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At least 397 records · Page 22Linked to original sources
PubMed2006

Pathology associated with impacted mandibular third molars in a group of Jordanians.

PURPOSE: The aim of this study was to determine the frequency and type of a group of radiographically detectable pathologic conditions around impacted mandibular third molars in Jordanians. PATIENTS AND METHODS: A retrospective study of patients referred to the Oral and Maxillofacial Surgery unit for surgical removal of impacted mandibular molars. The analysis outcome measures were the patients' age and gender, and any radiographic lesions associated with the impacted mandibular third molars. The following radiographic lesions were recorded in relation to the impacted third molar: caries, pericoronal radiolucent areas, and periapical radiolucent areas, in addition to odontomes, caries in the adjacent second molars, and external resorption of the roots of adjacent mandibular second molars. Bony radiolucent areas were all verified histopathologically. RESULTS: Impacted mandibular third molars (N = 2,432) from 1,398 patients were examined; 46.4% of third molars showed associated radiographically detected lesions. The most common lesion seen on panoramic radiographs was dental caries. Others included pericoronal radiolucent and periapical radiolucent areas. The majority of periapical radiolucent areas were histologically proven to be chronic periapical inflammation. All pericoronal radiolucent areas were histologically found to be either cysts or tumors. The most common cyst was dentigerous cyst; the most common tumor was ameloblastoma. CONCLUSION: A high ratio of impacted mandibular third molars in this group of Jordanians had an associated pathologic lesion.

Adolescent↗
PubMed1998

UK National Third Molar project: the initial report.

The National Third Molar (NTM) project was set up to assess current clinical practice in the UK concerning the management of third molar teeth. Patients were recruited from both hospital and general dental practice. During the one month study period 9248 patients with 26,577 third molars were recruited. In this report we present the findings in the 8298 patients with 25,001 third molars who were referred to hospital for assessment. Over half of all patients referred for assessment had either no extractions or a single third molar extracted. Less than a quarter of all patients referred underwent removal of all four third molars. Twenty per cent of all third molars assessed were not extracted. Of all lower third molars listed for extraction, 9574 (78%) were associated with symptoms or disease. Pericoronitis was the commonest indication for extraction and was cited in 39.5% of all extractions. Almost 70% of third molar extractions were done under general anaesthesia while less than a quarter were performed under local anaesthesia alone.

Adult↗
PubMed2002

Dental age estimation and third molars: a preliminary study.

The aim of the present investigation was to reconstruct the chronological age based on the dental developmental stages of third molars evaluated on orthopantomograms. A total of 1175 orthopantomograms were assembled from patients of Caucasian origin between 16 and 22 years of age. Each third molar present was scored by two observers according to a 10-stage developmental scale. The kappa statistics measured the intra- and inter-observer reliability. The general statistical analysis was based on multiple regression analysis in order to obtain multiple regression formulas for dental age estimation based on the number of third molars present on the evaluated orthopantomogram. No regression models were statistically significant when there was only one-third molar present because of the relatively small number of orthopantomograms that fitted this criterion. A strong agreement was found between the intra- and inter-observer measurements. The statistical analysis revealed both for males and females high Pearson correlation coefficients between contralateral third molars and smaller coefficients between antimeres. The obtained multiple regression formulas are only applicable in certain specified conditions, for instance when four third molars are present the following formulas should be used in a Caucasian male "age=10.2000+0.5122UL+0.5273LL" (developmental stage of upper and lower left third molars) or in case of a female "age=13.6206+0.1933UR+0.5080LR" (developmental stage of upper and lower right third molars). This investigation revealed that the chronological age of a Caucasian individual may be estimated based on regression formulas with a S.D. of 1.52 or 1.56 years for males and females, respectively, when all four third molars are present.

Adolescent↗
PubMed2003

Transverse molar movements during growth.

