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PubMed1986

Second molar extractions: a review.

In this exhaustive review, a number of parameters related to maxillary and mandibular second molar extractions are discussed. The parameters reviewed include the timing of extractions and the effect of extractions on third molar eruption, posterior interdigitation, and incisor imbrication. The advantages and limitations of this procedure are outlined. The available information strongly suggests that the extraction of second molars relieves crowding in the posterior part of the arch, causes faster eruption of third molars, and diminishes the number of unerupted and/or impacted third molars. Consideration of the decrease in the number of impacted third molars after second molar extraction should be balanced with the fact that the extracted teeth are usually sound and are unimpacted. In addition, the third molars that do erupt frequently are poorly angulated and/or in poor contact with the first molars. This will necessitate an additional "late" period of fixed-appliance therapy to bring these teeth into good occlusion.

Adolescent↗

PubMed1991

Prolonged effects of hypofunction on the mechanical strength of the periodontal ligament in rat mandibular molars.

The ultimate loads required to extract three mandibular molars in the dissected jaw were examined after elimination of the antagonistic teeth for up to 64 days. The ultimate loads in the experimental first and second molars decreased rapidly in the first few days, while those in the third molar remained low during the same period in both experimental and control groups. The ultimate loads in all three molars of the experimental animals then increased gradually towards the end of the experiment at rates similar to those in controls. Maximum relative reductions of the ultimate load were observed within the first 8 days in all three molars. An increase in the length of roots was also found in all hypofunctional molars. Daily rates of root elongation ranged from 13 to 19 microns/day in the control and from 18 to 26 microns/day in the experimental molars during the whole experiment. The greatest value (80 microns/day) was obtained during the first 8 days in the third molars of both control and experimental animals. Thus the mechanical strength of the periodontal ligament estimated in vitro may be increased by the development of teeth and by non-functional occlusal contacts with the opposing gingiva-covered alveolar ridge deprived of its tooth crowns. The ligament of the third molar was apparently immature at the beginning of the experiment.

Animals↗

PubMed1991

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.

Adult↗

PubMed1994

A long-term, follow-up, radiographic evaluation of asymptomatic impacted third molars in orthodontically treated patients.

Long-term follow-up orthopantomographs of 251 adult orthodontically treated former patients showed 113 clinically asymptomatic impacted third molars in 58 patients. Radiographic assessment revealed contact of impacted third molars with the second molars, resorption of maxillary and mandibular second molars, as well as pathologically widened pericoronal spaces of the maxillary and mandibular third molars. The comparison of the sagittal third molar position in 52 impacted teeth revealed a sagittal change in all third molars from post-treatment to follow-up: maxillary and mandibular third molars had rotated to a more upright position and showed an increase in mesio- or distoangulation or a change of axial inclination. The lack of predicting factors such as age, period of impaction, extent of space deficiency, developmental stage, level of eruption, and bone conditions leads the authors to recommend that former orthodontic patients be recalled at regular intervals for assessment of changes in the condition and position of erupting or impacted third molars.

Adult↗

PubMed2001

Reduction of the hypocone of the maxillary first molar and Class III malocclusion.

This study was conducted to examine the incidence of evolutionary changes of the maxillary molars in orthodontic patients and to investigate the association of this event with craniofacial growth. Among 4,892 Japanese patients treated at the orthodontic clinic of Hiroshima University Dental Hospital, 59 patients presented with a defect of the distolingual cusp of the maxillary first molar. They consisted of 52 female patients and seven male patients with a mean age of 14.7 years. Eruption of the maxillary first and second molars was delayed and the third molar was congenitally missing in all of these patients. Thirty-seven patients exhibited Class III malocclusion (Class III evolution group). The Z scores of cephalometric measurements were compared between the Class III evolution group and the Class III control group. The latter group consisted of 37 Class III subjects with no evolutionary dental anomalies and no orthodontic history. The tooth developmental score (TDS) for each age at the initial record was compared with Nolla's standard tooth developmental score (STDS) for equivalent ages using paired t-tests. The Z scores for Ptm'-A and Ar-A were significantly smaller in the Class III evolutionary group than in the Class III control group (P < .05). The TDS for the maxillary first and second molars were significantly smaller than the STDS for these molars (P < .01). The TDS for the maxillary second molar was significantly larger than the STDS for the maxillary third molar (P < .01). This study revealed that an evolution change of the maxillary molar is more common (P < .05) in female patients than in male patients, is more frequent (P < .05) in subjects with Class III malocclusion, and is related to the anteroposterior undergrowth of the maxilla.

