Assessing current clinical eruption stage of mandibular third molars by dental panoramic radiography.

OBJECTIVE: We examined whether dental panoramic radiography (PAN) can be used to identify the clinical stage of eruption of mandibular third molars at the time of radiological examination. MATERIALS AND METHODS: Cross-sectional data included records from clinical oral examination and PANs of university students. In the retrospective analysis of 345 mandibular third molars in 189 participants (20% men, 80% women; mean age 20.7 years; standard deviation [SD] ± 0.6), clinical stages of eruption were compared with their radiographic depth in bone, inclination, and root development. Statistics included χ2, Mann-Whitney U tests, and logistic regression. RESULTS: Significant (p < 0.001) predictor variables for assessing the clinical stage of eruption were radiographic depth in bone and inclination. All teeth radiologically at a depth of the cementoenamel (CE) junction of the neighbouring second molar or deeper were clinically unerupted. Above the CE junction, 80% of vertical and 97% of distoangular teeth were connected to the oral cavity, and 82% of mesioangular and 69% of horizontal teeth were clinically unerupted. CONCLUSION: All teeth below or at the CE junction are clinically unerupted. Above the CE junction, stage of eruption should be assessed together with the inclination, but horizontally inclined teeth are recommended to be verified clinically.

Factors affecting number of third molars extracted in a single visit.

OBJECTIVE: This cross-sectional study evaluated the number and characteristics of third molars extracted in a single visit in primary care and their associations with patient's age and sex and operator's experience. MATERIALS AND METHODS: The data included all appointments where routine and surgical extractions of third molars were performed in 2016 in primary care of the City of Helsinki. Statistics included χ2 and Mann-Whitney U tests, and binomial logistic regression. RESULTS: In total of 10,894 appointments, the number of extracted third molars was 12,728, yielding an average of 1.2 third molars per visit. Mean age of patients (55% women, 45% men) at extraction was 32.2 years (range 12 - 97 years). Most appointments (83.7%, n = 9,118) comprised extraction of one, 15.8% two, 0.4% three, and 0.1% four third molars. Number of teeth extracted at a time did not differ by sex. Increasing age was associated with a reduction in the likelihood of several third molar extractions in a visit (OR 0.96; 95% confidence interval (CI) 0.96-0.97). Multiple third molars were extracted significantly more likely if the operator was experienced (OR 2.32; 95%CI 1.90-2.84). Multiple extractions were also associated with the mandible, operative extractions, unerupted teeth and caries. CONCLUSIONS: Third molars were typically extracted one at a time. In health care units, it is appropriate to consider extraction of several third molars in a single visit, if need for extraction of other third molars exist. Concentrating the extractions of younger patients on experienced operators would reduce the number of patients' visits.

Level of difficulty of tooth extractions among roughly 100,000 procedures in primary care.

OBJECTIVES: The study examined treatment codes of extracted teeth and aimed to assess degree of difficulty concerning all tooth extractions. MATERIALS AND METHODS: Retrospective data on treatment codes of all tooth extractions during a two-year period were obtained from the patient register in primary oral healthcare of the City of Helsinki, Finland. Prevalence, indication, and method of extraction appeared in the treatment codes (EBA-codes). Degree of difficulty was determined from the method and classified as non-operative or operative and as routine or demanding. Statistics included frequencies, percentages, and χ2 test. RESULTS: Total number of extraction procedures was 97,276, including 121,342 extracted teeth. The most frequent procedure was a routine extraction of a tooth with forceps (55%, n = 53,642). The main reason for extraction was caries (27%, n = 20,889). Of the extractions, 79% (n = 76,435) were non-operative, 13% (n = 12,819) operative, and 8% (n = 8,022) multiple extractions in one visit. Level of difficulty was distributed as routine non-operative (63%), demanding non-operative (15%), routine operative (12%), demanding operative (2%), and multiple extractions (8%). CONCLUSIONS: Two-thirds of all tooth extractions in primary care were relatively simple. However, 29% of procedures were classified as demanding. CLINICAL RELEVANCE: As earlier methods for assessing level of difficulty were aimed at third molars alone, an analysis was presented for all tooth extractions. This approach may be useful for research purposes, and the profile of tooth extractions and their difficulty level may be practical also for decision-makers in primary care.

