Calculus revisited. A review

Fluoride profiles in dental calculus from Japanese, Chinese and British residents

Whether the fluoride concentrations and profiles differ in human dental calculus obtained from different countries was investigated. A total of 203 dental calculus deposits on 203 permanent teeth from residents (mean age, 52.1 years) of Nagoya (Japan), Shanghai (China), Leeds (Great Britain) and the Wuhan mountainous area (China, fluoridated area) were analysed. An abrasive microsampling procedure was used to examine fluoride distribution. There were five types of fluoride profiles in dental calculus in each area/country (designated types L, J, U, T, W). In supragingival calculus, type L (highest in the outermost layers) and type J (highest in the innermost layers) both had significantly higher values than type U (high in the surface and innermost layers) but were relatively identical. In subgingival calculus, type W (high in the outermost, mid and innermost layers) was characteristics. Calculus from the Wuhan mountainous area (fluoridated) had the highest fluoride concentration, followed by Leeds (non-fluoridated), and Nagoya and Shanghai (non-fluoridated) calculus had the lowest. Fluoride concentrations in supragingival calculus were higher in teeth extracted because of periodontal diseases than dental caries. It is concluded that fluoride concentrations and distribution in dental calculus differ from country to country, probably due to different fluoride environments.

Dental calculus: recent insights into occurrence, formation, prevention, removal and oral health effects of supragingival and subgingival deposits

Dental calculus, both supra- and subgingival occurs in the majority of adults worldwide. Dental calculus is calcified dental plaque, composed primarily of calcium phosphate mineral salts deposited between and within remnants of formerly viable microorganisms. A viable dental plaque covers mineralized calculus deposits. Levels of calculus and location of formation are population specific and are affected by oral hygiene habits, access to professional care, diet, age, ethnic origin, time since last dental cleaning, systemic disease and the use of prescription medications. In populations that practice regular oral hygiene and with access to regular professional care, supragingival dental calculus formation is restricted to tooth surfaces adjacent to the salivary ducts. Levels of supragingival calculus in these populations is minor and the calculus has little if any impact on oral-health. Subgingival calculus formation in these populations occurs coincident with periodontal disease (although the calculus itself appears to have little impact on attachment loss), the latter being correlated with dental plaque. In populations that do not practice regular hygiene and that do not have access to professional care, supragingival calculus occurs throughout the dentition and the extent of calculus formation can be extreme. In these populations, supragingival calculus is associated with the promotion of gingival recession. Subgingival calculus, in "low hygiene" populations, is extensive and is directly correlated with enhanced periodontal attachment loss. Despite extensive research, a complete understanding of the etiologic significance of subgingival calculus to periodontal disease remains elusive, due to inability to clearly differentiate effects of calculus versus "plaque on calculus". As a result, we are not entirely sure whether subgingival calculus is the cause or result of periodontal inflammation. Research suggests that subgingival calculus, at a minimum, may expand the radius of plaque induced periodontal injury. Removal of subgingival plaque and calculus remains the cornerstone of periodontal therapy. Calculus formation is the result of petrification of dental plaque biofilm, with mineral ions provided by bathing saliva or crevicular fluids. Supragingival calculus formation can be controlled by chemical mineralization inhibitors, applied in toothpastes or mouthrinses. These agents act to delay plaque calcification, keeping deposits in an amorphous non-hardened state to facilitate removal with regular hygiene. Clinical efficacy for these agents is typically assessed as the reduction in tartar area coverage on the teeth between dental cleaning. Research shows that topically applied mineralization inhibitors can also influence adhesion and hardness of calculus deposits on the tooth surface, facilitating removal. Future research in calculus may include the development of improved supragingival tartar control formulations, the development of treatments for the prevention of subgingival calculus formation, the development of improved methods for root detoxification and debridement and the development and application of sensitive diagnostic methods to assess subgingival debridement efficacy.

