A preliminary investigation into the ultrastructure of dental calculus and associated bacteria

INTRODUCTION: Though dental calculus is generally recognised as comprising mineralised bacteria, areas of non-mineralised bacteria may be present. AIM: To investigate the ultrastructure of non-decalcified young and mature supragingival calculus and subgingival calculus, and the possible presence of internal viable bacteria. Materials and methods: Supragingival calculus was harvested from five patients, 9-10 weeks after scaling and root debridement. Five samples of mature supragingival and subgingival calculus were taken from patients presenting with adult periodontitis. Specimens were fixed and embedded for transmission electron microscopy. RESULTS: The ultrastructure of young and mature supragingival calculus was similar with various large and small crystal types. Non-mineralised channels were observed extending into the calculus, often joining extensive lacunae, both containing intact non-mineralised coccoid and rod-shaped microorganisms. Subgingival calculus possessed more uniform mineralisation without non-mineralised channels and lacunae. CONCLUSION: Supragingival calculus contains non-mineralised areas which contain bacteria and other debris. The viability of the bacteria, and their identification could not be determined in this preliminary investigation. As viable bacteria within these lacunae may provide a source of re-infection, further work needs to be done to identify the bacteria in the lacunae, and to determine their viability.     

Evaluation of selective calculus removal by a fluorescence feedback-controlled Er:YAG laser in vitro

OBJECTIVES: To evaluate the removal of subgingival calculus and dental hard tissues depending on the threshold level of a fluorescence feedback-controlled Er:YAG laser. MATERIAL AND METHODS: Twenty teeth with calculus on the root surface were treated with an Er:YAG laser. Laser settings were 140 mJ and 10 Hz. The initial fluorescence threshold level of 5 [U] was reduced at intervals of 1 [U] for every laser treatment. Areas of residual calculus (RC) were evaluated using a surface analysis software. Loss of dental hard tissues was assessed by histomorphometric analysis of undecalcified ground sections. RESULTS: Using a threshold value of 5 [U], the median amount of RC was 11% (0-78%). By lowering the threshold levels, the amount of RC decreased [level 1 [U]: 0% (0-26%)]. The laser-treated root surfaces revealed a statistically significant reduction of the cementum thickness [median: 80 microm (0-250)] compared with the non-treated opposite side [median: 90 microm (30-250)] (p<0.05). CONCLUSION: The amount of RC following laser irradiation depends on the fluorescence threshold level for a feedback-controlled Er:YAG laser. It might be suggested that this laser system may be used with a threshold level even lower than 5 [U] without removing a clinically relevant amount of root cementum.     

Factors related to the quantity of subgingival calculus in proximal root surfaces

The aim of this study was to determine the association between the quantity of subgingival calculus and the following factors: type and severity of periodontal disease, age, gender and tobacco consumption. A sample of 622 periodontal patients was studied. The radiographically detectable subgingival calculus in proximal root surfaces was recorded in periapical radiographs, considering the number of surfaces without calculus and the number of surfaces exhibiting deposits equal or greater than I mm. The association between the subgingival calculus and the factors under study was analyzed by distinct non-parametric tests. A statistically significant association was found between the absence/presence of subgingival calculus and the type and severity of periodontal disease (p<0.001), tobacco consumption (p=0.0049) and age (p<0.001). The quantity of radiographically-detectable subgingival calculus increased with increasing age and severity of the disease. However, the reverse association was found in smokers, which presented more surfaces free of calculus (p=0.0377) and less surfaces exhibiting deposits equal or greater than 1 mm. The amount of subgingival calculus decreased as the quantity of tobacco consumed increased (p=0.0129), and such differences were more significant in those smoker patients with severe periodontitis (p= 0.0065). An explanation is presented to justify these latter findings, since most literature supports that the presence of calculus is higher in smokers. According to the results of this study, more radiographically-detectable subgingival calculus in proximal root surfaces was found with increasing severity of the disease, with increasing age and with the absence of tobacco consumption.     