Adaptation, Biological↗

PubMed2002

Inflammatory mediators and periodontitis in patients with asymptomatic third molars.

PURPOSE: Our goal was to report the detection and levels of gingival crevicular fluid (GCF) inflammatory mediators, sampled at the mesial of 4 first molars and distal of 4 second molars, in 316 patients with asymptomatic third molars. PATIENTS AND METHODS: Levels of GCF inflammatory mediators, interleukin (IL)-1 beta and prostaglandin (PG)E(2), were determined and log transformed for each patient. Z scores were calculated using the mean and standard deviation of the log values for the entire sample of 316 patients. The log mediator levels and Z scores of patients who had probing depths (PDs) less than 5 mm (n = 238) were compared with patients with at least 1 PD equal to or greater than 5 mm (n = 78) on the distal of second molars or around third molars. A periodontal Composite GCF Inflammation Score was calculated for each patient by summing the Z scores obtained for IL-1 beta and PGE(2) for that patient. RESULTS: The levels of GCF IL-1 beta and PGE(2) were higher if a patient had a PD equal to or greater than 5 mm in the third molar region. The Composite GCF Inflammation Score indicated "elevated inflammation" if a PD equal to or greater than 5 mm was found in the third molar region as well. CONCLUSIONS: These data suggest that asymptomatic patients with PD equal to or greater than 5 mm in the third molar region with associated periodontal attachment loss have increased levels of biochemical mediators of inflammation compared with patients with PD less than 5 mm. These findings are consistent with the concept that early periodontitis in young adults that initiates in the third molar region is associated with increases in key inflammatory mediators.

Adolescent↗

PubMed2003

[Fourth molars in the maxilla and mandible--a rare phenomenon].

The occurrence of supernumerary teeth is not uncommon. The preferred location of the supernumerary teeth is in the maxilla, mostly incisors, followed by the molars. Supernumerary molars are divided into two types, depending on their location: distomolars and paramolars. Distomolars are supernumerary teeth that are distal to the third molars, while paramolars are supernumerary teeth on the side of the molars. The paper describes an unusual case of four distomolars. The two maxillary distomolars were unerupted, in a vertical position distal to the third molars. Their morphology was normal but they were smaller than the regular molars. The two mandibular distomolars were unerupted, in a horizontal position distal to the third molars. Their morphology was normal but they were smaller than the regular molars. Cases of four distomolars with normal morphology are extremely rare and have seldom been reported in the dental literature. The phenomenon is interesting especially considering the fact that in modern man, missing third molars are becoming a common finding.

Adult↗

PubMed2004

Utilization of third molars in the orthodontic treatment of skeletal class III subjects with severe lateral deviation: case report.

AIM: This clinical report discusses the importance and use of third molars in the adult patient by presenting a case in which their use during orthodontic treatment allowed occlusal improvement. SUBJECT AND TREATMENT PLAN: The patient was a Japanese adolescent boy who had a skeletal Class III malocclusion with severe lateral deviation of the mandible, significant loss of posterior occlusal vertical dimension, due to premature loss of the maxillary and mandibular left first molars, and furthermore, both first molars had advanced carious lesions that had resulted in reduced crown heights and bilateral chewing surfaces. The mandible had shifted to the left, with a bilateral chewing pattern and a lack of posterior vertical alveolar height, which in turn had produced an abnormal occlusal plane and curve of Spee. The maxillary arch was expanded, the maxilla was moved downward and forward, and the mandible was moved slightly backward and rotated open to increase posterior vertical alveolar and crown height. The reconstruction of a functional occlusal plane was achieved by uprighting the posterior teeth to correct asymmetric posterior vertical alveolar and crown height, using a full multibracket system incorporating four third molars and closing the space from the missing first molars and extraction of the questionable first molars. RESULTS: A normal overbite and overjet and adequate posterior support and anterior guidance were established, achieving a better intercuspation of the posterior teeth. A favorable perioral environment was created, with widened tongue space to produce an adequate airway. A well-balanced lip profile and almost symmetric face were achieved using the four wisdom teeth without extraction of the four premolars. Subsequent mandibular growth, with development of posterior vertical alveolar height and temporomandibular joint adaptation, has resulted in an almost symmetric posterior vertical height and joint structure between right and left sides. These factors have contributed to the occlusal stability maintained for more than 5 years. CONCLUSION: In the growing patient, with missing and/or early advanced caries of the first molars, it may be more beneficial to plan occlusal improvement through extraction of the questionable first molar rather than premolar extraction. This method of treatment can equalize posterior vertical dimension and does not restrict tongue space. In addition, this treatment method addresses the clinician's concern about postorthopedic relapse due to tongue habits and eruption of the third molars.

