Permanent Second Molars Research Articles

Evaluation of Timetable of the Second Permanent Molar Calcification among Children between 5 and 17 Years of Age

Objective: This study evaluates timetable of calcification stages of the second permanent molars (SPMs) based on panoramic radiographic findings from a selected group of Iranian patients. Methods: This descriptive, analytical and cross sectional study uses 715 panoramic radiographs of subjects with optimal quality between 5 to 17 years of age (n=60 for each age group) whom were selected from the referrals to the departments of Orthodontics and Pediatric Dentistry of at Tehran University of Medical Sciences, Iran. Patients with systemic diseases or any kind of syndromes were excluded. Calcification stages were determined based on Demirjian's classification. Data were analyzed using generalized estimating equation (GEE). Results: Only 20% of SPMs of 5 year-olds were in their 2nd stage of calcification and the remaining showed higher stages. The mean age of crown completion was around 8.5 years while the mean ages of root completion for the open and closed apices were 13 years and 3 months and 15.5 years, respectively. Also calcification occurred at earlier ages among girls. Conclusion: Timetable of calcification of SPMs is useful to predict the onset of puberty. Demirjian’s classification well matches Iranian population for determining calcification stage of SMPs. Keywords: Permanent Molar, Tooth Calcification, Forensic Dentistry, Iranian Population Key Messages: Mean age at different stages of calcification of the second permanent molars could be effective in forensic dentistry as well as for diagnostic and treatment purposes.

Daimi Birinci Molar Dişin Geç Dönemde Çekiminden Sonra İdeal Spontan Yer Kapanması: Bir Olgu Serisi

OBJECTIVE: Before they haven't completed its development, permanent first molar(PFM) teeth which have been decayed and treated with root canal therapy is mostly extracted before the child even reaches adult hood. With correct evaluation of patient, these extracted teeth’s space can be ideally closed by permanent second molars(PSM). The aim of the study is to learn under which conditions we can provide ideal closure and occlusion in patients who refer to us in a late stage. MATERIALS AND METHODS: 695 patients aged 6-16 years who had PFM tooth extracted at a Faculty of Dentistry were retrospectively evaluated from the system. 117 patients had their PFM tooth extracted after the ideal age range and 15 of them were found to meet the inclusion criteria. Panoramic films of 21 teeth of 15 patients with spontaneous ideal closure were evaluated before extraction and after eruption of PSM teeth. The contact between the PSM and the second premolar was recorded and intraoral photographs were taken. Rotations in the PSM and second premolars, axis disturbances towards the linguale/buccal, midline deviations in both jaws, TMJ dysfunctions and chewing habits were evaluated. RESULTS: When PFM extraction was performed, PSM development stage was determined as Demirjian G in 19 teeth and H stage in 2 teeth. Tipping was observed in 80%, and rotation in 9.5% of the PSM teeth. Clinically, it has been determined that 85% of the patients don’t notice the PFM deficiency, don’t complain about their teeth and don’t consider orthodontic treatment. CONCLUSIONS: Within the limits of this study, it has been observed that ideal spontaneous space closure and ideal occlusion can be achieved, although it was extracted in late period. In ideal occlusion, rotation or tipping after extraction in late period; permanent third molar presence and eruption pressure were more effective than the eruption direction and angle of the PSM tooth.

EVALUATION OF ROOT CANAL MORPHOLOGY OF MAXILLARY PERMANENT SECOND MOLARS USING CONE BEAM COMPUTED TOMOGRAPHY IN CHENNAI ? A CROSS SECTIONAL STUDY.

30Sep 2019 EVALUATION OF ROOT CANAL MORPHOLOGY OF MAXILLARY PERMANENT SECOND MOLARS USING CONE BEAM COMPUTED TOMOGRAPHY IN CHENNAI - A CROSS SECTIONAL STUDY. Nur Liyana Hannah Binti Izham Akmal and Mahesh Ramakrishnan. Reader,Saveetha Dental College and Hospital, Saveetha Institute Of Medical And Technical Science, Saveetha University. Graduate Student,Department of Pedodontics,Saveetha Dental College and Hospital, Saveetha Institute Of Medical And Technical Science, Saveetha University.

Association of obesity with the eruption of first and second permanent molars in children: a systematic review.

