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At least 703 records · Page 39Linked to original sources
PubMed1998

Sexual dimorphism in the tooth crown dimensions of the second deciduous and first permanent molars of Taiwan Chinese.

Sexual dimorphism in the crown components in the second deciduous molar (dm2) and the first permanent molar (M1) of the dental casts taken from Chinese living in Kaohsiung (Taiwan) was investigated. Mesiodistal and buccolingual crown diameters, and 4 main-cusp sizes in the maxillary molars and mesiodistal diameters of the trigonid and talonid in the mandibular molars were measured using a digital caliper (0.01 mm). Percentage sexual differences were calculated. With the exception of trigonid mesiodistal diameters, the mean values of males were larger than females. In both of dm2 and M1 the mean values of the trigonid mesiodistal diameters were slightly larger in females than in males, but the differences were not significant. Percentage sexual dimorphism was smaller in the mesiodistal diameters than in the buccolingual in both dm2 and M1. The crown components showed larger sexual difference in dm2 than in M1, while in the maxilla the external crown size showed larger sexual difference in M1 than in dm2. The buccal cusps showed larger sexual difference than the lingual in the maxillary molars and the talonid showed larger sexual difference than the trigonid in the mandibular. Sexual dimorphism of dm2 and M1 in their crown components displayed similar pattern, although the different degree was noted. This result is thought to relate to the fact these molars belong to the first dentition embryologically.

China↗
PubMed2000

[Taurodontism and the pyramidal tooth at the level of the molar. Prevalence in the Senegalese population 15 to 19 years of age].

This study was done to establish the prevalence of taurodontism and pyramidal molars in Senegalese people using the criteria of SCHIFFFMAN and CHANANNEL for taurodontism and the criteria of BRABANT for pyramidal molar, the first and second molars on the panoramic radiograph of 150 consecutive 15-19 year-old Senegalese people were assessed. Results have shown that taurodontism and pyramidal molars were present in 48.6% of patients (20% of teeth). Taurodontism was present in 48% (18.8% of teeth) of patients whereas prevalence of pyramidal molar was 4.6% (1.6% of teeth). Taurodontism was alone in 91.6% of case while pyramidal molar was alone in 8.6% of case.

Adolescent↗
PubMed2001

Analysis of 1202 orthopantograms to evaluate the potential of forensic age determination based on third molar developmental stages.

A total of 1202 orthopantograms of young dental patients were analyzed to assess the correlation of third molar root development with chronological age. The investigated patients were treated at a university dental clinic on an outpatient basis, included a variety of demographic characteristics (600 males and 602 females, 28% of other than central European background), and were 15-24 years old when the radiographs were obtained. Radiographs in which more than one third molar were either missing due to agenesia or extraction, or not evaluable because of deep destruction or marked tilting, were not included in the analysis. Our findings show that the growth patterns of third molars, based on seven defined stages of root development, did correlate with chronological age; age estimation when applied to a specific individual would involve a margin of error of +/- 2-4 years. There were no significant differences between the left and right jaw segments, but the stage of root development was generally more advanced in the upper than in the lower third molars. Root development was also more advanced among boys than among girls of the same age. There were no apparent differences in growth patterns based on national/ethnic background. While only 2.5% of 18-year-olds revealed fully developed third molars in all four quadrants, this percentage leaped to 38.4% among the 21-year-olds. To summarize, while the developmental stage of third molars is not per se a highly useful indicator of chronological age in juveniles and young adults, it is nevertheless a valuable supplementary parameter given the scarcity of other available age indicators.

Adolescent↗
PubMed2000

[The effects of distalization of upper molars in Class II malocclusion by pendulum appliance].

OBJECTIVE: To study the mechanics of Pendulum appliance, and its effects on craniofacial and dentoalvaolar structure. METHODS: 16 class II malocclusion patients (13 females and 3 males) were selected as the subjects, aged from 9.3 to 22.8 years(13.6 on average). All the patients were treated with Pendulum appliance. The duration for distolization of upper molars was from 1 to 6 months(3.7 months on average). Cephalomatric analysis was used. RESULTS: 1. The upper molar was distalized by 3.59 mm per side with mainly tilting movement. 2. Incisors moved mesially by 3.28 mm per side (tilting movement). 3. Anterior overjet was increased by 1.56 mm after treatment and more than 6 mm space was created per side. 4. The upper molars extruded slightly by 0.69 mm. 5. The width of upper arch was increased by 2.03, 1.66, 1.10 mm at molar, premolar and canine region respectively. 6. The Pendulum appliance had less effects on craniofacial structure because of short treatment time. CONCLUSIONS: The Pendulum appliance can distalize the upper molars effectively without patients' active cooperation. However, it should be cautions in using the appliance because of its side effects on tilting of molars and mesial movement of incisors.