Human supragingival in vivo calculus formation in relation to saturation of saliva with respect to calcium phosphates

The aim was to establish if there is a correlation between the rate of formation of supragingival calculus and the degree of supersaturation of saliva with respect to apatite, brushite and other calcium phosphates. The rate of calculus formation was estimated by measuring the calculus formed on lingual surfaces of the lower incisors in 15 individuals during 30 days. Submandibular saliva stimulated with citric acid and resting whole saliva, alter pH determination and ultrafiltration to remove protein was analysed for calcium, phosphate, sodium, potassium and carbonate. The degree of saturation with respect to calcium phosphates was calculated using a computer program. The rate of calculus formation among the 15 participants ranged widely, from a score of 0.5 to a high of 15. A close correlation (r = 0.91) between salivary pH and degree of supersaturation was found A weak correlation between calcium and calculus formation was also found. But neither for unstimulated nor stimulated saliva was a significant relation between supersaturation with respect to any of the calcium phosphates and the rate of calculus formation observed. Therefore, taking into consideration the background of the wide range of rates of calculus formation and of degrees of supersaturation, it was concluded that relation between them is unlikely, and the use of degree of saturation as a diagnostic tool seems unreliable.

Periodontal pocket treatment in beagle dogs using subgingival doxycycline from a biodegradable system. I. Initial clinical responses

The present study evaluated the clinical response of periodontal pockets in beagle dogs after treatment with a biodegradable delivery system containing 10% doxycycline hyclate (ABDS-D). Eight adult, female beagle dogs had generalized, severe periodontitis with plaque and calculus-laden pockets. In each animal, 3 teeth with multiple pocket sites > or = 4 mm (mean depth = 6.0 mm) associated with attachment loss (mean = 5.4 mm) and which bled on probing (mean score = 2.5) were treated with a single application of either ABDS-D (experimental group) or the delivery system alone without the doxycycline (control group). Residual polymer was removed at day 7. Bioassay of doxycycline in gingival crevicular fluid associated with presence of ABDS-D gave mean levels of bioactivity of approximately 250 micrograms/ml. Levels of bioactive doxycycline were detected for approximately 7 days after ABDS-D removal. Periodontal maintenance consisted of thrice-weekly toothbrushing the treated sites. Clinical responses were evaluated at 2 weeks, and at bi-weekly intervals thereafter for 4 months. Analyses of the data from the control group showed that there was only slight clinical improvement. In contrast, in the experimental group, bleeding on probing and probing depths were significantly reduced from baseline at all post-treatment time points. At 1 month, mean probing depth reduction was 2.4 mm and this was maintained at 4 months (mean reduction = 2.5 mm). These probing depth reductions occurred primarily through gain of clinical attachment which was 2.0 mm at 4 months. Bleeding had been virtually eliminated (mean = 0.2). It was concluded that, for the beagle dogs with severely infected periodontal pockets in this study, treatment with subgingival doxycycline using the delivery system resulted in substantial improvement in periodontal health.

Effects of a rhubarb (Rhei rhizoma) solution and its fractions on the formation of calcium phosphate precipitates

Inhibitory effects of a rhubarb (Rhei rhizoma) solution and its fractions on the formation of calcium phosphate precipitates were studied. The rhubarb solution inhibited both the amorphous calcium phosphate (ACP) formation and the rate of hydroxyapatite (HAP) transformation, and extended the induction time. When the solution was fractionated using membrane filters, a filtrate with the molecular weight between 3 and 10 kDa (with 2/3 recovery of polyphenols) was found to be responsible for both the ACP formation and the extension of the induction time. Another filtrate with the molecular weight below 3 kDa (with 1/3 recovery of polyphenols) may be responsible for the inhibition of both the ACP formation and the rate of HAP transformation, and the extension of the induction time. When the extract of rhubarb was fractionated using a Sephadex LH-20 column chromatography, fraction IV greatly inhibited the formation of calcium phosphate precipitates, while fractions I, II and III slightly inhibited that reaction. Our finding suggests that fraction IV may contain useful substance(s) for the prevention of oral calcium phosphate precipitation (calculus formation). However, strong calcium chelating properties would limit the concentration that could be safely employed.

Calculus update: prevalence, pathogenicity and prevention

Does reduction of supragingival calculus provide only a cosmetic effect, or does it benefit oral health as well? The author discusses the causes and effects of calculus development and reviews methods of calculus control.