Tobacco smoking and supragingival dental calculus

Supragingival calculus is frequent in all ages from adolescence to old age. The influence of tobacco smoking on the occurrence and severity of supragingival calculus has received surprisingly little attention. The present investigation conducted in a population of 258 dentally aware individuals in the age range 20-69 years, was initiated to elucidate the relationship between tobacco smoking and supragingival calculus, taking into account possible confounding factors such as age, gender, oral hygiene and gingival inflammation. The calculus deposition was bilaterally assessed on the lingual surfaces of the mandibular anteriors and the vestibular surfaces of the maxillary premolars and molars. The overall prevalence of supragingival calculus was 69% ranging from 59% in age group 20-34 years to 84% in age group 50-69 years. The prevalence rates for current smokers, former smokers, and nonsmokers were 86%, 66%, and 65%. The differences between smoking groups were statistically significant (p<0.05). The influence of smoking was independent of age, plaque and gingival inflammation. In former smokers who had stopped smoking in the distant past, the occurrence and severity of supragingival calculus were very close to those in individuals who had never smoked, suggesting that the effect of smoking is reversible. The observations indicate a strong and independent association between tobacco smoking and supragingival calculus deposition. The avoidance of excess deposition of supragingival calculus, therefore, is a further argument for reducing smoking in the population.     

Tobacco smoking and subgingival dental calculus

Objective: A radiographic investigation into the relationship between tobacco smoking and subgingival dental calculus was conducted in an adult population, including 48 current smokers, 57 former smokers, and 125 non‐smokers. Material and Methods: Assessment of subgingival calculus was based on a full set of radiographs. Mesial and distal root surfaces were assessed as to presence or absence of radiopaque deposits apical to the cemento‐enamel junction. The severity of subgingival calculus deposition, labeled subgingival calculus load, was estimated from both the total number and the proportion of proximal sites affected. Results: The overall prevalence of individuals exhibiting at least one subgingival calculus positive site was 43%, ranging from 15% in age stratum 20–34 years to 72% in age stratum 50–69 years. The prevalence among current smokers, former smokers, and non‐smokers was 71%, 53%, and 28%, respectively. The differences between smoking groups were statistically significant (p<0.001). The mean subgingival calculus load of current smokers, former smokers, and non‐smokers was 3.4, 1.2, and 0.6 affected sites per person, respectively, or expressed as mean proportions, 6.2%, 2.4%, and 1.1%, respectively. The association between smoking and subgingival calculus load was statistically significant (p<0.001). The subgingival calculus load increased with increasing smoking exposure, suggesting a dose–response relationship. Conclusion: The present observations in dentally aware adults indicate a strong and independent impact of tobacco smoking on subgingival calculus deposition.     

In vitro evaluation of Er:YAG laser scaling of subgingival calculus in comparison with ultrasonic scaling

The purpose of the present study was to evaluate the effectiveness of Er:YAG laser scaling and the morphological and histological changes of the laser-scaled root surface in comparison with the effectiveness and root surface changes produced by conventional ultrasonic scaling. Fifty-three periodontally involved human extracted teeth with a band of subgingival calculus were used. The teeth were divided randomly into 2 groups for laser scaling and ultrasonic scaling. Laser irradiation was performed at an energy output of 40 mJ/pulse and 10 pulses/s under water spray, with the probe tip contacted obliquely to the root surface. Ultrasonic scaling was performed at a clinically standard power setting. The time required for scaling, the scaled area and the temperature changes were determined using both methods of treatment. The features of the scaled surfaces were examined by histological and scanning electron microscope (s.e.m.) observations. The Er:YAG laser provided subgingival calculus removal on a level equivalent to that provided by the ultrasonic scaler, without major thermal elevation. Macroscopically, the laser-treated root surface was somewhat rougher than or similar to the ultrasonically scaled root. However, the efficiency of the laser scaling was lower than that of the ultrasonic scaling. In addition, histological examination revealed a thin deeply stained zone on the lased root surface, and s.e.m. analysis revealed a characteristic microroughness on the lased surface. The laser scaling provided a level of calculus removal that was similar to that provided by the ultrasonic scaling. However, the Er:YAG laser produced superficial, structural and thermal microchanges on the root cementum.     