Frequency and type of tooth extractions in adults vary by age: register-based nationwide observations in 2012-2017.

OBJECTIVE: This register-based study assessed the frequency of and age-specified variation in tooth extractions in adults visiting private dentists in Finland in 2012-2017. MATERIAL AND METHODS: Retrospective study design was used on the register-based data of private sector services. Data of the entire 6 years, 2012-2017, included records of a total of 6,252,039 patients. From among these, further detailed information was gathered in 2012 for 1,058,305 patients, and in 2017, for 985,043 patients. For each 6 years, the data were aggregated into patients' 5-year age groups that were observation elements. Proportions of patients undergoing oral surgical treatments were compared during the 6 years 2012-2017, and details of tooth extractions in 2012 and 2017. Linear regression modelling was used to analyse thinkable age- and year-related inclinations in oral surgical treatments. RESULTS: Across the 6 years, a total of 848,362 patients (13.6%) underwent oral surgical treatments, and the rates varied by year 13.3-13.8%. By age group, the smallest rates (9-10%) were for 35-49-year-olds and greatest (20-22%) for those aged below 25 or over 84. The rates in same-age groups were stable. In 2012 and 2017, mean numbers of tooth extractions per patient by year were 0.17 and 0.18, and per patients undergoing oral surgical treatments, 1.29 and 1.27, respectively. Proportion of patients undergoing oral surgical treatments and mean number of tooth extractions per patient was greater in younger and older age groups. CONCLUSIONS: Tooth extractions in adults are age-dependent and age-specified differences remain stable across the years.

Retained dental roots of adults: A nationwide population study with panoramic radiographs.

The aim of this study was to assess the occurrence and nature of retained dental roots and their associations with demographics in the Finnish adult population. From the cross-sectional nationwide Health 2000 Survey of the Finnish population aged 30 years and older, 6005 participants with clinical oral examination and panoramic radiographs were included. Occurrence and characteristics of all retained dental roots were examined. Statistical analyses included χ2 , Kruskal-Wallis and Mann-Whitney U tests, and SAS-SUDAAN calculations. The mean age of the 6005 participants (46% men and 54% women) was 53 (SD 14.6) years. At least one retained dental root was observed in 13% (n = 754) of the participants. The 1350 retained roots included 461 (34%) roots retained entirely in bone and 889 (66%) partly in bone. The most common location of a retained dental root was the third molar region. Occurrence of retained roots partly in bone was associated with male sex and lower education. Occurrence of retained third molar roots entirely in bone was associated with female sex, younger age, higher education, and living in a city. Among all retained dental roots, the preponderance of third molars emphasized the demanding nature of extracting the third molar in women.

Is the third molar erupting at a younger age than before?

OBJECTIVES: The aim of this study was to update the much-cited knowledge, published over half a century ago, of the age of eruption of the third molar in the Finnish population. METHODS: The study followed a retrospective and cross-sectional protocol and included 710 digital panoramic radiographs of patients (49.3% men, 50.7% women) aged 15-23 years visiting the public oral health care services of the City of Helsinki in 2015. Age and sex of the subjects were recorded. The radiographs were examined for inclination of the third molars in both jaws and vertically located teeth were further classified into four stages of eruption: (A) in bone, (B) alveolar emergence, (C) gingival emergence, and (D) complete emergence. Statistics included chi-squared, Mann-Whitney U, and median tests. RESULTS: Of altogether 2502 third molars, 53.0% (n = 1325) were in vertical position. The median age of gingival emergence (stage C) of the third molar varied between 19.8 and 20.8 years, and the median age of reaching the occlusal level (stage D) between 20.8 and 21.8 years depending on sex and the jaw. CONCLUSION: The median ages for the third molar to pierce the gum were lower than reported over half a century ago.

Is dental panoramic tomography appropriate for all young adults because of third molars?