Site progression of loss of attachment over 5 years in 14- to 19-year-old adolescents

The aims of this study were (1) to monitor the progression and patterns of progression of loss of attachment > or = 1 mm on a site basis over a 5-year period in adolescents, and (2) to relate the presence of oral deposits and inflammation to the subsequent development and progression of loss of attachment on a site basis. 167 subjects were examined at ages 14, 16 and 19 years. Loss of attachment > or = 1 mm, plaque, subgingival calculus, gingival bleeding and gingival colour change were assessed on the mesio-buccal sites of the 1st molars, 1st premolars and central incisors. Each site was treated separately in the analysis to avoid the problem of within-subject site dependence. Sites were classed as progressing, non-progressing or fluctuating according to the probing attachment level measurements at each of the 3 examinations. During the 5 years of this study, a total of 542 sites in 128 subjects progressed; 1136 sites in 162 subjects did not progress; 43 sites in 30 subjects had fluctuating attachment level measurements. Sites which subsequently progressed had significantly more plaque, subgingival calculus and gingival inflammation than non-progressing sites at the baseline examination and throughout the study (p < 0.001). Between 55-57% of the maxillary 1st molars and 46-49% of the mandibular incisors progressed. In contrast, there was no progression of loss of attachment on over 80% of the maxillary central incisors and mandibular 1st premolars.

Relationship of gingival calculus and bleeding on probing in CPITN code 2 sextants

The aims of this study were twofold: firstly, to evaluate the relationship of supra- or subgingival calculus and bleeding on probing (BOP) in sextants coded 2 in the Community Periodontal Index of Treatment Needs (CPITN); and secondly, to compare the differences in four investigations in Taiwan, Hong Kong, Japan and Norway. In a national survey, a total of 2658 Chinese dentate adults were examined by using modified CPITN in the Taiwan area from 1985 to 1987. Sextants given Code 2 were divided into four subclassifications: supragingival calculus with bleeding (I+), supragingival calculus without bleeding (I-), subgingival calculus with bleeding (II+) and subgingival calculus without bleeding (II-). The results showed that of the 9394 sextants given Code 2, the highest percentage (70%) were characterized by the presence of subgingival calculus with bleeding and the lowest percentage (4%) by supragingival calculus with bleeding. The ratio of sextants coded 2 with only supragingival calculus versus subgingival was 1:6.2. The bleeding to nonbleeding ratio of sextants coded 2 in this study was similar to the Hong Kong study. However, differences among Taiwan, Japan and Norway were found. The results indicated that sextants with subgingival calculus had a higher tendency to BOP, with a ratio of 4:1. Those with supragingival calculus had a ratio of 3:7. We conclude therefore, that it is essential to scale teeth to remove subgingival calculus for determination of the necessity of periodontal treatment.

Control of supragingival calculus. Scaling and polishing and anticalculus toothpastes: an opinion

The removal of supragingival calculus by scaling and polishing of the teeth is only one aspect of a dental prophylaxis. However in many countries, a large number of individuals only require and receive, at regular intervals, a supragingival scale and polish. The association of supragingival calculus to gingival and periodontal disease is unclear, however, it is logical to assume a plaque retention role. Moreover, for the individual, supragingival calculus may pose cosmetic problems. Regular calculus removal is both time consuming and exacting for dental professionals and has important financial implications to patients and/or health schemes. The benefits of regular supragingival calculus removal are not established, yet potential detrimental effects for the patient are known, and certain groups are susceptible to systemic disease consequent on scaling and polishing of the teeth. The oral hygiene habits of most individuals appear insufficient to prevent the reformation of supragingival calculus once removed and for this reason chemical inhibition is an attractive proposition. Most success to date has been with agents which inhibit crystal growth, notably pyrophosphates, and toothpaste products are available containing such agents. Clinical studies support efficacy for some products and indicate that the magnitude of calculus inhibition would reduce the need for or frequency of scaling and polishing of teeth in a proportion of individuals. Anticalculus toothpastes would appear to be proven worthy of recommendation for those individuals in whom supragingival calculus formation is a problem.