Eruption timing of permanent teeth, particularly first and second molars, is of great importance due to its influence on occlusion, caries risk and timing of preventive and orthodontic intervention. To evaluate the evidence assessing the correlation between obesity and eruption time of first and secondpermanent molarsin children under 16years of age as compared to normal-weight children.Asecondary aim was to assess the total number of erupted teeth in both groups. A systematic search of databases including PubMed, MEDLINE, EMBASE, Scopus and Web of Science was conducted. Studies that assessed the effect of body mass index (BMI), adjusted BMI or z scores on dental eruption were included. National Institute of Health 'Quality Assessment Tool for Observational Cohort and Cross-sectional Studies' was used to assess the quality of included papers. A random-effects model with its 95% confidence intervals (CIs) was considered for meta-analysis. A total of 381 papers were screened following duplicate removal. Twenty-six papers were read in full text, of which 19 were excluded. Seven studies were included in this review; one was longitudinal, and six were cross-sectional in design. A positive association of dental eruptionwith obesity was noted in six studies. Two studies were included in the explorative meta-analysis, the results of which indicated that obese, 12-year-olds are likely to have one more erupted tooth than their counterparts with a mean difference (MD) of (0.99, 95% CI 0.628-1.352). There appears to be a positive correlation between obesity and dental eruption including theeruption timing of first and secondpermanent molars. Main risk of bias arises from the cross-sectional nature of included studies and lack of control of potential confounders. Further high-quality evidence is required to elucidate this association. Registration PROSPERO (CRD42017084368). PROSPERO (CRD42017084368).

Effects of first permanent molar extractıon on space changes observed in the dental arch using data mining method.

The high incidence of caries in first permanent molars (FPMs) makes premature extraction of these teeth common. The extraction of the permanent teeth results in various changes in the dental arch. The aim of this study was to evaluate space closure, the eruption of second permanent molars (SPMs), and changes in dental arch after extraction of the FPMs. Eruption of 83 SPMs was recorded and radiographically developmental stage of these SPMs in the pre-extraction panoramic radiograph was assessed. Space was measured between the distal surface of the second premolar and the mesial surface of SPM. Out of 55 patients, 28 (50.9%) were males and 27 (49.1%) were females. Thirty-seven (44.6%) of 83 teeth belonged to category 1, 17 (20.5%) teeth belonged to category 2, and 5 (6.02%) teeth belonged to category 3. Although category 4 was not found, 24 (28.9%) teeth were observed to be in category 5. Out of all SPMs, 10.8% represented the ''ideal'' stage of Demirjian's dental development, stage E. In patients who had the FPMs extracted before the eruption of the SPM, it is important with regards to the patients' comfort and health to review the patient regularly and to determine any need for orthodontic treatment.

A Study of Cusp Base Areas in the Maxillary Permanent Molars of American Whites

The focus of this descriptive study was toexplore the patterns of variation of base crown areas forthe four major cusps on the maxillary first and secondpermanent molars in a cohort of contemporary NorthAmerican whites of western European descent. Acomputer-assisted photogrammetric method was usedto measure two-dimensional areas of the cusps. Rankingof mean cusp size was the same for M1 and M2, namelyprotocone > paracone > metacone > hypocone. In concertwith field theory, size decreased while variability (CV)increased across this same sequence. Overall area of M1(97 mm2) is 13% larger than M2 (86 mm2) in this sample.Most cusps exhibited significant sexual dimorphism,with greater differences for the distal cusps within atooth and from M1 to M2. Intercorrelations of cusp areaswere notably low (r2 < 15%) both within and betweenM1 and M2, suggesting considerable independence informative rates of each cusp and low morphologicalintegration of these constituents of the occlusal table.Limited comparative material in the literature suggeststhat cusp areas may valuably extend the quantitativecomparisons for genetic and biological studies beyondconventional tooth crown width and length.

Agenesis of first and second permanent molar: Literature review and cases reports

SUMMARYTooth agenesis is the absence of one ormore teeth in temporary or permanent dentition.This anomaly in craniofacial malformationsis more frequent, that may occur asan isolated anomaly or as part of a geneticsyndrome. The incidence of agenesis ofpermanent teeth varies1.6-9.6%, excludingthird molars, while in primary dentition therange is 0.5 to 0.9%. The factors that arerelated to dental agenesis, are the genes andsignaling pathways. Specifically Pax9 hasbeen associated with the lack of permanentmolars. Agenesis of the first and secondpermanent molars is not very commonbut has been reported in the literature andcan be isolated or causing malocclusion.Therefore, early diagnosis is essential toestablish a treatment plan to help guide theeruption of other teeth and prevent sequeldue to agenesis. Four clinical cases are presentedof patients with agenesis of first andsecond permanent molars to complementthe literature review.Key words: Dental agenesis, first permanentmolars, second permanent molars,malocclusion, organogenesis defect.