OBJECTIVE: The purpose of this study was to determine, if a dental panoramic tomograph (DPT) is appropriate for every young adult due to third molars. MATERIALS AND METHODS: The study sample consisted of 217 university students (20% men and 80% women; mean age 20.7 years; SD ± 0.6 years) and included a questionnaire about symptoms caused by third molars, clinical oral examination of third molars, and a DPT. Subjects were divided into the following groups: subjects with a clinical indication for a DPT and subjects without such indication. The DPTs were then examined for findings regarding third molars. RESULTS: Clinical indication for a DPT was observed in 64% of the subjects. Radiography revealed an additional 1.4% of the subjects with ≥1 radiographic signs of disease in relation to their third molars. Also, an additional 27% of the subjects had ≥1 other radiographic findings in relation to third molars that may have affected the clinical decision making. CONCLUSIONS: In our study population, clinically undetectable pathology cannot be considered as an indication for a DPT. However, if prevailing clinical practice supports preventive removals and detecting or monitoring of unerupted third molars, a referral to DPT can be considered as good clinical practice.

Prevalence of third molars determined by panoramic radiographs in a population-based survey of adult Finns.

OBJECTIVES: The aim of the study was to examine the prevalence of third molars in panoramic radiographs in a population-based study of adults aged ≥30 years. METHODS: Out of a sample of 8028 inhabitants of Finland, selected with two-staged stratified cluster-sampling method for the Health 2000 Survey, 5989 participated in clinical oral examination and panoramic radiography. Mean age was 52.5 years (SD 14.6; range 30-97 years). The following variables were included in the analysis: participant characteristics, clinical number of all teeth, and radiographic prevalence and characteristics of third molars. Statistics included chi-squared, Fisher's exact, and Kruskal-Wallis tests and SAS-SUDAAN calculations. RESULTS: A total of 5912 third molars in 47.8% of the study population were recorded from panoramic radiographs. At least one impacted third molar was found in 21.9% of the study population. More than half (57.3%) of the remaining third molars were located in the mandible. A preponderance of participants with all third molars missing were observed in the oldest age group, women, those with lower education and those living in the countryside. Third molars or remnants thereof were observed radiographically in 3.9% of clinically edentulous study population. CONCLUSIONS: The panoramic radiographs disclosed many remaining third molars in adult Finns aged ≥30 years. One-third of the third molars located impacted which may cause unexpected need for care.

How many third molars remain unnoticed in a population survey without panoramic radiographs?

OBJECTIVE: The aim of the study was to compare the findings of clinical examination and panoramic radiograph regarding the occurrence of third molars in a population survey to find out how many third molars remain clinically unnoticed. MATERIALS AND METHODS: A two-staged stratified cluster-sampling method was used to select 8028 participants representing the adult population aged 30 years and older. Clinical oral examinations and panoramic radiographs were carried out for 5989 subjects (46% men, 54% women; mean age 52.5, SD 14.6; range 30-97 years). Clinical recordings of the presence of third molars were compared with the radiographs. Statistics included chi-squared, Fisher's, Wilcoxon's, and Kruskal-Wallis tests. RESULTS: In the 5989 subjects, 3742 third molars were recorded in the clinical examination, and 5912 were observed in the panoramic images, a difference of 2170 teeth. Furthermore, related to 3668 (61%) of the third molars, both clinical and radiographic recordings were attributed to the same third molar, while 2244 third molars were observed only in the panoramic image, and 74 only in the clinical examination. In every age group, the mean number of third molars per subject was larger radiographically compared with the clinical recordings (means for all 0.99 vs. 0.62; P < 0.001). CONCLUSION: Numbers of third molars, recorded in clinical examination alone, are underreported by approximately one-third compared with radiographic findings. CLINICAL RELEVANCE: The numbers of third molars in a population survey without a panoramic radiograph do not reflect the total number of third molars in a population.

Did malpractice claims for failed dental implants decrease after introduction of CBCT in Finland?