The purpose of this study was to evaluate changes in molar crown torque and intermolar arch width from the time of permanent first molar eruption to early adulthood. Molar crown torque and intermolar arch width were measured in 36 untreated subjects with Class I occlusion from the Iowa Facial Growth Study at approximate ages 7.5, 10.3, 12.9, 16.5, and 26.4 years. On average, the mandibular first and second molars uprighted buccally by 5.0 degrees and 7.5 degrees, respectively. Mandibular first and second molar intermolar width increased by 2.2 and 0.78 mm, respectively. On average, maxillary first and second molars uprighted lingually by 3.3 degrees and 5.9 degrees, respectively. Maxillary first and second intermolar width increased by 2.8 and 2.0 mm, respectively. Results of statistical analysis by the Wilcoxon signed rank test indicate that (1) maxillary molars erupt with buccal crown torque and upright with age, whereas mandibular molars erupt with lingual crown torque and upright with age (P <.01), and (2) molar crown torque changes are accompanied by concurrent increases in maxillary and mandibular intermolar width (P <.01).

Adolescent↗
PubMed1996

Prediction of coronal size of third molars by factor and multiple regression analyses.

Factor analysis and multiple regression analysis were made to establish a method for the prediction of the unerupted third molar size. The samples were dental casts of 138 adults (69 women and 69 men) who had all their teeth from the central incisor to the third molar, at least in one side of each maxillary and mandibular dentition. Mesiodistal and buccolingual tooth crown sizes were measured with sliding calipers. Five factors were selected from the factor analysis on the tooth crown sizes. Multiple regression analysis with the third molar as the dependent variable was carried out. Independent variables were selected on the basis of the factors obtained from the factor analysis. Two kinds of multiple regression equations were obtained (the first molar was used as an independent variable in one equation and the second molar was used in the other). The accuracy of the prediction was highest when the lateral incisor, the second premolar, and the second molar were used as independent variables in the maxillary dentition, and the central incisor, the first premolar, and the second molar in the mandibular dentition. The mean of the absolute values of the differences between the predicted values and the actual values was 0.5 mm in the maxillary third molar, and 0.42 mm in the mandibular third molar.

Adult↗
PubMed1996

Reconstruction of alveolar bone defects after extraction of mandibular third molars: a pilot study.

INTRODUCTION: A documented complication of mandibular third molar extraction is the development of bony defects on the distal aspect of the adjacent second molar. The primary study purpose was to determine the efficacy of grafting third molar extraction sites with demineralized bone powder to prevent the formation of periodontal defects. MATERIAL/METHODS: With a randomized clinical trial study design and a third molar extraction surgical model, we enrolled a study sample composed of patients who required extraction of bilateral third molars. Demineralized bone powder was placed in one randomly selected extraction site per patient. The remaining extraction site served as a control. Patients served as their own controls. To assess periodontal healing, we measured plaque and gingival indexes and periodontal attachment loss on the distobuccal aspect of the adjacent second molar preoperatively and 6 months postoperatively. RESULTS: Of 14 patients enrolled, 7 patients with a mean age of 21.7 +/- 3.7 years completed the study protocol. No statistically significant differences were noted between patients who did and did not complete the study protocol (all p values > or = 0.42). There were noted statistically significant differences for the various anatomic, operative, or periodontal measures between the control and treatment teeth preoperatively (all p values > or = 0.46). Six months postoperatively, there were no statistically significant changes in the plaque or gingival indexes for the control or experimental sites. At the control sites, there was a nonstatistically significant decrease in mean attachment loss from 3.1 +/- 1.3 mm preoperatively to 1.4 +/- 1.6 mm 6 months postoperatively (p = 0.06). At experimental sites, there was a statistically significant decrease in mean attachment loss from 3.3 +/- 1.4 mm preoperatively to 0.6 +/- 0.8 mm 6 months postoperatively (p = 0.02) CONCLUSIONS: The study results suggest that demineralized bone powder may decrease attachment loss on the distal aspect of the second molar after extraction of the adjacent third molar. Additional studies are indicated to confirm the results of this pilot study. We recommend that future studies limit their study samples to patients at high risk for developing periodontal defects after third molar extraction.