Effectiveness of a calculus scaling gel

This study evaluated the effect of a calculus scaling gel (SofScale) on time and ease of the scaling procedure in a double-blind, split-mouth clinical study of 32 subjects. The Volpe-Manhold calculus index was used to quantify the distribution and amount of calculus deposition on the lingual aspect of the mandibular 6 anterior teeth at baseline. The gel was applied directly to the calculus and subgingivally to the area to be scaled. Pre- and post-treatment gingival and stain indices were taken. Operator and subject questionnaires were completed immediately after treatment to determine ease of the scaling procedure. Results were analyzed with paired t-tests. The time difference in scaling between the product and placebo side was not significant. This study found that SofScale is safe to gingival tissues and does not promote tooth sensitivity. However, this study did not find significant differences in scaling time between product and placebo when using a 2-minute gel contact time.

Assessment of risk for periodontal disease. I. Risk indicators for attachment loss

Specific risk indicators associated with either susceptibility or resistance to severe forms of periodontal disease were evaluated in a cross-section of 1,426 subjects, 25 to 74 years of age, mostly metropolitan dwellers, residing in Erie County, New York, and surrounding areas. The study sample exhibited a wide range of periodontal disease experience defined by different levels of attachment loss. Therefore, it was possible to accurately assess associations between the extent of periodontal disease and patient characteristics including age, smoking, systemic diseases, exposure to occupational hazards, and subgingival microbial flora. Age was the factor most strongly associated with attachment loss, with odds ratios for subjects 35 to 44 years old ranging from 1.72 (95% CI: 1.18 to 2.49) to 9.01 (5.86 to 13.89) for subjects 65 to 74 years old. Diabetes mellitus was the only systemic disease positively associated with attachment loss with an odds ratio of 2.32 (95% CI: 1.17-4.60). Smoking had relative risks ranging from 2.05 (95% CI: 1.47-2.87) for light smokers increasing to 4.75 (95% CI: 3.28-6.91) for heavy smokers. The presence of two bacteria, Porphyromonas gingivalis and Bacteroides forsythus, in the subgingival flora represented risks of 1.59 (95% CI: 1.11-2.25) and 2.45 (95% CI: 1.87-3.24), respectively. Our results show that age, smoking, diabetes mellitus, and the presence of subgingival P. gingivalis and B. forsythus are risk indicators for attachment loss. These associations remain valid after controlling for gender, socioeconomic status, income, education, and oral hygiene status expressed in terms of supragingival plaque accumulation and subgingival calculus. Longitudinal, intervention, and etiology-focused studies will establish whether these indicators are true risk factors.

The periodontally-involved root surface

Recent years have seen much research on the periodontally-involved root surface. Many of these studies have produced results which suggest that plaque contaminants of the root surface are only superficially placed, and capable of being removed by gentle means. Further research has attested to the difficulties in rendering periodontally-involved root surfaces free of calculus deposits by instrumentation, yet clinical studies show that periodontal disease can be managed by root planing. It is concluded that root surface debridement is best assessed on the basis of the healing response and that it should aim to disrupt plaque on and remove plaque from the periodontally-involved root surface rather than to remove part of the root surface itself.

Inhibition of the formation of oral calcium phosphate precipitates: beneficial effects of Chinese traditional (kampo) medicines

Screening tests on the formation of calcium phosphate precipitates using 23 different kinds of Kampo medicines (Chinese traditional medicines) were carried out, at concentrations where the effects of chelation are not significant. Four of them, Hochu-ekki-to (TJ-41), Kyuki-kyogai-to (TJ-77), Oren-to (TJ-120) and Inchin-ko-to (TJ-135) showed an inhibitory effect on the formation of amorphous calcium phosphate (ACP). The inhibitory effect on the induction time and the rate of transformation to hydroxyapatite (HAP) varied greatly among the 23 Kampo medicines. We classified them according to their effects on increasing the induction time and/or decreasing the rate of HAP transformation. Ethane-1-hydroxy-1, 1-diphosphonate (EHDP) was used as the standard. This compound is a common toothpaste additive which decreases dental calculus formation. Two of the 23 Kampo medicines showed little or no inhibition either on the induction time or on the rate of HAP transformation. Twelve of them reduced the rate of HAP transformation by 20-40% and with 1.9- to 4.0-fold increases in the induction time. The remaining nine showed even greater activity. Keishi-ninjin-to (TJ-82), Dai-kenchu-to (TJ-100), Toki-to (TJ-102), Rikko-san (TJ-110) and San'o-shashin-to (TJ-113) showed the same inhibitory effect as EHDP. Shigyaku-san (TJ-35;5.2-fold), Dai-kanzo-to (TJ-84;4.9-fold), Oren-gedoku-to (TJ-15;12.7-fold) and Inchin-ko-to (TJ-135;9.5-fold) had a greater effect on the increase of induction time than EHDP and reduced the rate of HAP transformation by 50-60%. These results suggest that these nine kinds of Kampo medicines may have potential as anticalculus agents in toothpastes and mouthwashes.

