Are women more susceptible than men to iatrogenic inferior alveolar nerve injury in dental implant surgery?

An over-representation of women in dental implant-related inferior alveolar nerve injuries (IANIs) is recognized in the literature but has not been investigated. Therefore, a nationwide retrospective register study was conducted to analyse how IANIs compare with other implant-related complications (infection, implant malposition, lack of bone at implant site, mechanical damage, or failed osseointegration) separately in women and men. Financially compensated malpractice claims related to dental implant surgery were collected from the Finnish Patient Insurance Centre for the years 1997-2013, while the total number of nationally placed implants was ascertained from the implant register held by the Finnish Institute for Health and Welfare. In the 242 complications, the following were analysed: age of subject, absolute risk for complication, and aetiological factor of IANI. Statistical tests applied include Mann-Whitney U-test, Chi-squared test, and Fisher's exact test. Women sustaining IANI were more likely older than those having infection, mechanical damage, or failed osseointegration (P<0.05), while no significant differences emerged in men. Women were more likely at risk for IANI (P<0.01) or implant malposition (P<0.05) than men. The results support earlier propositions that women are more vulnerable than men to iatrogenic IANI.

Age of patient at the extraction of the third molar.

The purpose of this study was to assess the age of patients at the time of extraction of third molars. Our data included all routine and surgical extractions of third molars (n=8199 teeth) performed by general and specialist dentists of the public oral health services of the city of Helsinki over the period 2013-2014. Measurements included patient's age, gender, the identified third molar, the type of anaesthesia, the method of extraction, and the diagnosis at extraction. Patients' ages ranged from 10 to 99years. We found significant differences between younger and older age groups: third molar extractions occurred more often for women than for men below the age of 30years (P<0.001) and vice versa for patients older than 30. Extractions were more prevalent for the upper jaw (P<0.001), and surgical extractions were more common than routine extractions (P<0.001) below the age of 40years, but the corresponding prevalences reversed after the age of 40years. Diagnoses at extraction differed between younger and older patients. We conclude that the treatment pattern of third molars at public health services varies greatly over a lifetime, and that a greater variety exists than had been reported previously from oral and maxillofacial units.

Signs of disease occur in the majority of third molars in an adult population.

The purpose of this study was to assess clinical and radiographic signs of disease in third molars within a population that is representative of the Finnish adult population aged 30 years and older. A two-stage stratified cluster sampling method was used to collect the 6005 subjects, who were examined clinically and also by panoramic radiography. The state of impaction, presence of dentinal caries and/or restorations, presence of root canal fillings, periodontal pocket depth, and additional pathological findings such as over-eruption and widened follicle were assessed. Signs of disease in the third molars were found in 47% of the adult population and in 97% of those subjects with third molars. At least one sign of disease occurred in 82% of erupted third molars compared to 74% of those impacted in soft tissue and 33% impacted in bone (P<0.001). A diseased third molar was more often located in the mandible (60%) than in the maxilla (40%) (P<0.001), and was more often found in men (57%) than in women (43%) (P<0.05). It is concluded that signs of disease in third molars in the target population are more common than has been reported previously.

Role of TNF-alpha and its receptors in pericoronitis.

The classic stimulus for cellular cytokine production is bacterial lipopolysaccharide (endotoxin). It was therefore hypothesized that tumor necrosis factor-alpha (TNF-alpha) may be responsible for pericoronitis. TNF-alpha and its receptors were detected by immunohistochemical staining in third molar pericoronitis in ten patients and ten healthy control samples. The percentage of TNF-alpha positive cells was high in pericoronitis (p = 0.0317). TNF receptors TNF-R1 and TNF-R2 were found in macrophage- and fibroblast-like cells, vascular endothelial cells in post-capillary venules, and basal epithelial cells in pericoronitis, but were only weakly expressed in controls. Increased expression of interleukin-1beta and vascular cell adhesion molecule-1 was found as a biological indicator of TNF-alpha ligand-receptor interaction. Explanted tissues acquired destructive potential upon TNF-alpha stimulation, whereas TNF-alpha blockers controlled it in inflamed tissues. These findings suggest that, in pericoronitis, inflammatory and resident cells produce and respond to potent pro-inflammatory cytokine TNF-alpha, with pathogenic and potential therapeutic relevance.

