed by the paired comparison on the 48 surfaces. The findings indicate systematic errors rather than intra-examiner inconsistency.

The effect of chewing apples on dental plaque and food debris

AbstractThe aim of the present study was to assess the cleansing effect of the chewing of apples. The plaque situation in 47 children 12 years of age was assessed by the Plaque Index System. Judging from plaque incidence values, the chewing of apples had no cleansing effect on moderate amounts of plaque. A similar experiment with 57 children of the same age showed, however, that food debris was removed by chewing apples.

A new approach to the evaluation of Plaque Index scores.

The aim of the present study was to evaluate and compare methods of expressing the plaque situation recorded by the Plaque Index System (Silness and Löe 1964). Basic information based on 48 plaque recordings in each of 154 children indicated 16 ± 13% score 0, 63± 13% score 1, and 19± 14% score 2. The criteria of the Plaque Index System are at the ordinal or ranking level of measurement, whereas means and standard deviation should be performed at the interval and ratio scales of measurements, i.e. on the frequencies of the scores. Re‐examinations of the children as well as a toothbrushing experiment indicated that the frequency of score 2 adequately expressed the plaque situation. The conventional toothbrushing seemed to have no effect on the total number of score 1.

Consistency of plaque distribution in individuals without special home care instruction.

The consistency of the individual patterns of plaque distribution was evaluated over a period of time. Fifteen, first semester dental students, who had not received special home care instructions, were evaluated on five alternate days according to the criteria of the Plaque Index system. The study has shown that the pattern of plaque distribution demonstrated by each of the individuals was unique. Also, while various regions of the dentition were sometimes free from plaque and sometimes covered by plaque other areas existed in the mouths of all subjects which were consistent: either clean or covered by plaque. The clinical implications of these findings are discussed.

Optimal dosage and method of delivering chlorhexidine solutions for the inhibition of dental plaque.

The study evaluated the effect of increasing the amount of rinse solution upon the concentration of chlorhexidine needed to control plaque formation, compared the application of chlorhexidine with an oral irrigator to normal rinsing, and examined the amount of staining caused by the various dosages. Forty‐four dental students were divided into 7 groups which each used different volumes (700, 400, 200, applied with an oral irrigator and 200, 100, 50 and 20 ml used with normal rinsing). On a rotational basis, the individuals tested all concentrations (0, .01, .025, .05, .075, .1, .15 and .2 per cent) once during each 9 day test period of suspended oral hygiene. The plaque accumulation was assessed at the end of each trial period according to the criteria of the Plaque Index system. Each test period was separated by 5 days of normal oral hygiene. The study has shown that if larger volumes are used much lower concentrations of chlorhexidine are necessary, plaque inhibition in the posterior portion of the oral cavity is better with an irrigator than with normal rinsing and that staining is less with large volumes of dilute concentrations than with small volumes of stronger concentrations.