Comparison of clinical practice education in dental hygiene schools in eight countries

Objectives: The profession of dental hygienist is one of the few in which the primary function of the practitioner is to prevent oral disease and to promote the well‐being of patients. The aim of this study was to investigate clinical training conditions in schools of dental hygiene in eight countries (the USA, Canada, the UK, Sweden, Denmark, Thailand, South Korea and Japan). Methods: In 2006, we sent out a questionnaire in which we asked dental hygiene schools about how they educate dental hygiene students. Results: The techniques taught to students in schools in Western industrialised nations, such as the USA, Canada, Denmark, the UK and Sweden, were mainly related to dental preventive measures and dental health guidance. By contrast, training schools in South Korea and Japan placed less emphasis on dental preventive measures and dental health guidance. Dental hygienists in Thailand are trained to perform local anaesthesia and to fill and extract deciduous teeth although the country does not have a specific qualification system. Conclusions: The contents of clinical training and education in schools of dental hygiene differ greatly among countries.     

Sero-epidemiological study on hepatitis A and B virus infection among dentists in the Philippines

Dentists in the Philippines were surveyed for evidence of past hepatitis A and B virus infections. Of the 234 dentists examined, 201 (85.9 per cent) were found to have been infected by HA virus and 137 (58.5 per cent) had been infected by HB virus. The proportion with evidence of past HB virus infection increased as the years in dental practice increased. This increment with age was not found in the general population of the Philippines. It is considered that the incremental pattern could be attributed to the summation of risk during many years of providing dental treatment. Comparing the proportion of dentists with HBV antibodies (anti-HBs/c) in the Philippines, Japan, USA and Denmark, the Philippine dentists were found to be more frequently infected than dentists in the other countries. However, the increment in the proportion positive for HBV as the years in practice advanced was consistent with that found in Japan. The prevalence of post HA virus infection in Philippine dentists was higher than the proportion for dentists in Japan but in both countries it is probable that dentists are infected at the same rate as the general population.     

Panoramic and restrictive intraoral radiography in comprehensive oral radiographic diagnosis

It has been suggested that information from the panoramic radiograph makes it possible to appropriately select supplementary intraoral radiographs to achieve a comprehensive examination of teeth and surrounding bone with less patient dose but no significant information loss. Number of intraoral radiographs selected, information loss and monetary costs with such a procedure was evaluated in 40 patients. Results show that, on average, 5.1 intraoral radiographs were selected to supplement the panoramic radiograph. Of these, 3.1 contained information different from that in the panoramic radiograph but 2.0 did not. An additional 3.4 ought to have been taken to reach the result of the 'gold standard' achieved from a simultaneous evaluation by two expert observers of panoramic radiographs and full mouth surveys with intraoral radiographs. Sensitivity for the combined use of panoramic and supplementary intraoral radiographs was high (80–96%, depending on type of teeth) as regards periapical lesions and marginal bone loss but low for caries (42–96%). Specificity was high for periapical lesions and caries (95–97%) but low for marginal bone loss (50–92%). In Sweden, patient costs become almost the same for a combination of panoramic radiography and 8.5'intraoral radiographs as for a full mouth survey comprising 20 intraoral radiographs. The radiation dose reduction is 40–50% considering that the dose from a panoramic radiograph approximately corresponds to 2–4 intraoral radiographs. We conclude that using panoramic radiography in combination with selected intraoral radiographs is possible if the radiographic examination is preceded by a thorough clinical examination and the following parameters are correctly evaluated before the examination: patient category, radiation dose, information loss, patient discomfort, time consumption and monetary costs.     

Linear or curved display of digital radiographs: Results of a “beauty contest”

CCD detectors used in direct digital intraoral radiography have a linear dose response. When images are displayed on computer monitors a linear display function is also most often employed. Dentists using digital radiography have pointed out that the visual characteristics of such images are different from those of film based images. The aim of the present work was to study the effects of curving the display function. For this purpose 30 digital radiographs were selected, and a computer program was constructed by which the gray level display could be manipulated. Dentists at Osaka University, Osaka, Japan, and Karolinska Institutet, Stockholm, Sweden, were asked to manipulate the display of each individual radiograph so that it exhibited what subjectively appeared to be the best possible characteristics for diagnostic work. The viewers were in agreement in their preference for a curved display function for digital intraoral radiographs. Effects of the curved display are analyzed and discussed. It is concluded that from a purely subjective point of view the dose response function of digital intraoral radiographs should be curved in such a way that contrast is increased in areas with low exposure and decreased in areas with high exposure. Whether or not this has an effect on the diagnostic performance may be studied employing, for example, example, ROC techniques.     

