根管峡区的定位、发生率及临床意义

根管峡区(root canal isthmus,RCI)是位于同一牙根内、根管之间含有牙髓或牙髓衍生组织,呈现为带状狭窄的连接或含有交通支及横向吻合的解剖学结构,它常存在于含有两个根管的牙根中,解剖结构复杂.不同牙位的RCI发生率不尽相同,发生率最高的部位是下颌第一磨牙近中根和上颌第一磨牙近中颊根.RCI的存在增加了根...     

Epidemiology of root surface caries in patients treated for periodontal diseases

The prevalence of root surface caries was estimated in 83 patients surgically treated for periodontal disease and some relating factors were analyzed. The overall root caries index (RCI) was 6.28%. Anterior teeth in the mandible were significantly less affected than other groups of teeth. Root surfaces, divided into subgroups according to surgical treatment and length of exposure, showed no significant differences in RCI. No correlation was found between DFS-index and RCI. RCI increased with age. Concomitantly in older people more time had elapsed between the periodontal treatment and the present clinical examination. Salivary S. mutans counts and a combination of higher salivary S. mutans and lactobacilli counts were good indicators for the presence of root surface caries.     

Impact of treatment provision on the epidemiological recording of root caries

The estimation of root caries prevalence and the identification of risk factors for decay depend upon the successful identification of carious lesions in epidemiological studies. Root surface restorations can either be placed to manage decay or cervical wear/sensitivity. The handling of data for restorations during epidemiological surveys is critical to the accurate assessment of caries prevalence. The objective of this study was to determine the relative frequency of dentists' placing root surface restorations according to their reason for placement. Data for 696 restorations were recorded from 35 dentists. Forty-five % of restorations were placed because of decay compared with 55% for cervical wear/sensitivity. There were no significant differences in proportion of placement of restoration with age of the patient or between regular and irregular attenders of different ages. Using these data a correction factor was developed for inclusion in the Root Caries Index (RCI) to make allowance for the proportion of restorations placed because of wear/sensitivity. When this correction factor was introduced into an existing data-set for root caries, the RCI was reduced for all groups. This reduction was greatest in regular attenders. When these data were analysed without making allowance for treatment effects, there was a significant difference in RCI between regular and irregular attenders. When the correction factor was applied to these data, this difference was eliminated.     

The use of mineral trioxide aggregate in endodontics

Mineral trioxide aggregate (MTA), composed mainly of tricalcic silicate, tricalcic alluminate, bismuth oxide, is a particular endodontic cement. It is made of hydrophilic fine particles that harden in the presence of dampness or blood. It is biocompatible, radiopaque and it is harder to infiltrate, compared to classic materials for root filling such as amalgam, cements, Super-EBA, and IRM. and SEM studies of sections and copies in resin of root neoapices filled with amalgam, IRM, Super-EBA and MTA, as well as tests of microinfiltration have shown that MTA has excellent sealing capacities. It requires a working time of about 5 min and a hardening time that varies from 2 h and 45 min to 4 h according to the density of the air entrapped during mixing and the dampness of the receiving site. The long hardening time reduces internal tensions and the incidence of marginal infiltration, but it forces to definitively fill the tooth in the following sitting, with an interval of at least 3 days from the MTA application. Clinical experience shows how MTA is a material of choice in cases not only of endodontic surgery, apicectomy and retrograde filling but also in the sealing filling of perforations of the pulp chamber and of the root, stripping, internal reabsorptions, readaptations, lacerations, and apical transports. It has been used with success also in direct cappings and in apexifications instead of calcium hydroxide, leading to quicker therapies and more predictable RESULTS: The authors outline the operative phases of the different treatments proposed, make a survey of the most important studies published so far and hope that a new sealing cement with more reduced hardening times will soon be available.     

Root caries prevalence in a group of Brazilian adult dental patients

The aim of this study was to measure the caries prevalence in the root surface in a group of Brazilian adults. The prevalence and their intraoral distribution of caries lesions of root surface were assessed in dental patients ranging in age from 35 to 44 and from 50 to 59 years of age of both sexes (n=360). A total of 98.9% had root surfaces with gingival recession and 78.1% had at least one root caries lesion. The prevalence of the disease was analyzed using the Root Caries Index (RCI). The average value was greater for women (18.6%) than for men (13.4%) (p<0.01) and similar in both age groups (p>0.01). The maxillary canines and first premolars and the mandibular molars presented the greatest RCI values. The RCI was greater in the proximal surface of the maxilla and buccal surface of the mandible. We conclude that caries of the root surface are present in the Brazilian population and deserve attention concerning their actual role in the epidemiology of principal oral diseases of the adult population.     