In vitro performance of DIAGNOdent laser fluorescence device for dental calculus detection on human tooth root surfaces

Objective

This study assessed the reproducibility of a red diode laser device, and its capability to detect dental calculus in vitro on human tooth root surfaces.

离体牙结石溶解性的研究

目的：筛选、配制几种牙结石生长抑制剂或牙结石去除剂。方法：①以离体牙结石与三种浓度的试剂或络合剂在三种温度和三种不同的时间下作用；②在超声波作用下，处理方法同①。观察两组对牙结石的溶解百分率。结果：单方，以饱和顺丁烯二酸水溶液５０℃处理１５ｍｉｎ，对离体牙结石的溶解百分率达７６．５％，复方络合剂，以柠檬酸加十六烷基三甲基溴化铵的饱和溶液５０℃处理１５ｍｉｎ，对离体牙结石的溶解百分率达４９．７％；在超声波作用下，络合剂对离体牙结石的溶解百分率提高了３０％左右。结论：从临床角度出发，络合剂对离体牙结石的溶解效果较好，超声波能提高络合剂对离体牙结石的溶解性。     

Clinical subgingival calculus detection with a smart ultrasonic device: a pilot study

Aim: We have recently tested a surface detection system based on a conventional dental ultrasonic scaler in vitro. The aim of the present study was to investigate sensitivity and the specificity of the detection device in vivo. Material and Methods: Subgingival buccal surfaces of 63 arbitrarily selected periodontally compromised teeth were scanned intra‐orally, while the supragingival positions of the insert, along with the corresponding signals of the detection system, were saved as separate files. After extraction, the surface detection results were evaluated by re‐positioning the inserts' position on the tooth in vitro and comparing the detection results with visual findings. Results: On the scanned tooth surfaces, there were 44 calculus spots, which covered 22.3% of all scanned surfaces (prevalence). The calculus‐free surface was divided into “spots” mathematically. The device correctly classified 40 calculus and 125 cementum spots, whereas four calculus and 28 cementum spots were classified incorrectly. Calculus and cementum were discriminated with a sensitivity of 91% and a specificity of 82%. The positive and negative predictive values were 0.59 and 0.97. Conclusion: The surface detection device was able to clinically differentiate cementum and calculus in vivo. Therefore, this method may support the decision of whether continued subgingival scaling could damage the cementum.     

The effectiveness of a novel optical probe in subgingival calculus detection

Abstract: Objectives: The aim of the present study was to evaluate the effectiveness of a novel optical calculus detection system under in vivo conditions. Methods: One hundred and seventy‐six tooth surfaces from 44 adult teeth that were indicated for extraction were selected for the present study. The patients were randomly assigned to one of the two experimental groups. In group A (n = 96), clinical presence or absence of subgingival calculus deposits was determined using the light‐emitting diode‐based optical probe (OP). In group B (n = 80), the subgingival deposits were first recorded with the OP followed by root surface debridement until no subgingival deposits could be detected by the device. Teeth were then extracted and examined under a stereomicroscope by two trained dentists (DENT 1, DENT 2) and a dental student. Results were compared with the measurements of the OP and direct visual control. Results: In group A, post‐extraction results revealed 89% and 90% agreement with the positive and negative OPs detection. In group B, 17% of the surfaces demonstrated even after subgingival debridement and control with the detecting device still calcified deposits in the microscopic evaluation. The highest inter‐examiner agreements were observed between DENT 1 and DENT 2. Conclusion: It was shown that the optical detection system identifies subgingival calculus with a high efficacy and therefore, may be a support for the operator to determine the endpoint of root surface instrumentation.     