OBJECTIVES: To examine the role of cone beam computed tomography (CBCT) in preventing failures in implant treatment. We hypothesize that the number of malpractice claims related to dental implant treatment would decrease after the first CBCT device came available in 2002 in Finland. MATERIAL AND METHODS: Data concerning malpractice claims related to dental implant treatment during the years 1997-2011 were collected from the Finnish Patient Insurance Centre (N = 330 subjects). We selected the cases that might have benefitted from the use of CBCT examination. These cases (n = 131) led to financial compensation due to permanent inferior alveolar nerve injury, improper implant position, or insufficient amount of bone for the implant. The annual total number of inserted dental implants, CBCT devices, and CBCT examinations in Finland were drawn from the national registers and used to estimate the impact of CBCT in preventing treatment failures. RESULTS: The most common reason for all failures (n = 268 implants) was an improper implant position (46.3%). The most common area of malpractices was upper front teeth (34%). We have noticed a fall in the rate of compensable malpractice cases concerning implant failure, simultaneously with CBCT technology emerging on the market. CONCLUSIONS: There may be an association between the increasing availability of CBCT equipment and the reducing frequency of compensable malpractice claims. CLINICAL RELEVANCE: It is possible that the use of CBCT may result in fewer compensable malpractice claims.

What kind of third molars are disease-free in a population aged 30 to 93 years?

OBJECTIVES: The aim of the study was to characterize third molars that have remained disease-free in a representative sample of the Finnish population aged 30 years and older. MATERIALS AND METHODS: Two-staged stratified cluster sampling (N = 8028) was used, and 6005 subjects participated in a clinical oral examination and panoramic radiography. Disease-free third molars were characterized as follows: no dentinal caries, no filling, periodontal pocket depths of neighboring second molars less than 4 mm, and no radiographic pathological findings. Logistic regression analyses served for assessment of the strength of characteristics of third molars for disease-free status. RESULTS: Of the subjects, 2653 (44%) had at least one third molar. Of them, the majority (62%) had only diseased third molars, 16% had only disease-free ones, and 22% had both. Participants had in total 5665 third molars; 29% of them were disease-free. Female gender, higher level of education, and younger age were related to disease-free status (P < 0.001). Disease-free status was more likely for third molars at cervical or apical level than at occlusal level: odds ratio was 10.1 for all teeth, 8.5 for maxillary teeth, and 6.2 for mandibular teeth. CONCLUSION: A third molar situated deeper in the bone was more likely to be disease-free than a tooth at occlusal level in the population aged 30 years and older. CLINICAL RELEVANCE: Our results suggest that the number of disease-free third molars decreased with increasing age, and most dramatically, this occurred among teeth at cervical level with the neighboring second molar.

Distance between mandibular canal and third molar root among 20-year-old subjects.

OBJECTIVES: The aim of the study was to evaluate the proximity of the mandibular third molar (M3) and the inferior alveolar canal (IAC) in a panoramic radiograph of 20-year-old subjects. The specific aim was to assess differences in this proximity over time. MATERIALS AND METHODS: Two similar samples of panoramic radiographs taken in a routine oral health examination with 20-year time interval were examined retrospectively and images with both mandibular M3s were included. The material consisted of 300 subjects (25% men, mean age 20.5 ± 0.6 years). The radiographic relationship between the mandibular M3 root and the IAC was assessed as follows: the M3 root was either apart from, tangential to, superimposed with, or inferior to the IAC. Differences between frequencies were tested using the chi-squared test. RESULTS: In the combined samples, only 16% of the M3s located apart from the IAC, 15% located tangential to, 61% superimposed with, and 8% inferior to the IAC. The proportion of the intimate locations had increased during the 20-year time interval from 79 to 88% (P < 0.01) and especially in females (P < 0.05). CONCLUSION: The vast majority of the mandibular M3s situated very close to the mandibular canal. CLINICAL RELEVANCE: Our results suggest that in the cohort of 20-year-old non-extraction subjects, most of the M3s are possibly at risk for inferior alveolar nerve injury at removal, as judged from the panoramic radiograph, and also the number of such teeth has increased over the 20-year period.

Malpractice claims related to tooth extractions.