Application of the Third Molar Eruption Predictor to periapical radiographs.

The aim of this study was to test whether the Third Molar Eruption Predictor, developed for panoramic radiographs, can also be applied to periapical radiographs. The Third Molar Eruption Predictor is a transparent device (US patent 5,816,814), not commercially available, and developed for prediction of future eruption or impaction of third molars. The material consisted of periapical radiographs of mandibular third molars taken from the lateral projection without angulation of the central beam. The radiographs taken at the mean age of 20.6 years (SD +/- 1.4 years) were retrospectively available from a four-year follow-up study of third molars carried out at the University of Copenhagen, Denmark. Initially unerupted or partially erupted third molars (n=43) in 28 dental students were analyzed. Clinical statuses of the third molars were available at baseline and four years later. The device was calibrated using the method of simple proportions and Bayes' Decision Theory. The predictions made with the calibrated device were in conformity with the final clinical outcome in 84% of the cases. It was concluded that the Third Molar Eruption Predictor may also be used on periapical radiographs after calibration of the device.

Accuracy of the Third Molar Eruption Predictor in predicting eruption.

OBJECTIVE: To evaluate the possibility of applying the Third Molar Eruption Predictor to all panoramic radiographs. STUDY DESIGN: Panoramic radiographs were retrospectively analyzed from a 4-year follow-up study of third molars carried out at the University of Copenhagen, Denmark. The radiographs, taken at a mean age of 20.6 years, included 45 unerupted or partially erupted mandibular third molars in 28 subjects. Because the device was calibrated both with simple proportions and by use of the methods of Bayes' Decision Theory, the separation point of the device was therefore adjusted at 12 mm from the distal surface of the second molar. RESULTS: The predictions of future eruption or impaction made with the calibrated device and the actual clinical outcome 4 years later were in conformity for 80% of the mandibular third molars. CONCLUSION: The Third Molar Eruption Predictor may be applied to all panoramic radiographs, but it seems to require calibration before use.

Radiographic follow-up of impacted third molars from age 20 to 32 years.

Nineteen patients (13 male, six female) with 34 impacted third molars, 21 in the mandible and 13 in the maxilla were radiographically followed from age 20 to 32. All were examined clinically and panoramic radiographs were taken at baseline and at the end of the study. Radiographic analysis included resorption of teeth, enlargement of the follicle, development of the root, change in inclination of the third molar, state of impaction, relative depth of the third molar in bone and relation to the ramus of the mandible and to the second molar tooth. In the mandible, the mean change in inclination was 19 degrees and the percentage of teeth with changed angulation was 76%. In the maxilla, only 23% of the teeth changed their inclination. The state of impaction (soft tissue, partially in bone, completely in bone) had changed for 44% of the teeth. According to the questionnaire, no pain or symptoms in the region of the third molars were reported by 74% of the students during the 12-year period. It is concluded that considerable radiographic changes, without notable symptoms, may occur involving inclination of the tooth and state of impaction in impacted third molars after the usual age of eruption.

Thermographic imaging of postoperative inflammation modified by anti-inflammatory pretreatment.