Root caries patterns and risk factors of middle-aged and elderly people in China

Abstract –  The objectives of this study were to describe root caries patterns of Chinese adults and to analyze the effect of selected demographic and socioeconomic factors on these patterns. A total sample of 1080 residents aged 35–44-years-old and 1080 residents aged 65–74-years-old from three urban and three rural survey sites in Hubei Province participated in both an oral health interview and a clinical oral health examination. Root surface caries prevalence rates were 13.1% in the middle-aged group and 43.9% in the elderly group. The mean number of teeth affected by caries in the middle-aged group was reported at 0.21 and 1.0 in the elderly group. Mean Root Caries Index (RCI) scores of the middle-aged were reported at 6.29 and elderly subjects were reported at 11.95. Elderly people living in rural areas reported a higher RCI score (13.24) than those living in urban areas (10.70). A significantly higher frequency of root surface caries was observed in elderly participants ( P  < 0.001, OR = 3.80) and ethnic minorities ( P  < 0.001, OR = 1.93). In addition, smokers, nontea drinkers, and those with an annual household income of 10 000 yuan or less tended to have higher caries prevalence. RCI figures for the different tooth types ranged from 1% to 16%, indicating a wide variation in attack rates. In conclusion, our study suggests that root surface caries occurrence is high among the Chinese adult population, especially older adults. With an increasing number of retained teeth in both middle-aged and elderly people, root caries is a growing disease in the People's Republic of China which deserves more attention in future research.     

A comparative analysis of the efficacy of different types of filling materials in the surgical elimination of tooth perforations (experimental morphological research)

Based on the experimental morphological findings, the authors compare the efficiency of tooth perforation repair in experimental animals by surgical method using Dyract compomer, Base Line glass ionomeric cement, and Ostim-100 osteoplastic material. The data indicate a high efficiency of this method. Base Line material is preferable for filling the perforation in dental wall, as it reliably performed the isolating function under experimental conditions.     

Vibration characteristics of dental high-speed turbines and speed-increasing handpieces

Objectives

Vibrations of dental handpieces may contribute to symptoms of hand-arm vibration syndrome in dental personnel and iatrogenic enamel cracking in teeth. However, methods for measuring dental handpiece vibrations have previously been limited and information about vibration characteristics is sparse. This preliminary study aimed to use a novel approach to assess the vibrations of unloaded high-speed handpieces in vitro.

Methods

Maximum vibration displacement amplitudes of five air turbines and two speed-increasing handpieces were recorded whilst they were operated with and without a rotary cutting instrument (RCI) using a scanning laser vibrometer (SLV).

Results

RCI rotation speeds, calculated from frequency peaks, were consistent with expected values. ANOVA statistical analysis indicated significant differences in vibrations between handpiece models (p < 0.01), although post hoc tests revealed that differences between most individual models were not significant (p > 0.11). Operating handpieces with a RCI resulted in greater vibrations than with no RCI (p < 0.01). Points on the head of the handpiece showed greater vibration displacement amplitudes than points along the body (p < 0.01).

Conclusions

Although no single measurement exceeded 4 μm for the handpieces in the current test setup (implying that these vibrations may be unlikely to cause adverse effects), this study has formed the basis for future work which will include handpiece vibration measurements whilst cutting under clinically representative loads.     

广州市991名老年人根面龋RCI值调查分析

目的：调查广州市老年人根面龋的患病状况。方法：采用分层多阶段抽样方法,选取广州市城区的3个区和郊区的2个县级市作为调查点,共调查广州市65-74岁组老年人991名。以根面龋指数（Rootcariesindex,RCI）分析其患病状况。结果：上颌第一磨牙发生根面龋的RCI值最高,其次是下颌第三磨牙和上颌尖牙。上颌近中面RCI值最高（3.99%）,其次为远中面（3.67%）;下颌唇颊面最高（2.33%）;全口远中面最高（2.89%）,其次是近中面（2.87%）。舌腭面RCI值均为最低。上颌各牙面RCI值高于下颌。大部分患根面龋的老年人仅累及1个根面（84.6%）,累及2个根面的占12.0%,累及3个及以上根面的发生率很低。就患牙数目而言,根面龋牙数1颗者占24.8%,2-7颗者占24.7%,8颗及以上者仅有0.6%。结论：在根面暴露的情况下,受根面龋侵袭比例最高的是上颌第一磨牙,其次是下颌第三磨牙和上颌尖牙;易感牙面为上颌邻面和下颌唇颊面;上颌牙患龋危险性高于下颌。     