Calculus removal from multirooted teeth with and without surgical access. (I). Efficacy on external and furcation surfaces in relation to probing depth

The purpose of this study was to evaluate the efficacy of the calculus removal from multirooted teeth after closed root planing, open root planing and use of a rotary diamond for the furcation area. The effect of pocket depth on the effectiveness of calculus removal was also examined. 30 first and second lower molars scheduled for extraction, with a calculus index > or = 2 and a degree II or III furcation involvement, were divided into 3 groups: 10 molars were scaled and root planed using a closed approach; 10 molars were scaled and root planed using an open approach; 10 molars were scaled and root planed with an open approach and rotary diamond was used for removal of deposits in the furcation area. After extraction, the teeth were assessed in a stereomicroscope and the % of residual calculus was calculated on external and furcation surfaces. The % of residual calculus on the external surfaces was significantly higher after closed than open root planing (p = 0.002). Pocket depth affected the effectiveness of scaling and root planing, with more residual calculus observed for depths > or = 7 mm for both groups. Differences between the 3 groups in the % of residual calculus on furcation surfaces were statistically significant (p < 0.0001 and p < 0.0005). The most effective method was the combination of open root planing and rotary diamond. More calculus was observed in all groups for pocket depths > or = 7 mm but the difference was significant only in the closed group (p = 0.006).(ABSTRACT TRUNCATED AT 250 WORDS)

The hard tissue lesion revisited

Recent research indicates that the thorough removal of calculus is still a critical step in the treatment of periodontal disease. Surgical access facilitates this in deep pockets. Repair is mediated by a long junctional epithelium as microscopically total calculus removal is rarely achieved. In intrabony defects the apical portion of the root surface which has not attracted deposits of calculus has the potential for connective tissue reattachment and regeneration if care is taken to preserve collagen fibres still attached to the root.

Assessment of ultrasonic debridement of calculus-associated periodontally-involved root surfaces by the limulus amoebocyte lysate assay. An in vitro study

This investigation assessed the effectiveness of an in vitro ultrasonic debridement regime on periodontally involved teeth with visually-detectable calculus deposits, using the LAL assay for lipopolysaccharides (LPS) as a marker of bacterial products. 34 single rooted teeth with extensive amounts of calcified accretions were selected, of which 10 served as uninstrumented controls for the estimation of existing LPS levels. The periodontally involved roots of the 24 experimental teeth were debrided with a Cavitron TF-10 tip for a limited time using light pressure and overlapping strokes which ensured complete surface instrumentation without reference to the presence of calculus. Marked reductions in root surface area coverage by calculus were nevertheless achieved as assessed planimetrically from photographic records of the teeth before and after debridement. The root surfaces of each tooth were then stripped away and the harvested material subjected to 'Westphal' extraction and LAL assay for LPS. The resulting LPS yields from the experimental teeth ranged from less than 0.08 to 22.387 ng compared to 1,900 to 29,200 ng from the uninstrumented controls. The extremely small residual LPS yields from the experimental teeth not only confirm the efficacy of ultrasonic debridement but, when coupled with the lack of a relationship with the widely varying amounts of the remaining calculus, support the contention that bacterial plaque rather than calculus has the greater pathogenic potential. These results reinforce the growing impression of the superficial location of bacterial toxic products associated with periodontally involved root surfaces.