PURPOSE: The aim of this study was to assess the usefulness of thermography in detecting the postoperative inflammatory reaction after third molar removal. PATIENTS AND METHODS: Thermographic images (NovaTherm; Novamedix Ltd, Hampshire, England) of both cheeks were obtained on the first and seventh postoperative days after removal of impacted mandibular third molars under local anesthesia in 30 patients (15 men, 15 women). The unoperated contralateral side served as a control. One of the following pretreatments was given immediately before the operation: diclofenac (Voltaren; Novartis, Espoo, Finland) 150 mg orally (rapid-release 50 mg and prolonged-release 100 mg, n = 15), diclofenac 100 mg orally (prolonged-release) and 50 mg intramuscularly (n = 11), or placebo (n = 4). RESULTS: The postoperative skin surface temperature on the operated side was significantly higher than that on the unoperated side. The thermal difference was 0.9 degrees C +/- 0.1 degrees C on the first postoperative day and declined significantly by the seventh day to 0.3 degrees C +/- 0.1 degrees C (both P < .001). The thermal difference in patients receiving diclofenac preoperatively was significantly smaller (0.8 degrees C +/- 0.1 degrees C at day 1 and 0.2 degrees C +/- 0.1 degrees C at day 7) than in patients receiving placebo (1.6 degrees C +/- 0.1 degrees C at day 1 and 0.8 degrees C +/- 0.3 degrees C at day 7, P < .001). However, with equal doses of diclofenac, the combination of rapid-release and prolonged-release tablets orally was more effective in reducing skin temperature than an orally administered prolonged-release tablet combined with intramuscular injection (P < .001). CONCLUSION: Thermography is a suitable method to measure the inflammatory reaction related to third molar removal. Thermal changes are significant and are decreased by the nonsteroidal anti-inflammatory drug diclofenac.

Long-term evaluation of estimates of need for third molar removal.

PURPOSE: The aim of this study was to evaluate the estimates on need for third molar removals made at age 20 after 12 years. PATIENTS AND METHODS: The series consisted of 81 university students followed from age 20 to 32 years. At baseline and at study end, these students were clinically examined, and panoramic radiographs were taken. At baseline in 1982, a qualified oral surgeon had made estimates on need for removal of third molars within 5 years; 75% of students needed removals. Actual treatment performed was evaluated after 12 years. A questionnaire served to determine symptoms related to third molars during the 12-year period. RESULTS: During the follow-up, one or more third molars had been removed from 67% of the former students. A total of 155 third molar removals had been estimated, but by age 32 years the percentage actually removed was only 59%. Of the 79 third molars taken out at the Finnish Student Health Service, 77% were initially estimated to need a surgical procedure, but actually 66% were simply extracted. Most were removed at around age 27 years. According to the questionnaire, 67% of the students were asymptomatic in the third molar region during 12 years. CONCLUSION: Because need for surgical removal decreases during early adulthood, routine prophylactic extraction of asymptomatic third molars in young adults cannot be recommended. Well-defined indications for prophylactic removals are needed.

Change in clinical status of third molars in adults during 12 years of observation.

PURPOSE: The aim of the study was to follow the clinical changes in third molar status during a 12-year period in patients aged 20 to 32 years. PATIENTS AND METHODS: The study was based on a follow-up of 81 university students (32 men, 49 women). They were clinically examined and panoramic radiographs were taken at baseline (mean age, 20.7+/-0.5 years) and at the end of the study (mean age, 32.6+/-0.6 years). RESULTS: The students had 285 unerupted, partially erupted, or fully erupted third molars at the beginning of the study, and 150 at the end. On final examination, 115 teeth were erupted. During the first 6 years from age 20 to 26, various clinical changes took place in the status of the third molars. In the second 6 years, until age 32, the two main changes were either removal or eruption. During the 12-year follow-up, 22% of third molars erupted, a few even after 26 years of age; the percentage of third molars removed was 42%. CONCLUSION: Third molars undergo continuous clinical change at least up to the age of 32 years.

Malpractice claims for permanent nerve injuries related to third molar removals.