Adaptation, Physiological↗

PubMed1977

The evolution of molar occlusion in the Cercopithecidae and early Catarrhines.

Those Eocene prosimians which are possible catarrhine ancestors have four blade-like crests on each lower molar. Each crest shears in sequence across two upper molar crests. Occluding crests are concavely curved to hold the foods being sheared. Each of two medial lower molar crests bordering the principal crushing surface shear past single upper molar crests at about the same time the lateral lower molar crests contact the second rank of upper molar crests. Grinding and crushing areas are restricted to hypoconid, trigonid, and protocone surfaces. Oligocene catarrhine molars have increased crushing-grinding capacities and maintained but modify their shearing. As the crushing surface of the protocone expands and a crushing hypocone is added, the "second rank" upper molar shearing crests are functionally reduced. At the same time medial crests are increasingly emphasized so that the total shearing capacity remains virtually unchanged. Marginal shearing blades are straight edged; leading edges of occluding blades are set at different angles to the occlusal plane so that blades contact at only one point at any given time. Early Primates have separate crushing basins surrounded by shearing blades. Catarrhines tend to link explanding crushing surfaces anteroposteriorly into a continuous surface between all molars. A cladistic analysis based on both new and previously recognized characters indicates that: 1. Apidium may be more closely related to Aegyptopithecus than to Parapithecus; 2. cercopithecids are derived from a Parapithecus-related stock; 3. Oreopithecus could equally well have come from an Apidium or Aegyptopithecus stock.

Animals↗

PubMed2004

Statistical genetics of molar cusp patterning in pedigreed baboons: implications for primate dental development and evolution.

Gene expression and knock-out studies provide considerable information about the genetic mechanisms required for tooth organogenesis. Quantitative genetic studies of normal phenotypic variation are complementary to these developmental studies and may help elucidate the genes and mechanisms that contribute to the normal population-level phenotypic variation upon which selection acts. Here we present the first quantitative genetic analysis of molar cusp positioning in mammals. We analyzed quantitative measures of molar cusp position in a captive pedigreed baboon breeding colony housed at the Southwest National Primate Research Center in San Antonio, Texas. Our results reveal complete pleiotropy between antimeric pairs of traits--i.e., they are influenced by the same gene or suite of genes. Mandibular morphological homologues in the molar series also exhibit complete pleiotropy. In contrast, morphological homologues in maxillary molar series appear to be influenced by partial, incomplete pleiotropic effects. Variation in the mandibular mesial and distal molar loph orientation on the same molar crown is estimated to be genetically independent, whereas the maxillary molar mesial and distal loph orientation is estimated to have partially overlapping genetic affects. The differences between the maxillary and mandibular molar patterning, and the degree of genetic independence found between lophs on the same molar crown, may be indicative of previously unrecognized levels of modularity in the primate dentition.

Animals↗

PubMed1986

Mandibular molar displacement secondary to the use of forces to retract the maxilla.