Acrylic Resins↗
PubMed1992

[Germectomy. The germ of the third mandibular molar in children: remove or preserve?].

Third molars are often removed in order to prevent complications and various other problems associated with impacted third molars and their removal. Abortion of mandibular third molars is a procedure carried out at an early age in those subjects where there is insufficient room for the eruption of the third molars. On the other hand one can also decide to remove the second molars and to annexate orthodontically the third molars in the arch.

Child↗
PubMed2002

The accuracy and precision of third molar development as an indicator of chronological age in Hispanics.

The accuracy and precision of chronological age estimation based on the stages of third molar tooth development was studied in a sample of 679 radiographs from individuals of Hispanic origin. The age range was 14.0 to 25.0 years. Eight raters from the University of Texas Health Science Center at Houston Dental Branch evaluated the radiographs according to Demirjian's schematic definitions of crown and root formation. The objective of this study was to evaluate the chronology of third molar development in Hispanics following the protocol of a previous study. Within the Hispanic population, the rate of male third molar development is greater than that of female third molar development for ten stages of crown-root formation. Also within this Hispanic population sample, the rate of maxillary third molar development is ahead of mandibular third molar development. The mean absolute difference between chronological age and estimated age was +/-3.0 years in females and +/- 2.6 years in males.

Adolescent↗
PubMed2002

The surgical removal of mandibular third molars: a study in decision making.

OBJECTIVE: The aim of this study was to investigate and analyze the angulation of and the various indications for removal of mandibular third molars in Jordanians as a representative Arab sample. METHOD AND MATERIALS: The data included in this retrospective study were obtained from the clinical and radiographic records of 1,282 patients undergoing mandibular third molar surgery during a 5-year period from 1994 to 1999. The indications for removal of the mandibular third molars were classified in accordance with age and gender. The angular position of mandibular third molars was registered. RESULTS: A total of 2,252 mandibular third molars were removed from 740 male patients (57.7%) and 542 female patients (42.3%) aged 14 to 67 years. Pericoronitis was the most common indication for surgery, affecting 1,055 teeth (46.8%). Caries was observed in 519 third molars (23.0%). The vertical angular position was most commonly found (1,383 teeth; 61.4%) followed by the mesioangular position (407 teeth; 18.1%). CONCLUSION: The results obtained in this study are similar to those reported in earlier studies carried out elsewhere, although the incidence of periodontitis among Jordanians was significantly higher and occurred in older patients, and prophylactic removal was performed less frequently than has been reported in other countries.

Adolescent↗
PubMed2002

The NiTi Distalizer. A non-compliance maxillary molar distalizer.

Maxillary molar distalization is oftentimes necessary in orthodontic treatment. Headgear, the original appliance designed for this movement, requires considerable patient compliance to be effective. Other molar distalizing appliances may cause the molars to tip. This article describes the NiTi Distalizer, a fixed molar distalizing appliance that requires no patient compliance. It also produces minimal molar tipping as its forces are directed near the center of resistance of the molars being distalized. The appliance can be used in both growing and nongrowing patients. In addition, the NiTi Distalizer is capable of opening the bite to allow easy mandibular bracket placement. Once placed, the NiTi Distalizer requires no adjustment and is easily put into passive mode when sufficient distalization has been accomplished.

Adolescent↗
PubMed2002

[Factors involved in the etiology of hypomineralized first permanent molars].

Severe hypomineralized first permanent molars (cheese molars) can be found in children. The aetiology of this phenomenon is unknown. The aim of this study is to collect more information about the causes of such molars. Parents of 24 children with severe cheese molars and of 21 controls without cheese molars, matched for age, living area and sex were interviewed. The mean age of the 45 children was 9.9 year (; ssd: 2.02). A questionnaire about the medical data from birth to four years of age and the medical situation of the mother during pregnancy was sent to the parents. No significant differences were found concerning weight and length at the time of birth between the two groups. Also no significant differences were found for the period of breast-/and bottle-feeding and for problems of the mother during pregnancy and child delivery. The mothers were healthy during pregnancy. Compared to the control group the children with cheese molars were ill more often Significant differences were found for pneumonia, high fever and inflammation of the middle ear.

Adult↗
PubMed2002

Treatment and posttreatment dentoalveolar changes following intrusion of mandibular molars with application of a skeletal anchorage system (SAS) for open bite correction.