Crystallography of supragingival and subgingival human dental calculus

Selected area electron diffraction of sections and individual crystal fragments of human dental calculus has demonstrated that octacalcium phosphate, hydroxyapatitc and whitlockite form the inorganic part of both supragingival and subgingival denial calculus. However, the major constituents in supragingival calculus arc platelet-shaped crystals of octacalcium phosphate and needle-shaped crystals of hydroxyapatite, while bulk crystals of whitlockite is the predominant component in subgingival calculus. The subgingival samples seemed to be better crystallized than the supragingival ones. The results obtained by the electron optical and X-ray powder investigations are in good agreement.     

An evaluation of the effects of an Nd:YAG laser on subgingival calculus, dentine and cementum

Abstract The aim of this study was to evaluate the effects of Nd:YAG laser treatment on subgingival calculus, cementum and dentine, in vitro at different power settings and durations. The study included 2 experiments. In the 1st experiment, 32 extracted teeth with calculus were divided into 8 laser treatment groups. Each tooth was treated on 2, 3 or 4 sites. In the 2nd experiment. 3 extracted cementum covered teeth and 3 extracted root planed teeth with exposed dentine were selected. 1 surface of each tooth was subjected to 8 different laser treatments. In both experiments, all specimens were assessed using scanning electron microscopy. Micrographs were taken from each treated site at X100 and X750 magnifications. An arbitrary scale (from 0 to 3) was used to score the degree of damage caused by the laser. Generally, the laser caused greater damage on calculus than either cementum or dentine. Linear regression analysis showed that higher total energy input caused a greater mean damage score on calculus (R²= 66%, p<0.001). 3-way analysis of variance showed that for calculus, the power setting, number of pulses per second and the duration of exposure contributed independently to the mean damage score in an additive way. Cementum specimens were not affected by treatment 1 (50 mJ. 10 pps, 1 s). treatment 2 (50 mJ, 10 pps, 5 s), and treatment 5 (50 mJ, 20 pps, 1 s). Dentine specimens were not affected by treatment 1 (50 mJ, 10 pps, 1 s). The results also showed that there was variability in susceptibility of different teeth and different parts of each tooth which was true for calculus, cementum and dentine.     

Detection of subgingival calculus and dentine caries by laser fluorescence

OBJECTIVES: Detection of subgingival calculus and dentine caries in the bottom of deep periodontal pockets is often difficult without visual observation. We thus examined the possibility of its detection using autofluorescence induced by laser irritation. METHODS: Autofluorescence was measured at various excitation and emission wavelength settings in five specimens each of sound dentine and enamel, subgingival calculus, and root caries. Periodontopathic model teeth with bacterial cells and blood clots were also irritated by laser to obtain autofluorescent images. RESULTS: Subgingival calculus and dentine caries showed a characteristic 700 nm emission when excited at 635 nm or a 720 nm emission when excited at 655 nm; sound dentine or enamel, however, did not. The calculus differentiation power, however, was higher with excitation at 635 nm than at 655 nm. The autofluorescent images photographed at an excitation of 633 nm provided clear calculus identification in periodontopathic model teeth when a 700 nm band-pass filter or a 700 nm high-pass filter was used. However, fluorescence intensity was masked when the calculus surface was covered by bacterial cells or blood clots. For clinical use, it would be important to remove subgingival plaque and debris from root surfaces before attempting to detect subgingival calculus and root caries with this manner. CONCLUSION: The autofluorescence method employing excitation of 633-635 nm was found to be a powerful tool for detecting subgingival calculus and root caries.     

In vitro calculus detection with a moved smart ultrasonic device

STUDY OBJECTIVE: The objective of subgingival instrumentation of periodontally diseased root surfaces is to remove the adhering microbial biofilm and calcified deposits. Recently, we have described an automated calculus detection system under static conditions. Clinically however, the tip of the system has to be moved over tooth surfaces. It was thus necessary to study the entire system in motion. METHODS: The detection device is based on a conventional dental piezoelectric ultrasonic handpiece with a conventional scaler insert. The impulse response of the mechanical oscillation system is analysed by a fuzzy logic-based computerized algorithm, which classifies various surfaces. The present study investigates dental surface recognition properties of the new system with the tip being moved over teeth surfaces in vitro. Following a training set of 7977 measurements (3960 calculus, 4017 cement) on 200 extracted teeth, 1363 measurements were conducted on 34 teeth unknown to the system. RESULTS: The surfaces cementum and calculus were correctly classified in 78% within the training set and in 81% within the set unknown, with a kappa value of 0.68. CONCLUSION: It was shown that this method of automatic recognition of tooth surfaces is able to distinguish between different tooth surfaces in vitro independently from tip movements.     