World dental research production: an ISI database approach (1999-2003)

The objective of this study was to obtain a geographic world map of scientific production in dentistry by analysing published papers. Articles and reviews in the Dentistry, Oral Surgery & Medicine category published from 1999 to 2003 were accessed through the ISI database. The data were analyzed quantitatively (number of documents, number of researchers, productivity, interannual variation rate and relative specialization index), qualitatively (weighted impact factor, relative impact factor, citation rate per document and top 5 publications) and socioeconomically (number of documents per inhabitant and per dentist and in relation to the country's GDP). The USA, UK, Japan and Scandinavian countries were found to be the most productive countries (number of publications). Publications from Scandinavian countries were also of high quality as measured by Impact Factor and Citation Rate, while the UK had one of the highest productivity rates (number of documents per researcher).     

A Cost Analysis Comparing Xeroradiography to Film Technics for Intraoral Radiography

In the United States during 1978 $730 million was spent on dental radiographic services. Currently there are three alternatives for the processing of intraoral radiographs: manual wet-tanks, automatic film units, or xeroradiography. It was the intent of this study to determine which processing system is the most economical. Cost estimates were based on a usage rate of 750 patient images per month and included a calculation of the average cost per radiograph over a five-year period. Capital costs included initial processing equipment and site preparation. Operational costs included labor, supplies, utilities, darkroom rental, and breakdown costs. Clinical time trials were employed to measure examination times. Maintenance logs were employed to assess labor costs. Indirect costs of training were estimated. Results indicated that xeroradiography was the most cost effective ($0.81 per image) compared to either automatic film processing ($1.14 per image) or manual processing ($1.35 per image). Variations in projected costs indicated that if a dental practice performs primarily complete-mouth surveys, exposes less than 120 radiographs per month, and pays less than +6.50 per hour in wages, then manual (wet-tank) processing is the most economical method for producing intraoral radiographs.     

Dental conditions in middle-aged and older people in Denmark and Sweden: a comparative study of the influence of socioeconomic and attitudinal factors

In 1998-99 two parallel questionnaire studies were performed in Denmark and Sweden. In Denmark the age group was 45-69 years and in Sweden 55-79 years. One aim was to study the influence of socioeconomic and attitudinal factors on dental status in the two countries. For the comparable age groups 55-69 years there was a striking difference in dental conditions between the countries. In Sweden, 72% had either all teeth remaining, missing teeth replaced by fixed prosthodontics, or only one or two single missing teeth not replaced. The corresponding figure for Denmark was 44%. Among Danes, 34% were wearing removable denture(s) or were edentulous in one jaw or both jaws, compared with 15%, among Swedes. In logistic regression models, higher income and longer education were significantly associated with the best dental status categories in Denmark but not in Sweden. In the model with wearing removable denture(s) as the dependent variable, lower income and lower education level showed a significant influence for the Danes. In Sweden, lower income showed a significant influence but education level was insignificant. In both Denmark and Sweden, a positive attitude toward the importance of dental appearance was associated with an increased risk of wearing removable denture(s).     

Dental conditions in middle-aged and older people in Denmark and Sweden: a comparative study of the influence of socioeconomic and attitudinal factors

In 1998-99 two parallel questionnaire studies were performed in Denmark and Sweden. In Denmark the age group was 45-69 years and in Sweden 55-79 years. One aim was to study the influence of socioeconomic and attitudinal factors on dental status in the two countries. For the comparable age groups 55-69 years there was a striking difference in dental conditions between the countries. In Sweden, 72% had either all teeth remaining, missing teeth replaced by fixed prosthodontics, or only one or two single missing teeth not replaced. The corresponding figure for Denmark was 44%. Among Danes, 34% were wearing removable denture(s) or were edentulous in one jaw or both jaws, compared with 15% among Swedes. In logistic regression models, higher income and longer education were significantly associated with the best dental status categories in Denmark but not in Sweden. In the model with wearing removable denture(s) as the dependent variable, lower income and lower education level showed a significant influence for the Danes. In Sweden, lower income showed a significant influence but education level was insignificant. In both Denmark and Sweden, a positive attitude toward the importance of dental appearance was associated with an increased risk of wearing removable denture(s).     