The skeletal anchorage system (SAS) consists of titanium anchor plates and monocortical screws that are temporarily implanted in either the maxilla or the mandible as absolute orthodontic anchorage. With SAS, anterior open bite can be improved by the counterclockwise rotation of the mandible, accompanied by the intrusion of molars. The present study was designed to evaluate treatment and posttreatment dentoalveolar changes following the intrusion of mandibular molars. Nine adult open bite patients (7 women and 2 men) successfully treated with SAS were included in the following study. The amount of intrusion, relapse, and dentoalveolar changes were measured on cephalometric radiographs, panoramic radiographs, and dental casts. The results of this study were as follows: (1) the average amount of intrusion of the mandibular first and second molars was 1.7 mm and 2.8 mm, respectively; (2) the average relapse rates were 27.2% at the first molars and 30.3% at the second molars; (3) there were no significant changes in crestal bone heights, clinical crown length, or root length; and (4) counterclockwise rotation of the mandible and decrease of anterior facial height were observed during treatment. Thus, it was concluded that SAS would be a valid modality to intrude mandibular molars for correction of open bite.

Adolescent↗
PubMed2003

Morphology of third molar teeth with incompletely formed apices on the basis of panoramic radiograms.

Third molar teeth are causative factors of many oral pathologies. Lower third molars are the most often retained teeth and the origin of considerable pain. The aim of the study is a presentation of the morphology of third molars with incompletely formed apices on the basis of panoramic radiograms. The material comprised routine panoramic radiograms taken in the years 1996-2000. In the cases where third molars with incompletely formed apices were found, there was determined the location of the teeth in the alveolar process. The angle between occlusal plane and tooth axis was measured, which allowed determination of angularity of the teeth. Retromolar space width ratio was also calculated as a prognostic radiographic feature on which an estimation of future eruption of mandibular third molars could be based. In retained teeth the reasons for impaction, such as incorrect angularity, insufficient retromolar space, presence of pathological lesions impeding eruption, were analysed. Panoramic radiograms proved useful in diagnostics of morphology of third molars with incompletely formed apices.

Adolescent↗
PubMed1992

Loss of the first permanent molar and caries experience of adjacent teeth.

The caries experience of the occlusal and distal surfaces of the second premolars and the occlusal and mesial surfaces of the second permanent molars was examined in four groups of subjects aged 19-20 years. Group 1 comprised subjects with first permanent molars present, Group 2 subjects with early loss of the first permanent molar (before the age of 11-12 years), Group 3 subjects with late loss of the first permanent molar (after 11-12 years but before 15-16 years) and Group 4 included a combination of Group 2 and Group 3. Loss of the first permanent molar was associated with increased caries or restorations in the occlusal surfaces of adjacent teeth, but reduced caries or restorations in the proximal surfaces of adjacent teeth. Early loss of the first molar was associated with significantly greater caries or restoration experience in proximal surfaces than late loss, but no difference was detected for occlusal surfaces.

Adolescent↗
PubMedDate not supplied

Management of occlusal and developmental disturbances resulting from an ankylosed maxillary second primary molar: case report.

This case report presented the orthodontic management of an ankylosed primary molar. Trauma to the maxillary right second primary molar resulted in the infraocclusion of the affected tooth as well as the mesial tipping of the adjacent first permanent molar and displacement of the permanent successor. After extraction of the ankylosed primary molar, orthodontic therapy was performed to upright the adjacent permanent molar and to gain the lost space of its permanent successor. By the application of orthodontic mechanics, the maxillary right permanent first molar was uprighted and the maxillary right permanent second premolar was brought to its proper position.

Bicuspid↗
PubMed2004

The association of third molars with mandibular angle fractures: a meta-analysis.

OBJECTIVE: To estimate the relative risk of mandibular angle fractures among people with a lower third molar compared with those without a lower third molar. METHODS: Data for a case-control meta-analysis were obtained by performing a literature search in MEDLINE and EMBASE to identify suitable observational studies. To be included, studies had to present data on patients with mandibular fractures, incorporate cross-classified information about the presence of a lower third molar and indicate whether the fracture was a mandibular angle fracture on the ipsilateral side. RESULTS: Six studies, involving 3,002 patients with mandibular fractures, met the inclusion criteria. Crude relative risk estimates for an angle fracture, comparing patients with a third molar with those without, ranged from 1.2 to 12.7. There was evidence of heterogeneity across the 6 studies (p = 0.001), but when 2 studies with less methodologic rigour were excluded, a test of homogeneity was no longer statistically significant (p = 0.22). The estimated relative risk across the remaining 4 studies was 2.4 (95% CI 1.9 to 3.0). CONCLUSIONS: The presence of a lower third molar may double the risk of an angle fracture of the mandible. This could have a bearing on any clinical decision on whether to extract the molar.