A quantitative microradiographic study of mineral content of supragingival and subgingival dental calculus

Abstract – This study was undertaken to determine the distribution and concentration of mineral in supragingival and subgingival dental calculus. Extracted incisors and premolars with attached dental calculus were used. After fixation the specimens were dehydrated and embedded in methylmethacrylate and 100-μm-thick ground sections were made. Microradiographs were produced and the mineral content in the sections was determined photometrically, using an aluminum step-wedge as a reference system. The distribution of the mineral varied considerably within the specimens and between different specimens. Supragingival calculus appeared heterogeneous and often stratified, containing areas that seemed to be non-calcified. The average mineral content was 37% by volume. By contrast subgingival calculus appeared homogeneously calcified, with an average mineral content of 58%. No differences in mineral content between surface areas and portions close to the tooth were seen. This indicates that once the calculus is formed no changes occur in the mineral content, i.e. no maturation occurs with age. Local variations in mineral content within the calculus might be explained by periodic differences in the fluid environment of the microbial plaque.     

龈上牙结石附着面和游离面晶体构型的扫描电镜观察

目的:观察牙结石附着面和游离面晶体构型的差异。方法:取新鲜牙结石,体视显微镜及扫描电镜(SEM )观察纵断面及表面结构形态的差异。结果:体视显微镜观察发现牙结石附着面和游离面存在明显的明暗分区,SEM显示牙结石断面的附着侧存在大量的细菌残迹,在菌体表面有矿物沉积,断面的游离侧晶体成规则的叶片状,牙结石表面成不规则的高度矿化区。结论:牙结石的矿化可能存在启动区和持续区的区别,矿化启动区与细菌关系密切。     

Site specific mineral composition and microstructure of human supra-gingival dental calculus

Dental calculus has been implicated in the aetiology of several periodontal conditions. Its prevention and removal are therefore desirable clinical goals. While it is known that calculus is very variable in chemical composition, crystallinity and crystallite size little is known about site specific variability within a dentition and between individuals. With this in mind, a study was undertaken to investigate the comparative site specific nature and composition of human dental supra-gingival dental calculus obtained from 66 male patients visiting for their dental check-up using fluorescent X-ray spectroscopy, X-ray diffractometry and Fourier transform infrared spectroscopy. The supra-gingival dental calculus formed on the lingual surfaces of lower anterior teeth and the buccal surfaces of upper molar teeth were classified into four types based on calcium phosphate phases present. There was significant difference in composition of the crystal phase types between lower and upper teeth (p<0.01). There was no significant difference in crystal size between dental calculus on anterior or molar teeth of all samples. The degree of crystallinity of dental calculus formed on the upper molar teeth was higher than that formed on the lower anterior teeth (p<0.01). The CO(3)(2-) contents in dental calculus formed on the lower anterior teeth were higher than on upper molar teeth (p<0.05) which might explain the difference in crystallinity. Magnesium and Si contents and Ca:P ratio on the other hand showed no significant difference between lower and upper teeth. It was concluded that the crystal phases, crystallinity and CO(3)(2-) contents of human dental supra-gingival dental calculus is related to its location in the mouth.     