Using previously described computer-aided techniques, we have been able to characterize quantitatively the displacements of the lower first molar associated with the use of several different therapeutic modalities that are conventionally employed to retract the maxilla in the treatment of Class II malocclusion. The total displacement of the molar has been partitioned into two components associated respectively with displacement of the entire mandible and with local interosseous migration (dental compensation) of the molar within the mandible. A further attempt has been made to partition treatment-associated effects from nontreatment-associated effects. While considerable variability in effect was observed within each sample on a case-by-case basis, some important normative trends did emerge. Contrary to our expectations, it was found that in each of the treatment groups, the mean local intraosseous rotational effect (Table IIB.2) was of greater magnitude than the mean effect of mandibular rotation (Table IIB.1). The character of the intraosseous rotation differed significantly (P less than 0.05) between the control group and each of the treatment groups. In the control group, a mean mesial crown tipping (that is, "proclination") was noted. In each of the treatment groups, a mean distal crown tipping ("uprighting") was noted. In both the cervical and intraoral groups, the lower molar tended to displace mesially more than in the control or high-pull groups. This mesial displacement derived from the mesial displacement of the mandible (Table IIC.3), rather than from displacement of the tooth within the bone (Table IIC.4). In both the high-pull and the intraoral groups, the lower molar erupted within the mandible significantly more than in the control and cervical groups (Table IIC.6). The statistically significant supereruption/extrusion of the upper molar in the cervical group (Table IIC.2) was not accompanied by an associated inhibition of the eruption of the lower first molar (Table IIC.6). In general, it seems reasonable to infer that the growth-related displacement of the mandible influenced the final position of the lower first molar more profoundly than did the treatment-associated displacement of the upper molar.

Activator Appliances↗

PubMed1989

The eruption of third molars in adults: a 10-year longitudinal study.

Among 829 participants of the Veterans Administration Dental Longitudinal Study examined over four triennial cycles, 97 persons (11.7%) had one or more unerupted third molars, for a total of 151 teeth, when the study was initiated. During the first 10 years of the study, 10 subjects had 14 unerupted third molars extracted, while in 10 persons 11 third molars erupted. Four of the latter persons each had one third molar removed subsequent to eruption. Three of the 11 erupted third molars were in functional occlusion. The position of 4 of the 11 "erupting" third molars appeared to remain unchanged relative to radiographic landmarks. Thus, their apparent clinical eruption may have been due to a reduction in the level of the gingival tissue in the area distal to the second molar tooth in association with periodontitis. The eruption of third molars in older adults appears to be a more frequent phenomenon than was previously recognized. Most erupting third molars had some associated pathologic condition, including caries and periodontitis.

Adult↗

PubMed1992

Effect of extraction of partly erupted third molars on subgingival microorganisms.

This study was made to investigate the effect of extraction of third molars on subgingival microbes in 39 generally and gingivally healthy men with an average age of 20.2 years (SD 0.9). Microbial samples were taken from the pericoronal space of symptom-free partly erupted lower third molars and from the adjacent gingival pockets of the second molars. The samples were cultivated anaerobically. All partly erupted third molars were extracted from 20 subjects. A control group of 19 subjects was left untreated. Microbe sampling was repeated 2 and 5 months postoperatively with highly significant results. It was shown that at baseline the number of black-pigmented gram-negative bacteria and Fusobacterium species was more frequent in third molar than in second molar sites. The total bacterial count decreased significantly at the second molar sites after extraction of the third molars when compared with the control group. Before the extractions, black-pigmented gram-negative bacteria were detected in 45% of the test subjects and Actinobacillus actinomycetemcomitans in 20%. The respective postoperative figures were 30% for black-pigmented gram-negative bacteria and 10% for Actinobacillus actinomycetemcomitans. Capnocytophaga species were not affected by the extractions. The findings suggest that erupting third molars may harbor harmful bacteria that can be reduced by eradicating the foci.

Adult↗

PubMed1983

Dental nerve regeneration in rats. II. Autoradiographic studies of nerve regeneration to molar pulp and dentin.