Adult↗
PubMed1992

Periodontal considerations in the use of bonds or bands on molars in adolescents and adults.

This longitudinal study compared the periodontal status of bonded and banded molars in 20 adult and 40 adolescent patients before, during and after treatment with fixed orthodontic appliances. Plaque accumulation (measured by the Plaque Index), gingival inflammation (measured by the Gingival Index and the bleeding tendency), and pocket depth were assessed by one examiner at sites along the mesio-buccal line angle of the maxillary right first molar and the mandibular left first molar. Assessments were made immediately prior to the placement of fixed appliances (pretreatment), at 1, 3, 6, 9, 12 and 18 months after appliances were placed; and 3 months after appliances were removed (posttreatment). Loss of attachment between the pretreatment and posttreatment visits also was determined. At pretreatment, no significant differences were found in gingival inflammation between maxillary and mandibular banded and bonded molars. During treatment, both maxillary and mandibular banded molars showed significantly (p less than 0.05) greater gingival inflammation and plaque accumulation than did bonded molars. Three months after appliance removal, the maxillary molars that had been banded continued to show significantly more gingival inflammation and loss of attachment than did the maxillary molars that had been bonded. When all banded and bonded teeth were grouped by patient age, mean values for plaque accumulation and gingival inflammation in the maxillary molar regions were significantly greater for adolescents than for adults.

Adolescent↗
PubMed2002

Relationship between congenitally missing lower third molars and late formation of tooth germs.

In this investigation, we used longitudinal panoramic radiographs from 96 subjects (47 boys, 49 girls) who did not have any congenital disease. The subjects were selected based on their age at the initial radiograph and the number and frequency of radiographs. Lower left premolars and second molars were used as parameters to identify factors that influence the age of formation of the third molar. We classified teeth into eight formation stages according to the method of Demirjian. The age at the beginning of formation of the lower third molar was determined with a regression equation of longitudinal data. The highest correlation existed between the age at the beginning of formation of the third molar and the formation stage of the second molar. We conclude that late formation of tooth germs is one of the factors that leads to the congenital absence of lower third molars. Furthermore, we assume that when the tooth germ of the lower third molar has not appeared at stage 7 of formation of the second molar, the probability of the third molar being missing is 100%.

Anodontia↗
PubMed2004

Intraosseous screw-supported upper molar distalization.

The aims of the present study were to investigate (1) the efficiency of intraosseous screws for anchorage in maxillary molar distalization and (2) the sagittal and vertical skeletal, dental, and soft tissue changes after maxillary molar distalization using intraosseous screw-supported anchorage. Twenty-five subjects (18 girls and seven boys; 11.3 to 16.5 years of age) with skeletal Class I, dental Class II malocclusion participated in the study. An anchorage unit was prepared for molar distalization by placing an intraosseous screw behind the incisive canal at a safe distance from the midpalatal suture following the palatal anatomy. The screws were placed and immediately loaded to distalize upper first molars or the second molars when they were present. The average distalization time to achieve an overcorrected Class I molar relationship was 4.6 months. The skeletal and dental changes were measured on cephalograms and dental casts obtained before and after the distalization. In the cephalograms, the upper first molars were tipped 8.8 degrees and moved 3.9 mm distally on average. On the dental casts, the mean distalization was five mm. The upper molars were rotated distopalatally. Mild protrusion (mean 0.5 mm) of the upper central incisors was also recorded. However, there was no change in overjet, overbite, or mandibular plane angle measurements. In conclusion, immediately loaded intraosseous screw-supported anchorage unit was successful in achieving sufficient molar distalization without major anchorage loss.

Adolescent↗
PubMed2005

Extraoral vs intraoral appliance for distal movement of maxillary first molars: a randomized controlled trial.