A Contemporary Examination of First and Second Permanent Molar Emergence

The emergence of first permanent molars (FPMs) and second permanent molars (SPMs) is an important developmental milestone influencing caries risk and the timing of sealant placement. Emergence times have been shown to vary by sex and race/ethnicity, while recent reports suggest a positive association with adiposity. Amid the changing demographics of the US population and the rising rates of pediatric overweight/obesity, we sought to examine the association of body mass index (BMI) with FPM/SPM emergence in a representative sample of US children and adolescents. We used cross-sectional data from 3 consecutive cycles of the National Health and Nutrition Examination Survey (2009 to 2014). The FPM analysis included ages 4 to 8 y (n = 3,102 representing ~20 million children), and the SPM analysis included ages 9 to 13 y (n = 2,774 representing ~19 million children/adolescents). The Centers for Disease Control and Prevention’s growth chart data were used to calculate age- and sex-specific BMI percentiles, as measures of adiposity. Initial data analyses relied on descriptive statistics and stratified analyses. We used multivariate methods, including survey linear and ordinal logistic regression and marginal effects estimation to quantify the association between pediatric overweight/obesity and FPM/SPM emergence, adjusting for age, sex, and race/ethnicity. Forty-eight percent of 6-y-olds and 98% of 8-y-olds had all FPMs emerged, whereas SPM emergence varied more. Blacks (vs. whites) and females (vs. males) experienced earlier emergence of FPMs and SPMs. Overweight/obesity was associated with earlier FPM emergence, particularly among black females. Obesity but not overweight was associated with earlier SPM emergence. Overall, overweight/obesity accounted for 6 to 12 mo of dental acceleration. This study’s results emanate from the most recent US-representative data and affirm that FPM/SPM emergence varies by race/ethnicity and sex and is positively influenced by BMI. Future research should further elucidate these associations with detailed eruption data and examine the implications of this variation for clinical care.

Lower first permanent molars: developing better predictors of spontaneous space closure.

First, first permanent molars (FPMs) of poor prognosis are often planned for extraction at an 'ideal time' so that second permanent molars (SPMs) erupt favourably to replace them. However for lower FPM extractions, timing is not an accurate predictor of success. The aim of this study was to identify additional radiographic factors that could better predict the degree of spontaneous space closure of the lower SPM following FPM extraction. Data from a previous study of 127 lower SPMs from 66 patients was re-analysed by incorporating additional radiographic factors. These included calcification stage of the bifurcation of the SPM, position of the second premolar, mesial angulation of SPM in relation to the FPM, and presence of the third permanent molar. Results were analysed using ordered logistic regression. Only 58 per cent of FPMs extracted at the 'ideal time' (SPM development at Demirjian stage E) had complete space closure. The best outcomes resulted from a combination of SPMs not at Demirjian development stage G, together with the presence of mesial angulation of the SPM and presence of the third permanent molar, where 85 per cent of those cases had complete space closure. Apart from extraction timing of the FPM, consideration must also be given to the presence of the third permanent molar and angulation of the SPM in order to ensure a reliable degree of spontaneous space closure of the lower SPM.

The evaluation of spontaneous space closure after the extraction of first permanent molars

In the UK, first permanent molars (FPMs) of poor prognosis are often planned for extraction so that second permanent molars (SPMs) erupt favourably to replace the FPMs. However, there is little published data to support this treatment strategy. The aim of this study was to assess the success of planned FPM extractions conducted 5years ago at a dental hospital in London. Two hundred and thirty-six SPMs from 63 patients were clinically assessed. The position of each SPM was recorded in relation to the second premolar, against patient Angle's classification and SPM radiographic development stage at the time of FPM extraction. Results were analysed using ordered logistic regression. At the time of FPM extraction, only 54% of SPMs were at the "ideal" stage of development (Demirjian's dental development stage E). Upper and lower arches yielded significantly different results with 92% of all upper extractions resulting in complete space closure regardless of SPM development stage. Only 66% of lower FPMs extracted at SPM stage E had complete space closure and no significant relationship was found between lower SPM development stage and its subsequent space closure. Space closure in both arches also appeared independent of patient Angle's classification. Although only over half the patients had FPMs extracted at the "ideal time", this did not appear to influence successful positioning of the upper or lower SPM. More research is required to investigate and confirm which predictive parameters have a significant effect on post-extraction orthodontic development, especially in the lower arch.

A 13-year follow-up of a comprehensive program of fissure sealing and resealing in Varkaus, Finland

The objective of the study was to examine the coverage of the sealing program on first permanent molars (FPMs) and second permanent molars (SPMs) and first and second premolars (FSPMs), as well as to monitor the fate of the sealed teeth over time. All patients born in 1977 who had had regular check-ups in the Varkaus Health Center, Finland (n = 166) were included in the 1996 study. Data on the annual state of each tooth had been collected retrospectively since 1983. The coverage for the sealant program was 95%, 92%, and 6% of the FPMs, SPMs, and FSPMs, respectively. Out of the FPMs sealed at age 6 years, 28% were subjected to resealing, 13% developed occlusal, and 15% proximal caries during a 13-year follow-up period. From the SPMs sealed at age 11 years, 24% were subjected to resealing, 4% developed occlusal caries, and less than 2% proximal caries during the 9-year follow-up. None of the sealed FSPMs and only 1% of the non-sealed ones developed occlusal caries during the 9-year period. The mean DMF in the study population (n = 160) at age 12 years was 0.8 (n = 124), compared to a nation-wide mean value of 1.2. A large percentage of the FPMs and SPMs were sealed and then resealed during the study period. Although the study design lacked a control group for comparison, the lower caries rates of this study compared to the results of other studies with only a single application of sealants suggest a major role for resealing.