On the basis of the register of the Finnish Patient Insurance Association, the aim of this study was to examine malpractice claims for nerve injuries associated with third molar removals and determine whether they are concentrated among specialists, among less experienced dentists, or in certain geographic areas. During 1987-93 there were 139 claims for permanent sensory or motor disturbances related to removal of lower third molars in Finland. The lingual nerve was injured in 54% and the inferior alveolar nerve in 41% of the claims. In 91% of the cases the injury occurred in relation to surgical removal of the tooth and in 6% in relation to simple extraction. The claims were distributed among 123 dentists, of whom 78% were dental surgeons, 15% specialists in oral and maxillofacial surgery, and 7% other specialists. These figures represented 2% of the dental surgeons and 26% of the oral surgeons in Finland (P< 0.01). More than half the claims were associated with dentists with less than 10 years' experience. Claims originated more often from the eastern and northern (rural) areas of Finland than from urban areas (3.8 claims versus 2.4 claims per 100,000 inhabitants, P < 0.05). Compensation was paid to the patients in two-thirds of the cases, indicating that the dentists authorized to decide claims very often considered these injuries avoidable. Therefore, proper diagnosis, treatment planning, surgical techniques, and detailed patient information must be emphasized. In cases where risks are obvious, referral to an oral surgeon is recommended.

Factors predisposing to postoperative complications related to wisdom tooth surgery among university students.

In a retrospective study among 550 Helsinki University students 20 to 30 years old, factors predisposing to postoperative complications from removal of lower jaw wisdom teeth were evaluated. Patient records and panoramic tomograms covering the period from 1990 to 1993 were examined; 50 patients (9.1%) had postoperative complications after removal of a wisdom tooth. The most common complications were alveolar osteitis (2.9%), postoperative infection (2.6%), postoperative bleeding (1.5%), and dysesthesia of the lower lip or tongue (1.1%). Factors associated with increased postoperative complications were mesiohorizontal position of the tooth, deep impaction of the tooth, and use of oral contraceptives. Before patients undergo surgery for removal of wisdom teeth, those who use oral contraceptives or have difficult tooth impactions should be informed about the increased possibility of postoperative complications.

A device to predict lower third molar eruption.

This study was designed to create a transparent device to be superimposed on a panoramic tomogram taken of a patient at age 20 years to make predictions of future eruption or impaction of lower third molars. The device was developed from data on 40 lower third molars initially retained at age 20 years; one half of these remained impacted, and the other half of them erupted by age 26 years. Tracings were made from panoramic tomograms taken at age 20 years. The critical point for prediction in the overlay was the intersection of a horizontal reference line and the anterior border of the ascending ramus. To estimate this critical separation line, Bayes' Decision Theory was used. The sum of false negatives and false positives was least at a distance of 14.5 mm from the distal surface of the second molar. Mesial from this point, the probability of impaction was 76%; distal from this point, the probability of eruption was 72%. Tested against 35 initially unerupted lower third molars, the predictions made by the device and the actual clinical findings were in conformity in relation to 97% of the test teeth. It could thus be concluded that the method was simple to use and may prove a good addition for predicting lower third molar development.

Predictive model for impaction of lower third molars.

The study was carried out to create and test a model for predicting impaction of lower third molars on the basis of radiographic findings at age 20 years. Fifty-six initially unerupted lower third molars were followed up for 6 years. Five radiographic findings in panoramic tomograms at age 20 were taken as variables. Clinical status at age 26 was taken as response. The radiographic features studied were angulation of tooth, development of root, state of impaction, depth in bone, and relation of the tooth to the ramus of the mandible and the second molar. With the use of logistic regression, univariate and bivariate analyses, and clustering techniques, a decision tree was constructed that indicated accuracies of prediction on the basis of single variables or pairs of variables. The most important predictor was the type of impaction. The model predictions and test teeth findings were in agreement in 94% of instances. It was concluded that the model is suitable for predicting lower third molar impaction at age 20.

Third molars as an acute problem in Finnish university students.