Adult↗
PubMed2003

Pattern of third molar impaction in a Singapore Chinese population: a retrospective radiographic survey.

One thousand orthopantomograms (OPGs) of patients 20-40 years old were examined. Where impacted third molars were present, the angle and depth of impaction were recorded. Results were analysed using the Pearson chi2 test. 68.6% of OPGs showed at least one impacted third molar. The frequency was three-fold higher in the mandible (1024/1079=90%) than in the maxilla (306/1077=28%), with a significantly higher frequency (P<0.05) in females (56%) than males (44%). The mesioangular impaction was the most common, and 80% of all impacted third molars were partially buried in bone. Of the 429 bilateral occurrence of impacted third molars, 423 were in the mandible. It was concluded that the frequency of impacted third molars in the Singapore Chinese population studied was generally two to three times that reported in races of the Caucasian stock. There was also double the frequency of impacted third molars when compared to a previous study in a Chinese population published in 1932 with females being more frequently affected than males.

Adult↗
PubMed2004

Scanning electron microscopic investigation of incidence, location, and size of accessory foramina in primary and permanent molars.

OBJECTIVE: The purpose of this study was to determine and compare the incidence, location, and size of accessory foramina in the furcation region of permanent and primary molars. METHOD AND MATERIALS: A random sample of 100 extracted human permanent maxillary and mandibular first and second molars (25 teeth of each type) and a random sample of 100 extracted human primary maxillary and mandibular molars (50 teeth of each type) were used. The crowns and roots of each tooth were removed at a point 1.5 mm apical to the external furcation region, and a second cut was made at a point 1 mm apical to the cementoenamel junction. The specimens were examined using scanning electron microscopy at magnifications ranging from x 10 to x 1,250. The incidence, location, and size of accessory foramina were documented and statistically analyzed. RESULTS: Of the 100 permanent molars examined, 79% had accessory foramina with diameters ranging from 10 microm to 200 microm. Accessory foramina were present in 94% of the primary molars, with diameters varying from 10 microm to 360 microm. The incidence of accessory foramina was significantly higher in primary than in permanent molars. CONCLUSION: The presence of accessory foramina with large diameters may imply that an inflammatory process can spread from pulpal to periodontal tissues and vice versa.

Dental Pulp Cavity↗
PubMed2004

Morphology of root canal cross-sections of resected roots of first and second lower molars.

Precise preparation of the root canal ostium with a view to hermetical closing with retrograde root filling is an important prognostic factor determining the success of the procedure of tooth resection. Root canals interconnected with a narrow isthmus may cause problems both in endodontic treatment and in retrograde filling. The aim of this work is the research of the transverse cross-section of root canals of first and second lower molars on the resection model. The research encompasses 100 randomly selected molar teeth: 50 first and 50 second lower molars. The tooth root apexes were cut 3 mm below the apex and examined under an electron microscope, special attention being paid to the shape of root canal cross-sections. In the group of first molar teeth, in 20% the presence of an isthmus between canals in the proximal roots was observed; in the group of second molar teeth an isthmus between the canals of proximal roots occurred in 18% of the cases. It seems that the relatively high percentage (20%-18%) of the occurrence of an isthmus, 3 mm below the root apex, between two elongated transverse cross-section proximal root canals of first and second molars should encourage particular caution in the retrograde filling of the above-mentioned canals during the procedure of resection.

Dental Pulp Cavity↗
PubMed1991

[The relevance of the loss of first permanent molar for the periodontium of neighbouring teeth].

There is a controversial discussion according to treatment of the early loss of first permanent molar. The aim of this investigation was to study the change of periodontal conditions of the teeth neighbouring the gap. We investigated 33 patients with 55 gaps. The average time of first molar loss was 10.5 years. The position of neighbouring teeth was influenced by the early loss of the first molar. Oral hygiene and self cleaning of the periodontal tissues was of good quality in this region. The bleeding on probing was smaller in this region compared with control teeth. The pocket depth of the second molar was higher than that of the second premolar. The loss of alveolar bone detected by radiography was greater in the second molar compared with the second premolar and also in the distal periodontal site of the second molar and the mesial site of the second premolar controlled with sites neighbouring the gap.

Adult↗