OBJECTIVE: The aim of this study was to analyze malpractice claims related to tooth extractions in order to identify areas requiring emphasis and eventually to reduce the number of complications. MATERIAL AND METHODS: We compiled a file of all malpractice claims related to tooth extractions (EBA code) between 1997 and 2010 from the Finnish Patient Insurance Centre. We then examined the data with respect to date, tooth, surgery, injury diagnosis, and the authority's decision on the case. RESULTS: The material consisted of 852 completed patient cases. Most of the teeth were third molars (66 %), followed by first molars (8 %), and second molars (7 %). The majority of claims were related to operative extraction (71 %) followed by ordinary extraction (17 %) and apicoectomy of a single-rooted tooth (7 %) or multi-rooted tooth (2 %). The most common diagnosis was injury of the lingual or inferior alveolar nerve. According to the authority's decision, the patient received compensation more often in cases involving a third molar than other teeth (56 vs. 46 %, P < 0.05). CONCLUSION: The removal of a mandibular third molar was the basis for the majority of malpractice claims. CLINICAL RELEVANCE: To reduce the numbers of lingual and inferior alveolar nerve injuries, the removal of mandibular third molars necessitates recent and high-quality panoramic radiograph, preoperative assessment of the difficulty of removal, and consciousness of the variable anatomical course of the lingual nerve.

Pathology related to third molars in the elderly persons.

OBJECTIVES: The objective of this study was to clarify the discrepancy of pathology between earlier and recent studies related to third molars in the elderly persons. Evidence of third molars in the elders is limited. Earlier radiographic studies show rather few pathologic findings related to third molars. Recently, clinical studies have shown totally different numbers for pathology. MATERIALS AND METHODS: Participants were drawn from the population-based Helsinki Aging Study. The study included panoramic radiographs of 293 persons (mean age 79 years, SD ± 3.9 years). We examined the prevalence of third molars and associated pathology and used the chi-squared test to perform the statistical analysis. RESULTS: Of the whole group of elderly persons, 19% had at least one third molar. The usual dental diseases, caries and periodontal pathology (80 and 33%, respectively), were common in the third molars. The surviving third molar most often appeared in the mandible (P < 0.01), in men (P < 0.05), in the mesioangular position (P < 0.05), and far from the mandibular canal (P < 0.001). Pathology was present in every third molar, although the proportion of serious pathology (i.e., cyst and tumor), accounted for only 2% of third molars. CONCLUSIONS: Although serious pathology related to third molars in the elders is uncommon, universal biofilm diseases (caries and periodontal pathology) widely affect third molars as well as all other teeth. CLINICAL RELEVANCE: Because all of the surviving third molars of the elders were diseased, it would be justifiable to extract these teeth at a younger age.

Availability of CBCT and iatrogenic alveolar nerve injuries.

OBJECTIVE: To examine whether the rapid increase in the availability of cone-beam computed tomography (CBCT) has changed the number of inferior alveolar nerve (IAN) injuries related to the removal of mandibular third molars in Finland. The hypothesis was that the number of nerve injuries should diminish due to better imaging methods. MATERIALS AND METHODS: The number of CBCT devices, the annual number of CBCT examinations and the number of permanent IAN injuries occurring between 1997 and 2007 were analyzed. The data was collected from three national registers: the Radiation and Nuclear Safety Authority, the Social Insurance Institution and the Patient Insurance Centre. A detailed analysis was made from the cases of permanent IAN injuries. RESULTS: The first CBCT device was registered in 2002 and the cumulative number of these devices in 2009 was 22. There was an increase from 555 to 3160 in the number of annual CBCT examinations during the period 2004-2009. The total number of permanent IAN injuries during the years 1997-2007 was 129 and remained stable throughout the period (regression analysis, p = 0.974, r (2) = 0.01). CONCLUSIONS: Contrary to this hypothesis, the availability of CBCT devices has had no significant influence on the number of IAN injuries related to mandibular third molar removals in Finland. More education should be given to optimize the use of CBCT to cover difficult cases that may give rise to complications.

How often do asymptomatic, disease-free third molars need to be removed?