The natural history and clinical course of calculus formation in man

This paper describes levels and progression of supra- and subgingival calculus undisturbed by active professional intervention or home care between 1970 and 1985 in Sri Lanka, or when removed at regular intervals between 1969 and 1988 in Norway. In the Sri Lankan tea laborers, both supra- and subgingival calculus formation started before age 14 years. At 40 years of age, all participants and almost all teeth and tooth surfaces had calculus. Tea laborers who both smoked tobacco and chewed betel had significantly higher calculus scores than those who only had one of these habits, and those who neither chewed nor smoked had the lowest calculus scores. Teeth with calculus showed a significantly higher rate of loss of attachment than teeth that remained calculus free. For the Norwegians who had enjoyed regular dental care throughout their lives, supragingival calculus did not increase in frequency from adolescence to the forties. Approximately 70% of the interproximal surfaces were calculus free after 40-50 years of age. Subgingival calculus scores, although low, showed some increase with longer times of exposure. On average, each person had 0.4 interproximal surfaces with subgingival calculus as they approached 50 years of age. In this Norwegian population, subgingival calculus had no impact on loss of attachment.

Anticalculus effect of a dentifrice containing 0.5% zinc citrate trihydrate

A doubleblind 3-month anticalculus clinical study was conducted to determine the magnitude of the antitartar effect to be derived from use of a 0.5% zinc citrate dentifrice. From a population of 1600 subjects exhibiting calculus, 1210 subjects (age 18 and over) were selected and received a dental prophylaxis. The subjects were initially stratified on the basis of calculus score, age, and sex, then allocated randomly to a 3-month usage period of one of two treatment groups. These were a dentifrice containing 0.5% zinc citrate or a control dentifrice without zinc citrate. Calculus was assessed using the Volpe-Manhold Index. Oral soft tissue status was assessed throughout the course of the study. At the conclusion of the study 964 subjects had completed the trial: 486 using the zinc citrate dentifrice and 478 using the control. The results showed that the mean calculus scores in the group using the dentifrice containing zinc citrate were 13.7% lower than those of the group using the control dentifrice. This finding was statistically significant (P less than 0.05). No adverse effects related to the use of either dentifrice were observed.

Why pick on teeth?

In the evolution of oral hygiene practices, the toothpick is the progenitor device. Although modern variations are used interdentally, with the current emphasis on plaque control rather than gingival massage and stimulation, the toothpick has been largely superseded by floss, interproximal brushes, and other supplementary aids. The natural hard bristle toothbrush and vigorous scrub brushing popular a generation ago have been replaced by soft bristle nylon brushes and gentler, more defined brushing procedures for plaque removal in the crevicular areas. Quantitative studies support the superiority of the current techniques in maintaining periodontal health with less trauma to the oral tissues.

Some predictors of radiographic alveolar bone height reduction over 6 years

The present study was undertaken to 1) develop a model to predict the proportion of sites with alveolar bone height reduction over 6 years by means of a few factors, 2) build a second model to predict the initial values of the dependent variable, and 3) describe the relationship between initial bone loss and the bone loss over 6 yr with age. 142 subjects (18-67 yr) were examined radiographically at baseline and 6 yr later using a standardized method. For each subject, the proportion of sites depicting significant alveolar bone height reduction during the study was assessed. Explanatory variables were: presence of initial bone loss, local plaque retaining factors, age, sex, number of missing teeth at baseline and rheumatoid arthritis. Employing multiple regression analysis, the combined effect of initial bone loss, plaque retaining factors, age and rheumatoid arthritis provided the best model suited to predict the proportion of sites undergoing bone loss over time. However, age, plaque retaining factors and number of missing teeth were the best predictors of initial bone loss. A logistic regression model was then used to study the significance of these predictors at the site level. This model indicated that alveolar bone loss over time at a given site is related mainly to presence of local factors and initial bone loss at that site as compared to the effect of other sites with local factors and initial bone loss in the subject. Age demonstrated a linear relationship with initial bone loss and a curvilinear relationship to periodontal disease progression.(ABSTRACT TRUNCATED AT 250 WORDS)

Measurement of dietary and dentifrice effects upon calculus accumulation rates in the domestic ferret