Using randomized controlled trial methodology, the aim of this study was to evaluate and compare the treatment effects of an extraoral appliance (EOA) and an intraoral appliance (IOA) for distal movement of maxillary first molars. A total of 40 patients (mean 11.5 years, SD 1.29) at the Orthodontic Clinic, National Health Service, Skane County Council, Malmö, Sweden, were randomized to receive treatment with either extraoral traction (cervical headgear) or an IOA using superelastic coils for distal movement of maxillary first molars. The inclusion criteria were a nonextraction treatment plan, a Class II molar relationship and maxillary first molars in occlusion with no erupted maxillary second molars. The outcome measures to be assessed in the trial were treatment time, cephalometric analysis of distal molar movement, anterior movement of maxillary central incisors, ie, anchorage loss and sagittal and vertical skeletal positional changes of the maxilla and mandible. In the IOA group, the molars were distalized during an average time of 5.2 months, whereas in the EOA group the corresponding time was 6.4 months (P < .01). The mean amount of distal molar movement was significantly higher in the IOA than in the EOA group, three mm vs 1.7 mm (P < .001). Moderate anchorage loss was produced with the IOA implying increased overjet (0.9 mm) whereas the EOA created decreased overjet (0.9 mm). It can be concluded that the IOA was more effective than the EOA to create distal movement of the maxillary first molars.

Cephalometry↗
PubMed1992

Distalization of maxillary first and second molars simultaneously with repelling magnets.

The aim of this study was to analyse the clinical and the dentofacial effects of using repelling SmCo5 magnets for distalization of maxillary first and second molars simultaneously. Ten consecutive patients, aged 12.0-15.6 years, with Class II malocclusion and moderate space deficiency in the upper jaw were orthodontically treated using prefabricated repelling SmCo5 magnets. The magnets were attached buccally in the premolar and first molar area to a fixed orthodontic applicance. When the magnets were activated, the molars could move freely distally. The tooth movements were analysed by measurements on dental casts, lateral photographs of dental casts, and lateral skull radiographs before and after treatment. The mean treatment time was 16.6 weeks and all maxillary molars could be distalized to a Class I relationship. The mean molar crown movement was 4.2 mm, and the maxillary first molars tipped distally and rotated disto-buccally by 8.0 and 8.5 degrees, respectively. The reciprocal forces resulted in a slightly increased inclination of the upper incisors. It was found that simultaneous distalization of first and second maxillary molars with repelling magnets could be an alternative to ordinary orthodontic treatment methods. As the molar distalization was achieved during a relatively short period, occlusal adjustment, including uprighting and derotation of the maxillary molars as well as post-treatment retention, seems recommendable.

Adolescent↗
PubMed1997

The effect of different etching times on the retention of fissure sealants in second primary and first permanent molars.

This study investigated the effect of different etching times on the retention of fissure sealants in second primary and first permanent molars. Eighty-four children with a total of 144 second primary molars and 264 first molars were included in the study. Etching times of 15, 30, 45 and 60 seconds were used. The fissure sealants were evaluated at 6 and 12 months. The results showed that the overall retention rate of fissure sealants in second primary molars was 73.0% at 6 months and 64.7% at 12 months, whereas in first permanent molars the retention rates were 60.7% at 6 months and 44.1% at 12 months respectively. There was no significant difference in the retention of fissure sealants either on second primary molars or on first permanent molars at a 6- and 12-month follow-up with the different etching times. It was concluded that the different etching times did not appear to affect the retention of fissure sealants on the first permanent molars or second primary molars. It might therefore be prudent to etch the teeth for a much shorter period than conventionally recommended.

Acid Etching, Dental↗
PubMed2000

The not-so-harmless maxillary primary first molar extraction.