Image quality of digital and film radiographs in applications sent to the Dental Insurance Office in Sweden for treatment approval

In July 2002, a new dental insurance program was introduced in Sweden. For all patients over 65 years, prior approval for all prosthetic work would need to be obtained from the Dental Insurance Office. From October to December 2002, 540 cases were randomly selected for evaluation from the 14,624 applications that had been sent from throughout Sweden to the Dental Insurance Office in Lund. Our aims were to appraise the quality of the radiographic examinations and to compare the quality of the digital with the film (X-ray film) radiographs. The radiographic examinations were evaluated as a whole in relation to the proposed treatment and in detail using specific criteria such as density, contrast, unsharpness, angulation, and receptor position error. The quality variables were evaluated as acceptable or unacceptable. A total of 4,687 intra-oral and 206 panoramic radiographs were evaluated. Thirteen per cent of the intra-oral radiographs and 9% of the panoramic radiographs were taken with a digital technique. Most of the digital radiographs--7o% of the intra-oral and 61% of the panoramic radiographs--were submitted on microdisk. Twenty-eight per cent of the intra-oral digital radiographs, however, were submitted on paper. The radiographic quality in 15o cases (28%) were found to be unacceptable for assessment of the proposed treatment. The most common error--both in digital and X-ray film radiographs--was in receptor position. Significantly more errors were found in the intraoral digital radiographs compared to the radiographs taken with X-ray film. Most of the errors in the digital radiographs were detected in the paper copies. In conclusion, it is possible to improve the radiographic quality in applications for treatment approval, and the dentists had more difficulties with the digital technique than with X-ray film.     

Comparison of trends in the prevalence of caries and restorations in young adult populations of several countries

We compared DMFT (decayed, missing and filled teeth) values of young adult populations (about 18- to 21 yr old) obtained over two decades in five industrialized countries (Denmark, Finland, Israel, Japan, U.S.A.). Trends of the active disease factor (D) and treatment factor (F) within and between these countries during two decades were also compared. No uniform trend in caries prevalence data, based on total DMFT scores, was found. In some countries DMFT scores declined (Denmark, U.S.A.), in some they remained relatively static (Finland), and in some they increased during the last 20 yr (Israel, Japan). However, DMFT scores did not always correlate with untreated lesions, D, which decreased remarkably in Denmark and Finland and moderately in the U.S.A., remained stable in Japan, but increased in Israel. Similarly, treatment of caries, F, varied in different countries, increasing dramatically in Finland and Japan and moderately in Israel, remaining static in Denmark, and decreasing in the U.S.A. These trends appear to be influenced largely by the extent of caries-preventive measures (particularly fluorides) in the respective countries, and to a lesser degree by sugar utilization and the availability of dental personnel. This age population has not been studied in a comparative fashion previously. This study also emphasizes the importance of looking not only at DMFT scores but at the trends in meeting treatment needs, D vs F scores.     

Quality of intraoral radiographs sent by private dental practitioners for therapy evaluation by the Social Insurance Office

Nearly all Swedish private dentists are affiliated with the Dental Care Insurance. Proposed treatment plans, including radiographs, are submitted to the Social Insurance Office for prior approval. In this study the quality of a sample of intraoral radiographs submitted by 404 private dental practitioners was analysed. Forty-four per cent of 3,708 periapical radiographs, simultaneously evaluated by two examiners, were satisfactory. The most frequent errors were excessive vertical angulation (18 per cent), missing apex (12 per cent), film positioning error (11 per cent) and underexposure (10 per cent). Fifty-five per cent of 294 bitewing radiographs were satisfactory; the major error was missing bone margin (33 per cent). The radiographs of 15 per cent of the 2,844 teeth proposed for therapy had insufficient radiographic documentation, six per cent because of missing radiograph and nine per cent because of missing apex on the radiograph. These errors applied to every second dentist. Compared to a similar study ten years ago, the present results do not indicate that the quality of intraoral radiographs has improved.     

Intraoral radiographic errors.