Most animal models for the study of calculus accumulation and control currently use rodents or dogs. In an effort to overcome limitations inherent in the use of these species, we investigated calculus formation in domestic ferrets, a species used by King et al. in the 1940's and 1950's. Ferrets are much smaller than dogs, and, unlike rodents, can be scored while alive. In this study, we examined the kinetics of calculus formation in female ferrets fed with moist canned cat food--either plain or supplemented with sucrose--and two combinations of mineral salts. An additional group given supplemented cat food was treated twice daily with regular Crest toothpaste. Animals were sedated with a 1:1 mixture of ketamine and xylazine solutions and given a mechanical prophylaxis prior to the trial period, then scored for area and extent of calculus accumulation at two, four, six, and eight weeks thereafter. The data showed that the mineral-supplemented groups accumulated calculus at a significantly faster rate than the unsupplemented or dentifrice-treated groups, but the differences were no longer significant at eight weeks. This demonstrated that the ferret is a suitable model for the study of calculus, that dietary mineral content influenced calculogenesis, and that the application of regular dentifrice initially slowed, but did not prevent, calculus accumulation.

Critical evaluation of the composition and use of topical fluorides, with emphasis on the role of calcium fluoride in caries inhibition

There is evidence that a major part of the fluoride which is retained on teeth during topical application is calcium fluoride or calcium fluoride-like, and that this material is relatively stable in the mouth. This is due to surface adsorption of phosphate (HPO4(2-)) ions onto the calcium fluoride surface. Calcium fluoride releases fluoride during caries challenges due to reduced concentration of HPO4(2-) at acid pH. Normally, the fluoride released from calcium fluoride during caries challenges is subsequently built into hydroxyfluorapatite through dissolution/re-precipitation reactions. It appears likely that the formation of calcium fluoride from topical application agents should be increased and not reduced, as believed in the past. Increased deposition of calcium fluoride can be achieved with increased reaction time between fluoride and enamel, reduced pH of the solution, increased concentration, or pre-treatment with calcium. A reduction in pH of the agents is probably the most practical approach to increase the deposition of calcium fluoride during topical application, and clinical data support this contention. Calcium fluorides with various dissolution rates are formed during different procedures of topical application with fluoride, presumably due to incorporation of phosphate into the calcium fluoride crystals.

Public health implications of recent research in periodontal diseases

Knowledge of the epidemiology, natural history, and bacterial etiology of the periodontal diseases has advanced considerably as a result of research conducted through the 1980s. Prevention and control of these conditions, however, remains mechanical, cumbersome, and often impractical, based as it is on bacterially nonspecific plaque removal for an indeterminate period. This research has not yet changed the content of public health programs, but it does affect the way the programs are applied. Because sever, generalized disease seems to be less prevalent than previously thought, the need of regular, routine professional care for everybody is questioned. Professional care in a public health context is likely to be more efficient when targeted toward those with severe disease. Dental health education for personal oral hygiene is still supported by scientific studies, though a targeted approach and careful assessment of educational content is needed. Until predictive screening methods for identifying susceptible individuals are developed, selection of priority groups for education and treatment should be guided by epidemiologic data.

Severe localized destruction of the periodontium secondary to subgingival displacement of an elastic band. Report of a case

A seven-year-old male with localized severe periodontal destruction at the maxillary central incisior region presented for treatment. There was a history of acute trauma, but local factors were inconsistent with the clinical picture. Initial treatment consisting of palliative nonsurgical debridement coupled with systemic tetracycline resulted in a more chronic lesion with progressive bone loss. Surgical entry revealed an elastic band close to the apices of the central incisors. Removal of the etiologic agent has resulted in increased radiographic bone density and decreased probing depths. Periodontal lesions induced by elastic bands are difficult to diagnose but have several features in common that may aid in rapid diagnosis and treatment.

Rhinolithiasis: a review

A rhinolith is an object that has become lodged in the nose and has slowly calcified. It is seen on dental radiographs as a radiopaque object in the nasal fossa and may be confused with several pathologic entities that call for more invasive surgical procedures. A history of unilateral nasal stuffiness, obstruction, and discharge is common but not always present. Two clinically diverse cases are presented.

Effects of subgingival irrigation on periodontal status

Periodontal diseases are localized, plaque-related infections. Often, clinical signs of inflammation are not eradicated by supragingival plaque control, dictating that subgingival microbial populations must be reduced. Confirmation that it is possible to deliver medicaments to the base of deep pockets stimulated numerous investigations. This report evaluates the role of site-specific pharmacotherapy to enhance periodontal status.