BACKGROUND: Premature loss of primary molars has been associated with space loss and eruptive difficulties, especially when the loss occurs to the primary second molars and when it occurs early. This has not been thought to be the case for primary first molars. METHODS: The author revisited 13 cases from an earlier study on the effects of premature loss of maxillary primary molars. These longitudinal cases were scrutinized, using serial panoramic radiographs, to explain the irregular response in terms of dental migration. The author presents two case reports. RESULTS: In the earlier study, the author used digitized study casts and the concept of D + E space--the space occupied by the primary first and second molars--to describe the dental migration that occurred after premature tooth loss. Using analysis of variance on data generated using an instrument capable of measuring in tenths of millimeters, the author produced findings regarding the amount of space loss, rate of space loss, effect of age at loss, amount of space regained at the time of replacement by the permanent tooth and effect on Angle's classification. Finally, the author created a simulation describing directional change; this revealed that the maxillary primary first molar loss resulted in a mesial displacement of the permanent canine during eruption. CONCLUSIONS: When the maxillary primary first molar is lost prematurely, the first premolar erupts in a more mesial direction than normal, as a result of the mesial incline of the primary second molar, and consumes the space of the permanent canine, which becomes blocked out. CLINICAL IMPLICATIONS: Rather than use a space maintainer after the premature loss of the maxillary primary first molar, the author suggests, clinicians can choose from a number of other options for preventing the first premolar from erupting too far in a mesial direction.

Adolescent↗
PubMed2006

Third-molar extraction as a risk factor for temporomandibular disorder.

BACKGROUND: Although third-molar extraction is common in the U.S., there are few reports on the relationship between third-molar extraction and temporomandibular disorder (TMD). The aim of this study was to investigate this potential association. METHODS: The authors enrolled study subjects on their 15th birthdays and followed them continuously for a minimum of five years. The authors ascertained exposure (third-molar extraction) and outcome (TMD) via electronic dental insurance records. A survival analysis design estimated the relative risk of experiencing TMD after third-molar extraction. They considered sex, dental care utilization and other potentially confounding variables in the analyses. RESULTS: A total of 34,491 subjects met the inclusion criterion. Fifty percent of all subjects had third molars removed by the age of 20 years, and 391 subjects had claims indicating TMD. The adjusted relative risk of experiencing TMD after third-molar extraction was 1.6 (95 percent confidence interval, 1.3 to 2.0). Calculation of the population risk indicated that 23 percent of all TMD cases in this age group might be due to third-molar extraction. CONCLUSIONS: Third-molar extraction appears to be a risk factor for TMD. CLINICAL IMPLICATIONS: Dental providers should be aware of the risk of experiencing TMD related to third-molar extraction and take measures to minimize trauma to the joint during extraction.

Adolescent↗
PubMed1981

Root fusion in molars: incidence and sex linkage.

The study was done to determine the incidence and distribution of root fusion in 1340 maxillary and mandibular molars in 170 patients. A second objective was to determine whether root fusion of molars is sex-linked. A substantial percentage, 29% of all molars, had fused roots. Root fusion was found more frequently in maxillary than mandibular molars, 35% to 24%, and it occurred in many patients, rather than being limited to a few. Root fusion was most common in third molars, followed by second molars, in both jaws. It occurred in almost equal numbers in corresponding molars of opposite sides, approaching bilateral symmetry. The proportion of molars with root fusion was approximately 5% greater in females than in males, and about 13% more females had molar root fusion than males.

Adult↗
PubMed1999

Long-term evaluation of 282 implants in maxillary and mandibular molar positions: a prospective study.