The preventive removal of third molars (M3s) should be based on evidence. To optimize the timing of removal of M3s, it is essential to predict the eruption of the tooth and, even more importantly, to recognize beforehand which teeth will become involved in pathologic conditions later in life. The first aim of this review was to determine how well physicians currently can predict the eruption of an M3. The second aim was to review how frequently impacted M3s are removed. The third aim was to summarize the indications for preventive removals as presented in the evidence-based Current Care Guideline for the management of M3s in Finland. The prediction of eruption can be made at accuracies from 80% to 97%. In addition, the decrease in the number of M3s is very rapid, with only 31% remaining at 38 years of age. According to the Current Care Guideline, preventive removals at a young age are justified for 3 groups of teeth in the mandible: partially impacted teeth in the horizontal position, partially erupted teeth in the vertical position, and incomplete roots growing close to the mandibular canal. In conclusion, one fourth of retained and disease-free M3s need to be removed preventively at a young age, whereas the rest should be treated according to signs and symptoms.

Reliability of CBCT and other radiographic methods in preoperative evaluation of lower third molars.

OBJECTIVES: The aim of this study was to compare the reliability of cone-beam computerized tomography (CBCT) with that of other radiographic methods in preoperative radiographic determination of the number of roots of lower third molars and their relationship to the inferior alveolar canal (IAC). STUDY DESIGN: Forty-two teeth were clinically studied and imaged using CBCT and other imaging methods-panoramic radiography, multiprojection narrow-beam radiography (MNBR), and cross-sectional tomography. Statistical analysis (kappa values) was used to compare the diagnoses of 2 trained oral radiologists and the radiologic diagnoses with the findings at operation. RESULTS: Cone-beam CT revealed the number of roots of teeth more reliably than panoramic radiographs. CBCT examination was highly reliable in locating the IAC, whereas MNBR was unreliable and cross-sectional tomography fell between the two. With cross-sectional tomography, the IAC was noninterpretable in one-third of the cases. CONCLUSIONS: We recommend CBCT examination for preoperative radiographic evaluation of complicated impacted lower third molars.

Dental and oral radiographic findings in first-year university students in 1982 and 2002 in Helsinki, Finland.

OBJECTIVE: This study is part of a larger research program, at the Finnish Student Health Service in Helsinki, in which changes in the dental and oral health of first-year university students (born in Helsinki) in the years 1982 and 2002 were compared. MATERIAL AND METHODS: Panoramic radiographs were taken of 176 students in 1982, mean age 19.8 years (SD+/-0.7), and of 231 in 2002, mean age 20.2 (SD+/-0.7). DMFT index, caries and periapical changes, alveolar bone resorption, wisdom teeth, supernumerary, missing, and persisting deciduous teeth were evaluated from the radiographs. The chi-squared test and non-parametric tests were used to analyze the statistical significance of differences between the study groups and between genders. RESULTS: The DMFT index diminished from 11.0 (SD +/- 4.2) to 2.9 (SD +/- 3.3) (p < 0.0001). In 2002, 27.9% of the students had a DMFT index of zero (in 1982, 0%, p < 0.000). The mean number of endodontically treated teeth diminished from 0.1 to 0.03 (p < 0.05). The number of impacted wisdom teeth increased in males from mean 0.41 to 0.69 (p < 0.05). CONCLUSIONS: An improvement in dental health was obvious in the year 2002. The favorable change in DMFT index is a trend that has been going on for several decades in Finland, probably as a result of the use of fluorides and better education in dental hygiene. The change might also be connected with improved general health.

Oral piercings among first-year university students.

OBJECTIVE: The aim of the study was to examine oral piercings among first-year university students. STUDY DESIGN: First-year university students in 2002 were invited to a dental examination (n = 234; 49 men and 185 women). Students with piercings formed the study group and the rest served as controls. The methods included decayed, missing, and filled teeth (DMF) index, stimulated salivary flow rates, panoramic tomograms, and questionnaires including the Depression Inventory of Beck. Fisher's 2-sided exact test was used for statistical analysis. RESULTS: The prevalence of oral piercings was 3.4%. In the DMF indices, no statistically significant differences existed between the groups. Increased salivary flow rates were noted among students with piercings (63% vs 26%, P < .05). Use of tobacco and illicit drugs, and also depression, were more prevalent in the study group than in the controls. CONCLUSION: Because of the possibility of oral implications, follow-up of oral piercings is essential.