Adult root caries survey of two similar communities with contrasting natural water fluoride levels

For a comparative study of root caries, 502 adult lifelong residents of a naturally fluoridated community (1.6 ppm F) and 465 such residents of a nearby, comparable nonfluoridated community (0.2 ppm F) were examined. Substantially fewer carious lesions were found among adults in the fluoridated community relative to the nonfluoridated community. This was observed in virtually all age- and gender-specific groups. Given a cross-sectional design and considering only exposed root surfaces, root caries was related to age. In addition, the data from this study show that the number of root caries lesions is underestimated but that root caries prevalence is overestimated by the standard Root Caries Index (RCI). A less restrictive form of the RCI may lead to more valid estimation of root caries prevalence.     

Root filling materials and techniques: bioceramics a new hope?

Instrumentation creates space for canal irrigation, disinfection and root filling. All of these have an impact on the method and size of instrumentation, depending on the philosophy of the dentist and the limitations and requirements set by the equipment used in each phase, especially in root filling. Optimal root filling has many requirements which have been difficult if not impossible to fulfill. Gutta-percha has been and still is the core material of choice in root fillings, but it requires the use of a sealer in order to obtain better short term and long term seal. However, numerous studies on leakage after root filling have suggested that complete, permanent sealing of the canal against leakage from the oral cavity is usually not obtained. This review takes a critical look at presently available methods for canal instrumentation and filling, and challenges these as far less than optimal with regard to ease of operation, time and technical skills required, weakening of the root/tooth structure and quality of the seal. The authors discuss the above factors from the point of view of bioceramic materials in root filling. Is there a hope of a better future in root filling?     

Influence of the canal contents on the electrical assisted determination of the length of root canals

The purpose of this study was to compare the influence of the root canal status on the determination of the root canal length by an electronic apex locator in vital and necrotic canals and canals with root canal filling retrieval. One hundred seven teeth with a total of 171 canals with various contents (105 vital pulp, 47 necrotic pulp, and 19 retrieval of root canal filling materials) were measured for root canal length in vivo with the AFA Apex Finder. The distance between the file tip and the radiographic apex was also determined on radiographs. In 86% of the evaluated roots, the file tip position as indicated by the Apex Finder was located within 0.5 mm of a point 1.0-mm short of the radiographic apex. The Apex Finder showed higher accuracy for determining the apical constriction in vital canals (93.9%) than in necrotic canals (76.6%), and this difference was statistically significant (p < or = 0.05). The Apex Finder indicated the point -1 mm +/- 0.5 mm in canals with retrieval of root canal filling materials in 68.4% of these cases, but because of the small number of retrieval cases, this is not comparable statistically with vital and necrotic cases. The authors concluded that the AFA Apex Finder is highly accurate in vital canals.     

Epidemiologic studies. I. Secondary caries in tooth areas restored by silver-tin-amalgam, silicate cement or inlays]

On the basis of epidemiologic studies on 10 106 sugjects from the population of the town of Rostock, the authors deal with the frequency of filled tooth areas and their affection by secondary caries with special regard to filling materials (silver-tin amalgam, silicate cement, inlay). The low frequency of secondary caries in tooth areas restored by means of inlays is noteworthy. Finally, the authors give recommendations for practice.     

The late results of using evicrol and stomadent for eliminating dental tissue defects in children]

Clinical analysis of the efficacies of evikrol and stomadent used to replace dental hard tissue defects in children has shown similar results, but stomadent is preferable because the filling made of it virtually does not change its color. The authors claim that the development of such complications as caries recurrence, change of the color of the filling in sites of their union with dental tissues, abnormal edge union is related to the technique of enamel acid tanning of immature children's teeth, that should be modified.     

The dental status of dentate institutionalized older adults: consideration of retained roots

Many studies have described the general dental findings in institutionalized older patients, but few studies have used standard dental indices to describe the dental status of these populations. Eighty-five dentate nursing home residents were examined by a single dentist. Dental findings were reported by means of the DMFS, DMFT, and RCI indices along with the D/DFS ratio for coronal and root caries. The mean DMFS, DMFT, and RCI were 97.0, 22.9, and 28.7%, respectively. The percentages of untreated coronal and root caries lesions, as measured by the D/DFS ratios were 65.4% and 85.4%, respectively. Forty-eight percent of the subjects had at least one retained root, with a mean of 1.0 for all 85 subjects. None of the dental findings was statistically significant in association with age, gender, or length of stay in the institution. In the population examined, no statistical or clinical differences in relation to age, gender, or length of stay in the institution were found. The dental status of a dentate older adult population can be accurately described by means of the standardized indices of DMFS, DMFT, and RCI along with the D/DFS ratios, with the caveat that these indices must be interpreted differently than when used with pediatric populations. Retained roots present a fifth surface at risk for root caries, the occlusal surface. The role of the occlusal root surface in the dental status of a population needs to be reported and analyzed.     