The autoradiographic technique was used to analyze the degeneration and regeneration of sensory nerves to rat molars and gingiva following cut or crush injury to the right inferior alveolar nerve. At 2 days after nerve injury there was almost complete denervation of the first molar, partial denervation of the second molar, and minimal effect on the innervation to the third molar and gingiva. The degree of sensory deficit and recovery for these same rats had been previously determined. Reinnervation of the first molar was analyzed in terms of axon number and location, intensity of axon labeling, and type of nerve injury. At 6 days, neither the cut injury nor crush injury rats had any reinnervation of their first molars. By 7 days, 3 of 4 rats had axons reinnervating first molars; in those teeth there was approximately one-fourth of the normal number of axons in the pulp, and very few axons in the dentin. These rats still had as large a molar sensory deficit as the 7 day rat and 6 day rats that had no reinnervation. By 3 weeks there were one-half to three-fourths of the normal axon numbers in the pulp, one-fourth to one-half of the normal axon numbers in dentin; and sensitivity was at least half-recovered. By 6 weeks, numbers of axons in the pulp and dentin were either normal or slightly less than normal; axons had grown back into dentin to the same depth as in normal teeth; and complete recovery of sensitivity had occurred. The regenerating axons had greater than normal labeling intensity at 1 week and 3 weeks in all rats. Those with the crush nerve injury had somewhat greater numbers of reinnervating axons at 1 week and 3 weeks than the cut injury rats. A structure-function comparison for the molars showed that return of sensitivity correlated with reinnervation of both pulp and dentin.

Alveolar Process↗

PubMed1991

Mesial force from unerupted third molars.

Erupting mandibular third molars are implicated as a cause of anterior crowding of mandibular teeth. The goal of this two-part investigation was to measure the mesial force exerted by unerupted mandibular third molars. We hypothesized that such a force increases the tightness of all proximal posterior tooth contacts mesial to the mandibular second molar, and that surgical removal of third molars relieves the tightness by eliminating this force. The contact tightness between mandibular posterior teeth was measured bilaterally in 20 patients with bilateral unerupted mandibular third molars, immediately before and after unilateral removal of a third molar. We found unexpectedly that mean proximal tightness decreased bilaterally in all contacts that were measured after unilateral removal of a third molar, and we did not detect a mesial force exerted by unerupted third molars. We suspected that this bilateral relief of contact tightness resulted from placing the patients in a supine position for surgery. The second part of the experiment was conducted to determine the effects of postural change on proximal contact tightness where no surgery had been performed. For ten subjects we discovered a mean decrease in the tightness of all mandibular posterior contacts 2 hours after the patient had been moved from an upright to a supine position. The greatest mean decrease (-32%, p less than 0.0001) was found at the most posterior tooth contact. We conclude that surgical removal of unerupted mandibular third molars does not significantly reduce proximal contact tightness, but that simple movement from an upright to a supine position relieves such tightness dramatically.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed2006

Molar distalization with pendulum appliances in the mixed dentition: effects on the position of unerupted canines and premolars.

INTRODUCTION: The pendulum appliance allows for rapid molar distalization without the need for patient compliance. Its efficiency has been confirmed in a number of clinical studies. However, the potential interactions and positional changes between the deciduous molars used for dental anchorage and the erupted and unerupted permanent teeth have yet to be clarified when this appliance is used for molar distalization in the mixed dentition. METHODS: Twenty-nine patients in the mixed dentition each received a modified pendulum appliance with a distal screw and a preactivated pendulum spring for bilateral distalization of the maxillary molars. The patients were divided into 4 groups based on dentition stages: patient group 1 (PG 1, n = 10) was in the early mixed dentition; patients had resorption of the distal root areas of the deciduous molars being used for dental anchorage, and the unerupted premolars were located at the distal margin of the deciduous molar root region. Based on radiographs taken before placement of the pendulum appliance, patient group 2 (PG 2, n = 10) was diagnosed as having a central location of the unerupted premolars. In the third group (PG 3, n = 4), the first premolars were already erupted and could be integrated into the dental anchorage, but the canines were not yet erupted. In the fourth group (PG 4, n = 5), the first premolars and both canines were fully erupted. RESULTS: Statistical analysis of the measured results showed significant differences in the side effects between PG 1 and PG 2. In patients being treated with pendulum appliances, the anchorage quality of the deciduous molars that were already partially resorbed in the distal root area was comparatively reduced. Consequently, the mesial drift of the deciduous molars and incisors was increased, without impairing the extent and quality of the molar distalization. Anchorage loss in the supporting area had no direct impact on the sagittal position of the unerupted premolars in the early mixed dentition. CONCLUSIONS: If permanent teeth have already started to erupt in the supporting area, additional space restrictions should be avoided in patients with critical topography, especially if there is little space for the unerupted canines. At this stage of the mixed dentition, premolar extraction or augmentation of the supporting area with extraoral headgear offers a therapeutic alternative to intraoral distalization appliances with exclusively dental anchorage.