BACKGROUND: Placement of implants into molar positions presents diagnostic, surgical and prosthetic challenges. There are few reported studies for implants placed into molar positions. The purpose of this prospective longitudinal study is to report long-term clinical outcomes for 282 implants placed into molar positions. METHODS: Two-hundred-twelve patients received 282 implants. Implant size, location, jaw shape, and bone quality were recorded for all implants placed into molar positions. Seventy implants were inserted in maxillae and 212 in mandibles. Marginal bone level changes in maxillae and mandibles were measured from non-standardized periapical radiographs taken at abutment connection and an average follow-up of 3.9 years. Mesial-distal implant measurements were made from the top of the implant cylinder to the first point of bone to implant contact. In mandibles, 39 implants were used for single molar replacements, 67 implants were placed into excellent bone quality (type I) and 113 were in good bone quality (type 11); 145 implants were placed into bone with moderate bone resorption (type B); 166 implants were placed in first molar positions and 46 in second molar sites. RESULTS: At 6 years the cumulative success rate (CSR) for mandibular implants is 91.5%, and the success rate from the 2 to 3 year follow-up is 100%. Of the 70 implants placed in maxillae, 16 replaced single molars. Thirty-two implants were placed in jaw shape B with type 2-bone quality. For maxillary implants, the 6-year CSR was 82.9% and the success rate remained steady at 100% after the 2 to 3 year follow-up. For maxillary implants, at abutment connection the average marginal bone level was 1.67 mm, while at follow-up it was 1.98 mm. These differences were statistically significant (P = 0.04), but are not considered to be clinically significant. For mandibular implants, at abutment connection the mean marginal bone level as measured from radiographs was 2.11 mm, and at follow-up was 2.02 mm. This slight gain in bone level was not statistically significant and is not considered to be clinically significant. CONCLUSIONS: Results of this prospective longitudinal study of implants placed into molar positions indicates favorable clinical outcomes. These CSR rates (91.5% mandibles, 82.9% maxillae) are less than what has been reported for implants placed into mandibular and maxillary anterior segments. Differences in outcomes between anterior and posterior locations may be related to bone quality and quantity.

Bone Density↗
PubMed1999

Studies on agenesis of third molars amongst populations of different origin.

This study contains information on the occurrence of agenesis of one to four third molars among the population and ethnic groups of Europe, North America, Africa and Asia (Japan), based on the results of investigations carried out by dozens of authors. Recent discoveries have been supplemented with corresponding data concerning the skeletal remains of the jaws of individuals living from the ice age to the middle ages. The results show unbelievably large diversities as regards the frequency of agenesis of third molars in different populations from practically zero (Tasmania) to nearly 100% (Mexican Indians). This remarkable fact is not, however, the only reason why the problem of third molars remains a major concern for anthropologists, anatomists and stomatologists. Indeed, agenesis of third molars present only one of the most important anomalies which characterizes this tooth. It is necessary to look for the roots of the said variability in the remarkably complicated phylogenetic development undergone by the third molar from the time of our predecessors to the present day. Most of today's authors are of the opinion that although significant involution changes have occurred in third molars, that with the advent of hominization the number of teeth in individuals has stabilized at eight for every quadrant of dentition. For this reason it is not possible to regard agenesis of third molars as the manifestation of the phylogenetic reduction in the number of teeth, but as the developmental anomaly which is the result of a mutation and selection process based on heredity. The results are completed with an analysis of the value of agenesis of one to four third molars according to the individual quadrants and gender. A knowledge of these indicators is necessary in order to study the relationship between agenesis of third molars and hypodontia of the other teeth.

Biological Evolution↗
PubMed2001

Indications for the extraction of impacted third molars in a semi-urban Nigerian Teaching Hospital.

Medical records and radiographs of 450 consecutive patients that had extractions of impacted third molars at a semi urban Nigerian Teaching Hospital were studied to highlight common indications for such extraction. Infections accounted for majority (69.6%) of third molars extracted at the lower jaw, followed by periodontal pocket formation distal to second molars (12.5%). Caries, cysts, jaw fractures and neoplasm were respectively responsible for 5.7%, 0.6%,0.5% and 0.3% of impacted lower third molars extracted. Obscure jaw pain (48.4%) was the most common reason for removing impacted upper third molars. Only 2 (3.2%) upper third molars were extracted because of infections. Since pericoronitis was the most common indication for the extraction of impacted lower third molars, it was suggested that where resources for third molar surgery are limited, it may seem reasonable to prioritise removal of asymptomatic third molar covered by soft tissue alone.

Adult↗