The purpose of this investigation was to investigate intraoral radiography in regards to the frequency of errors, the types of error necessitating retakes, and the relationship of error frequency to the teeth area examined and type x-ray cone used. The present study used 283 complete mouth radiographic surveys made, and 890 radiographs were found to be clinically unacceptable for one or more errors in technique. Thirteen and one-tenth errors per one hundred radiographs were found in this study. The three major radiographic errors occurring in this study were incorrect film placement (49.9 percent), cone-cutting (20.8 percent), and incorrect vertical angulation (12.5 percent).     

CBCT在慢性牙周炎诊断中的应用

目的研究锥形束CT在慢性牙周炎诊断中的应用。方法拍摄30例慢性牙周炎患者锥形束CT片和曲面断层片,观察796颗牙近远中、及颊(唇)、舌侧牙槽骨吸收情况。并通过锥形束CT对其中60颗单根牙近、远中和颊(唇)、舌侧8个位点的牙槽骨吸收情况进行测量取均值,与曲面断层片测量得的近、远中牙槽骨吸收均值进行比较。结果锥形束CT片和曲面断层片均可明确显示近、远中牙槽骨吸收情况,两者之间比较差异无统计学意义(P>0.05)。锥形束CT测得牙齿近、远中牙槽骨吸收的均值与曲面断层片测得的均值比较,差异有统计学意义(P<0.05)。锥形束CT在判断颊(唇)、舌侧骨吸收及根分叉病变方面,明显优于曲面断层片。结论锥形束CT比曲面断层片对慢性牙周炎牙槽骨吸收的诊断更加准确。     

Origins and benefits of dental hygiene practice in Europe

Origins and benefits of the practice of dental hygiene were investigated in order to provide guidelines to countries where initiatives are being taken to introduce the profession. In Europe, so far the profession has been introduced in the Czech Republic, Denmark, Great Britain, Finland, Italy, Latvia, Lithuania, the Netherlands, Norway, Portugal, Sweden, Switzerland and Spain. Programmes in Ireland, Poland, and Romania are not presented in this article. Information for this study was obtained using questionnaires and followed up by e-mail correspondence with additional experts, supporting studies and reference literature. All experts consulted are involved in the professional and educational organisation of dental hygiene in their countries. Results show that dentists and dental hygienists who had been inspired by the delivery of preventive care in the US, initiated the European dental hygiene movement. In some countries, opposition of organised dentistry had to be overcome. In countries where the population has limited access to qualified dental hygiene care, such as in Austria, Belgium, Germany and France, a high prevalence of untreated periodontal disease has been reported. There, the lucrative practice of delegating dental hygiene tasks to dental assistants without qualifying education has slowed efforts to implement the profession and resulted in negative health and vocational outcomes. This leads to the conclusion that an implementation of legislation governing the practice and the educational process of dental hygiene in the EU and beyond would contribute to an equitable standard of health care as well as to equal opportunities in education and employment.     

Rotational panoramic radiography in epidemiological studies of dental health. Comparison between panoramic radiographs and intraoral full mouth surveys

In conjunction with an epidemiological study of oral health in women the capacity of the panoramic radiograph to yield information on oral conditions was compared to that of the intraoral full mouth survey including posterior bitewing radiographs. Full mouth surveys and panoramic radiographs of 75 women were compared for gross characteristics such as distribution of teeth, missing teeth, restorations, and endodontic treatment as well as for osteolytic lesions at the root, marginal bone loss and carious lesions. A nearly 100% agreement was found for gross characteristics but also for osteolytic lesions associated with teeth and for marginal bone loss the agreement was good; osteolytic lesions at single rooted teeth 76%, multirooted teeth 90% and a coefficient of correlation of .96 for individual mean marginal bone scores. Poor agreement was found for carious lesions as only 36% of those extending well into the dentine were found both in the intraoral radiographs and in the panoramic radiographs. It may be included that, except for carious lesions, the panoramic radiographs can be considered a useful tool in epidemiological studies of oral health.     

Utilization of dental health services among middle-aged people in Sweden and Denmark

In 1999, questionnaires were sent to random samples of 1001 Swedish citizens aged 55-79 years and 1175 Danish citizens aged 45-69 years. Various questions were asked concerning dental conditions, dental visit frequency per year, and money spent annually on dental care, etc. The objectives were to assess differences in the utilization of dental services and to compare out-of-pocket costs for dental care in Sweden and Denmark with control for age, gender, dental conditions and income. More than 80% of the subjects reported that a dentist had examined them less than 1 year previously. However, 77% of the Danes reported dental visits twice a year or more compared to 28% of the Swedes. Although the Danes reported a more frequent use of dental services, they had poorer dental conditions compared to the Swedes. Even though the Swedes used dental services less often than the Danes did, more subjects reported high 12-month out-of-pocket costs. In the present study, separate models were constructed for the two countries because there could be different mechanisms at play, as indicated by the results. The different insurance systems along with different degrees of commercialization in the two countries might be the most decisive factors in this context.     