Identification of calprotectin, a calcium binding leukocyte protein, in human dental calculus matrix

Calprotectin is a calcium binding protein produced by leukocytes, macrophages and epithelial cells, and its levels in several tissues increase during infections and in many inflamed areas, suggesting that it may be an indicator of inflammatory activity. Osteopontin is a prominent phosphorylated glycoprotein in bone matrix, having calcium binding capacity. Recently, it has been reported that calprotectin and osteopontin are present in urinary stones (pathological mineralized masses in the body), and that these proteins may be involved in their formation. Dental calculus formed by mineralization of dental plaque is an inflammatory factor which may contribute to periodontal disease. It contains many organic components involved in mineralization. We recently found osteopontin molecules in human dental calculus and suggested that the components of its matrix may be similar to those of urinary stones. In this study, we investigated the presence of calprotectin in human dental calculus by immunohistochemical and immunoblotting analyses using a specific antibody for calprotectin. After fixation and demineralization of dental calculi adhered to tooth roots, sections embedded in paraffin were immunoreacted with the antibody for calprotectin and positive immunostaining for calprotectin was observed. Dental calculus proteins were then extracted with EDTA and separated by electrophoresis on 15% polyacrylamide gels. By immunoblotting analysis, 3 or 4 bands were observed at 11, 14.5, 22–25, 28 or 36.5 kDa and these patterns corresponded to those of calprotectin subunits. When non-immune rabbit serum was used instead of calprotectin-specific antibody as a negative control, no immunoreactivity was observed. These findings indicate that calprotectin is associated not only with antibacterial action but also with calcium binding capacity during dental calculus formation.     

Gingival recession and its association with calculus in subjects deprived of prophylactic dental care

Abstract. This paper describes the prevalence and severity of gingival recession in Tanzanian adults covering the age range from 20 to 64 years. In addition, it attempts to assess the relationship between the degree of gingival recession and the presence and amount of calculus. In the 20–34 years age group recession occurred in ≥32% of the buccal. ≥25% of the lingual, and ≥13% of the approximal surfaces. These %s increased to ≥64%, ≥52%, and ≥48%, respectively, in the 45–64 years age group. In the 20 34 years age group, lingual surfaces of mandibular incisors and canines followed by buccal surfaces of these teeth were the sites most severely affected with gingival recession. With increasing age, all sites became gradually more severely affected, particularly the buccal and lingual surfaces of the maxillary first molar. The lingual surfaces of mandibular incisors exhibited on an average 1.3 mm. 2.4 mm and 3.2 mm recession in the 20–34 years, 35–44 years and 45–64 years age group, respectively. Most of the correlation coefficients between gingival recession and calculus at the individual tooth surface in three age groups were statistically significant. The highest correlation coefficients (0.50–0.67) were found in the youngest (20–34 years) age group al the lingual surfaces of the mandibular incisors, canine and first premolar and al the buccal surfaces of the mandibular incisors. Based on these findings, the working hypothesis is advanced that longstanding calculus is an important determinant in the onset of gingival recession at sites exhibiting pronounced recession at a young age in populations deprived of prophylactic dental care.     

The effects of subgingival calculus on the clinical outcomes of locally-delivered controlled-release doxycycline compared to scaling and root planing

BACKGROUND, AIM: The effect of subgingival calculus on the clinical outcomes of the local delivery of antimicrobials is unknown. This study examines the clinical outcomes of treatment with locally delivered controlled-release doxycycline (DH) or scaling and root planing (SRP) in subsets of adult periodontitis patients with known baseline levels of subgingival calculus. METHODS: The data examined were obtained from 393 patients who participated in 2 multi-center trials. All patients had baseline subgingival calculus levels assessed and were then treated at baseline and month 4 with either DH or SRP. Clinical attachment levels (CAL), pocket depth (PD) and bleeding on probing (BOP) were assessed at baseline and months 1, 2, 4, 5, 6, 8 and 9. RESULTS: Treatment with either DH or SRP resulted in significant statistical and clinical improvements in CAL, PD and BOP. These clinical outcomes were equivalent regardless of the extent of subgingival calculus present at baseline. CONCLUSIONS: The results indicate that the primary clinical effects of these therapies are the result of a disruption and reduction of the subgingival plaque and not the effect of the removal of subgingival calculus and contaminated cementum.