The study was carried out to determine the risk of acute disease of third molars in young adult patients. The subjects in this case-control study were 100 consecutive university students who complained of third molar problems when making an appointment. The third molars were mostly mandibular, partly erupted, and distoangularly oriented. Severity of discomfort and interference with daily activities were graded by the patients on average as 5.0 (SD +/- 2.7) and 3.6 (SD +/- 2.9), on a scale from 0 through 10. Distoangular lower third molars caused the most discomfort and interfered most with activities of patients. The risk of acute disease in patients with distoangularly oriented third molars was 3.6 times that in other patients. Bivariate analysis showed that if the follicle of a distoangular third molar were enlarged, the risk of acquiring acute disease was 44 times that in other patients. It was concluded that early removal of partially erupted and distoangularly oriented lower third molars is recommended, especially when they are associated with an enlarged follicle.

Third molars confusing the diagnosis of carcinoma.

The purpose of this study was to describe cases of oral cancer in which the initial presenting symptoms were considered to be due to third molars and in which the underlying carcinoma therefore escaped early diagnosis. Between 1986 and 1990 a total of five cases with squamous cell carcinoma associated with a third molar (impacted, partially or totally erupted, or recently extracted) were treated at our unit. Because of acute or chronic symptoms related to disturbed eruption of third molars, the detection of a simultaneous malignant change and referral were delayed. In conclusion, all third molars, especially impacted, partially erupted, or overerupted ones, should be examined critically, especially if the patient has symptoms.

Effect of erupting third molars on dental caries and gingival health in Finnish students.

The purpose of this study was to assess how the eruptive status of third molars relates to gingival and dental health and, in particular, to the status of the adjacent second molar. One hundred and twenty-three young adults were followed up over a 6-year period, from age 20 to age 26. The status of the second and third molars, and DMF, DMFS, DS, MS, and FS indices, periodontal condition, and salivary acidogenic bacterial counts were assessed. The 6-year DFS increase in relation to second molars was greatest in sextants with unerupted third molars. The percentage of erupting third molars that became carious or had been filled during the study period was 30%. Most new caries lesions or filled surfaces were on mesial surfaces of second molars and occlusal surfaces of third molars. The periodontal condition was best in mandibular sextants in which the third molar was missing. It is concluded that the most favourable situation for upper second molars is if the neighbouring third molar is missing by age 20.

Use of dental services by students of Helsinki University during six years.

This follow-up study was carried out to survey the utilization of dental services among university students, together with treatment modalities received during their six years of university studies. Initially 20-year-old students were followed during six years, starting from their first year at the University of Helsinki. Results of the questionnaire showed that during the previous 12 months 59% of the students had had a dental appointment, mostly on their own initiative. According to the patient register, 83% of the students, during their studies, had received dental care financially subsidized at the Finnish Student Health Service (FSHS) in Helsinki. During the six years of follow-up, the mean number of appointments was 9.3 per patient (SD 6.8). Female students made dental appointments relatively more often than did male students (p < 0.01). The main treatment modality was restorative care. Patients did not show up for 3.5% of all appointments reserved. One sixth of all visits were made by a group representing 5% of the study group. In conclusion, as the utilization of FSHS dental services was very common, and as restorative dentistry continues to be the main treatment modality among Finnish university students, prophylaxis of caries in systematic dental health care programmes at FSHS is of prime importance and thus has a good possibility to reach each student.

Assessing the eruption of lower third molars on the basis of radiographic features.

To determine radiographic features by which one could estimate whether lower third molars are likely to erupt after the age of 20 years, university students with a total of 84 unerupted or partially erupted lower third molars were followed up. Five radiographic features of each third molar were measured from the panoramic tomogram taken at age 20 years, and the status of third molars was examined for a second time at age 26 years. The results showed that the lower third molars that did erupt after the age of 20 years were initially: 1) root formation complete; 2) impacted in soft tissue; 3) vertical; 4) placed at the same occlusal level as the neighbouring second molar; 5) showed sufficient space between the ramus and the second molar. In contrast, the teeth that remained impacted at the age of 26 years showed such initial features as: 1) incomplete root formation; 2) embedding in bone; 3) mesioangularity; 4) situated at the cervical level of the neighbouring second molar. It was concluded that a panoramic tomogram taken at age 20 years revealed radiographic features on which an estimation of future eruption of mandibular third molars could be based.