Utilization of dental health services among middle-aged people in Sweden and Denmark

In 1999, questionnaires were sent to random samples of 1001 Swedish citizens aged 55-79 years and 1175 Danish citizens aged 45-69 years. Various questions were asked concerning dental conditions, dental visit frequency per year, and money spent annually on dental care, etc. The objectives were to assess differences in the utilization of dental services and to compare out-of-pocket costs for dental care in Sweden and Denmark with control for age, gender, dental conditions and income. More than 80% of the subjects reported that a dentist had examined them less than 1 year previously. However, 77% of the Danes reported dental visits twice a year or more compared to 28% of the Swedes. Although the Danes reported a more frequent use of dental services, they had poorer dental conditions compared to the Swedes. Even though the Swedes used dental services less often than the Danes did, more subjects reported high 12-month out-of-pocket costs. In the present study, separate models were constructed for the two countries because there could be different mechanisms at play, as indicated by the results. The different insurance systems along with different degrees of commercialization in the two countries might be the most decisive factors in this context.     

Fear of amalgam: dentists' experiences in the Nordic countries.

The purpose of the present investigation was to study Nordic dentists' experiences with patients concerned about the possible adverse effects of dental restorations, their perceived ability to deal with this problem and their views as to the suitability of amalgam as a filling material. A random sample of practising dentists in Denmark, Finland, Norway and Sweden were sent a questionnaire in spring 1990. Responses were received from 1732 dentists (65 per cent). In 1989, virtually every dentist had seen patients concerned about possible adverse effects of their dental restorations. The reported mean number of such patients per dentist per year was 80.5 (SD = 128.1) in Denmark, 39.3 (SD = 68.4) in Finland, 83.3 (SD = 194.1) in Norway, and 124.4 (SD = 210.3) in Sweden. Ninety-two per cent of the patients' questions concerned amalgam fillings. About 70 per cent of the dentists believed that inexplicable symptoms associated with amalgam fillings had a psychosomatic background. Only about a fifth of the respondents felt able to examine such patients without seeking medical expertise. In the absence of oral or medical indications, 65 per cent of the respondents in Sweden and 77 per cent in the other countries considered that dentists should advise patients against having their amalgam fillings replaced. About 5 per cent of the respondents were ready to stop using amalgam in the near future.     

Comparative study of cone beam computed tomography and intraoral periapical radiographs in diagnosis of lingual-simulated external root resorptions

Abstract – Background: Owing to a lack of symptoms and difficult visualization in routine intraoral radiographs, diagnosis of external root resorptions can be challenging. Aim: The goal of this study was to compare two image acquisition methods, intraoral radiographs and cone beam computed tomography (CBCT), in the diagnosis of external resorption. Material and Methods: Thirty‐four maxillary and mandibular bicuspids were divided into three groups. Perforations measuring 0.3 and 0.6 mm in diameter and 0.15 and 0.3 mm in depth, respectively, were made on the lingual root surfaces in thirty teeth, and four were used as controls. Next, teeth were mounted on an apparatus and radiographed at mesial, distal, and orthoradial angulations. CBCT images were also taken. The analysis of the intraoral radiographic and tomographic images was carried out by two experts using standardized scores. Data were then compared statistically. Results: A strong agreement between the examiners was observed in both diagnosis methods, the intraoral radiographic (r = 0.93) and the tomographic analysis (r = 1.0). Tomography had higher statistically significant detection values than intraoral radiography (P < 0.05). In intraoral radiographs, the detection was significantly greater (P < 0.05) in the mandibular bicuspids, compared with their maxillary counterparts. The ability to detect 0.6‐mm perforations by intraoral radiography was significantly higher than that of 0.3‐mm perforations (P < 0.05). Conclusion: Cone beam computed tomography showed better diagnostic ability compared with intraoral radiography, regardless of the tooth or the dimensions of the resorption evaluated.