Retrograde filling material in periapical surgery: a systematic review

Background Periapical surgery focuses on the treatment of teeth with persistent periapical lesions when orthograde root canal treatment fails. Although MTA® is the gold standard material for retrograde filling, Biodentine® - a tricalcium silicate-based cement - has been proposed in order to resolve several of its limitations. A systematic review has been carried out to compare the physicochemical properties of Biodentine® versus MTA® as root-end filling material in periapical surgery. Material and Methods An electronic search was conducted by two independent examiners during March 2020 in the Cochrane, PubMed-MEDLINE and Scopus databases. In addition, a manual search was made in specialized journals. Comparative human or in vitro studies that evaluated bond strength, the presence of marginal gap and sealing ability were included. No restriction on publication date was applied. Animal studies, clinical cases, cases series and expert opinions were excluded. Results After analyzing 147 initially selected studies, 13 publications were included. Regarding bond strength, the studies seemed to evidence better performance of Biodentine® in both acidic and blood contaminated environments. In relation to the presence of marginal gap and sealing ability, the studies yielded contradictory results. According to some authors, the sealing ability of Biodentine® is greater than that of MTA® during the first 24 hours, though both materials prove equal after one week. Other authors recorded no significant differences. Conclusions Considering the limitations and heterogeneity of the studies included, there is not sufficient evidence to confirm the clinical superiority of Biodentine® as a root-end filling material in periapical surgery. Key words:Biodentine, MTA, retrograde filling, periapical surgery.     

数字化曲面体层标记位点放大率的实验研究

目的:探讨数字化曲面体层(PTG)的标记位点放大率。方法:以曲面体层机颏托上的U型标记杆及以干燥下颌骨的正常摆放位置为参照,将种植用钢珠按牙弓形态进行唇舌向网点式排布,进行位点设置,按1-8区牙位排列放置钢珠,类似同心圆状辐射排列,位点间距10mm,逐点拍摄,进行投照后在PACS上高清晰显示屏进行测量所得图像的水平向及垂直向数值,对图像进行分析,得出放大率,再进行部位分析,构建体层域。结果:水平向放大率较垂直向为显著,U型标记杆覆盖范围为前牙及双尖牙区,其唇侧水平向放大率均小于1,舌侧水平向放大率均大于1,后磨牙区图像垂直向与水平向均为放大。结论:不同位置的钢珠图像放大率不同,坐标相交点即为同等放大率位置,即位于体层域中心,体层域为显示图像较为真实的扫描区域,体层域唇侧图像水平向缩窄舌侧图像水平向放大,而垂直向均显示放大,变化倍率以水平向为显著(P<0.01),以此来指导临床上对曲面体层片的判读。     

Clinical study on the effect of amine fluoride/stannous fluoride on exposed root surfaces.

The aim of this study was to assess the remineralizing effect of an amine fluoride (AmF)- and stannous fluoride (SnF2)-containing toothpaste and mouthrinse on exposed root surfaces. A total of 44 adults participated in the 20-week, double-blind study and were grouped as follows: (1) 20 participants (mean age 45.7 years) used an AmF/SnF2 experimental toothpaste plus AmF/SnF2 (Meridol) mouthwash, and (2) 24 participants (mean age 48.8 years) used an NaF-containing toothpaste and mouthrinse. Root caries index (RCI) and root surface scores were determined by a modified method of Katz (J Dent Res, 1984). RCI mean values showed decreases of approximately 47% in the AmF/SnF2 group, and 10% in the NaF group. With respect to root caries scores, the number of persons with decreased softened (non-carious) surfaces between the baseline and control examinations was statistically significant (p less than 0.05) in the AmF/SnF2 group but not significant in the NaF group. A statistically significant difference (p less than 0.05) in the results of the groups favored the AmF/SnF2 subgroup. Thus, the data point to a possible remineralizing effect of topically applied AmF/SnF2 on softened root caries surfaces.     

Critical evaluation of the results of systematic pedodontic care]

The authors present and comment upon the clinical and radiological findings obtained from 1200 children in the framework of a caries-statistical cross-sectional study. The statistical data are subdivided into: state of oral rehabilitation, extent of oral rehabilitation, frequency of the different kinds of filling and endodontic treatment measures.