Analysis of Variance↗

PubMed2006

Prediction of mandibular third-molar impaction in adolescent orthodontic patients.

INTRODUCTION: The purpose of this study was to identify risk factors for mandibular third-molar impaction in adolescent orthodontic patients. METHODS: Radiographs made before (T1) and after (T2) treatment and at least 10 years postretention (T3) of 134 patients that allowed accurate diagnosis of impaction vs eruption of at least 1 mandibular third molar were evaluated. RESULTS: Univariate logistic regression analyses at T1 showed that the decision to extract premolars (P <.05), an increase of 1 mm in mesial molar movement (P <.05), and an increase of 1 mm in eruption space measured from second molar to Xi point (centroid of the ramus) (P <.01) reduced the risk of impaction by 63%, 22%, and 30%, respectively. An increase of 1 degrees in mandibular third-molar angulation relative to the occlusal plane increased the risk of impaction by 11% (P <.01). Multivariate logistic regression analyses at T1 showed that reduced eruption space (P <.01), signs of forward mandibular growth rotation (P <.01), and female sex (P <.05) increased the risk of impaction. However, association tests documented increased frequencies of extractions and more mesial molar movement in female patients with erupted third molars. Univariate logistic regression analyses at T2 showed that every millimeter of increase in eruption space measured from the second molar to the anterior border of the ramus and to Xi point reduced the risk of impaction by 29% and 22%, respectively (P <.01), whereas every degree of increase in the angle between the occlusal surface and the occlusal plane increased the risk of impaction by 11% (P <.01). Multivariate logistic regression analyses at T2 showed that increased eruption space reduced the risk of impaction (P <.05), whereas increased mesial angulation of the third-molar bud (P <.01) and signs of forward growth rotation (P <.05) increased the risk of impaction.

Adolescent↗

PubMed2006

Reproducibility of radiographic stage assessment of third molars.

UNLABELLED: The aim of this study was to determine intra- and inter-observer variability of the developing third molar from panoramic radiographs. Formation of third molars was assessed according to stages described by modified Demirjian et al.'s methods: Moorrees et al. [C.F.A. Moorrees, E.A. Fanning, E.E. Hunt, Age variation of formation stages for ten permanent teeth, J. Dent. Res. 42 (1963) 1490-1502] and Solari and Abramovitch [A.C. Solari, K. Abramovitch, The accuracy and precision of third molar development as an indicator of chronological age in Hispanics, J. Forensic Sci. 47 (2002) 531-535]; in addition, data were also analysed unmodified, i.e. Haavikko [K. Haavikko, The formation and alveolar and clinical eruption of the permanent teeth, an orthopantomograph study, Proc. Finn. Dent. Soc. 66 (1970) 104-170] and Demirjian et al. [A. Demirjian, H. Goldstein, J.M. Tanner, A new system of dental age assessment, Hum. Biol. 45 (1973) 211-227]. The sample was a random selection of 73 panoramic radiographs from patients aged 8-24 years. After training, the left maxillary and mandibular third molars were scored on two separate occasions without knowledge of previous scores. Cohen's Kappa and percentage agreement were calculated for each method, for maxillary, for mandibular third molars and combined. Percentage agreement for stages was also calculated. Intra-observer agreement was greater for mandibular third molars compared to maxillary third molars, and better for methods with fewer stages. Kappa values indicated good agreement for most methods; the best was Demirjian et al.'s method for mandibular third molar with very good agreement (K = 0.80) for the first author, good agreement for the second author (K = 0.75) and good agreement between observers (K = 0.75). The stages with best agreement were Demirjian's stage E [A. Demirjian, H. Goldstein, J.M. Tanner, A new system of dental age assessment, Hum. Biol. 45 (1973) 211-227] and Moorrees et al.'s stage Cc and R1/4 [C.F.A. Moorrees, E.A. Fanning, E.E. Hunt, Age variation of formation stages for ten permanent teeth, J. Dent. Res. 42 (1963) 1490-1502]. CONCLUSIONS: Having clearly defined stages and fewer stages allowed better reproducibility of third molar formation.

Adolescent↗