The Role of Inter-Canine Width in Late Lower Arch Crowding

1994 ◽  
Vol 21 (1) ◽  
pp. 53-56 ◽  
Author(s):  
Margaret E. Richardson
Keyword(s):  
Second Molar ◽  
Lower Arch

Changes in lower inter-canine width in relation to changes in crowding in the years following second molar eruption were examined in a group of 30 subjects who had an increase in lower arch crowding and a group of 30 subjects who had no such increase in crowding.

scholarly journals Post-natal Effect of Overexpressed DKK1 on Mandibular Molar Formation

2011 ◽  
Vol 90 (11) ◽  
pp. 1312-1317 ◽  
Author(s):  
X.L. Han ◽  
M. Liu ◽  
A. Voisey ◽  
Y.S. Ren ◽  
P. Kurimoto ◽  
...  
Keyword(s):  
Developmental Stages ◽  
Formation Rate ◽  
Third Molar ◽  
Nestin Expression ◽  
Second Molar ◽  
Mandibular Molar ◽  
Targeted Expression ◽  
Enamel Knots ◽  
Dentin Formation

Dickkopf-related protein 1 (DKK1) is a potent inhibitor of Wnt/β-catenin signaling. Dkk1-null mutant embryos display severe defects in head induction. Conversely, targeted expression of Dkk1 in dental epithelial cells leads to the formation of dysfunctional enamel knots and subsequent tooth defects during embryonic development. However, its role in post-natal dentinogenesis is largely unknown. To address this issue, we studied the role of DKK1 in post-natal dentin development using 2.3-kb Col1a1- Dkk1 transgenic mice, with the following key findings: (1) The Dkk1 transgene was highly expressed in pulp and odontoblast cells during post-natal developmental stages; (2) the 1st molar displayed short roots, an enlarged pulp/root canal region, and a decrease in the dentin formation rate; (3) a small malformed second molar and an absent third molar; (4) an increase of immature odontoblasts, few mature odontoblasts, and sharply reduced dentinal tubules; and (5) a dramatic change in Osx and nestin expression. We propose that DKK1 controls post-natal mandibular molar dentin formation either directly or indirectly via the inhibition of Wnt signaling at the following aspects: (i) post-natal dentin formation, (ii) formation and/or maintenance of the dentin tubular system, (iii) mineralization of the dentin, and (iv) regulation of molecules such as Osx and nestin.

Second Molar Extraction in the Treatment of Lower Premolar Crowding

1992 ◽  
Vol 19 (4) ◽  
pp. 299-304 ◽  
Author(s):  
Margaret E. Richardson ◽  
Donald J. Burden
Keyword(s):  
Second Molar ◽  
Lower Arch ◽  
Lower Premolar ◽  
Molar Extraction

Thirty-four children with lower premolar crowding were treated by extraction of second molars. Thirteen cases had mechanical lower arch treatment started not less than 6 months after extractions. The remainder had no treatment in the lower arch. The change in premolar crowding was measured, and the reasons why spontaneous alignment occurred in some cases and not in others were examined.

The role of accelerated dental development on the occurrence of aberrant dental traits that indicate malocclusion

2018 ◽  
Vol 41 (4) ◽  
pp. 397-403
Author(s):  
Brunilda Dhamo ◽  
Amanda M Nguee ◽  
Edwin M Ongkosuwito ◽  
Vincent W V Jaddoe ◽  
Eppo B Wolvius ◽  
...  
Keyword(s):  
Developmental Stages ◽  
Dental Development ◽  
Dental Age ◽  
Second Molar ◽  
Logistic Regression Models ◽  
Tooth Impaction ◽  
Mandibular Teeth ◽  
Dental Traits ◽  
2D And 3D

Summary Background Timing of dental development might help orthodontists to optimize initiation of treatment and to prevent and intercept dental misalignment. This study examines the association between timing of dental development and aberrant dental traits such as crowding, impaction, and hypodontia. Methods This study was performed using 4446 ten-year-old children from a multiethnic birth cohort, the Generation R Study. Dental development was defined using the Demirjian method. Crowding, impaction, and hypodontia were ascertained from 2D and 3D pictures and radiographs. We built three series of logistic regression models to test the associations of dental age with crowding, impaction, and hypodontia. Similar models were built to investigate the associations of the developmental stages of each left mandibular tooth with crowding, impaction, and hypodontia. Results Inverse associations were found between every 1-year increase in dental age and the presence of crowding [odds ratio (OR) = 0.84, 95% confidence interval (CI): 0.79, 0.89], impaction of teeth (OR = 0.66, 95% CI: 0.52, 0.84), and hypodontia (OR = 0.52, 95% CI: 0.47, 0.56). Lower developmental stages of the second premolar were associated with the presence of crowding (OR = 0.90, 95% CI: 0.83, 0.98). Lower developmental stages of the second premolar (OR = 0.88, 95% CI: 0.79, 0.98), first molar (OR = 0.76, 95% CI: 0.65, 0.90), and the second molar (OR = 0.83, 95% CI: 0.73, 0.94) were associated with the presence of tooth impaction. Lower developmental stages of all mandibular teeth except the central incisor were associated with hypodontia (P < 0.05). Conclusion Accelerated dental development is associated with lower occurrence of crowding, impaction, and hypodontia.

scholarly journals The role of microendodontics in the treatment of difficult cases such as C-shaped orifice of mandibular second molar with 5 canals

2008 ◽  
Vol 20 (3) ◽  
Author(s):  
Harry Huiz Peeters
Keyword(s):  
Root Canal ◽  
Anatomical Variation ◽  
Diagnostic Tools ◽  
Second Molar ◽  
Root Canals ◽  
Mandibular Second Molar ◽  
Distal Aspect ◽  
Difficult Cases

Finding the incidence of anatomical variation in root canals is commonly found as a result of more sophisticated diagnostic tools. Therefore, a thorough understanding of the normal anatomy of canals and its variations in root canal treatments would be helpful in achieving the desired result. Usual root configuration of a mandibular second molar is two separate roots, distal and mesial, with one canal each. The incidence of a distinct 4 root canal in the distal root of C- shaped orifices is a rare phenomenon that is reported in the literature. This case study shows how to locate and manage a rare anatomical variation of a mandibular second molar with a distinct 4 canal in the distal aspect in a C-shaped orifice successfully, the successful treatment of this case explains that we should have an awareness and understanding of the presence of additional canals and abnormal morphology of the canals. Beside that the operator’s perseverance and patience as well as sophisticated diagnostic tools such as the dental operating microscope, ultrasonic tips have an important role in treating unusual configurations of canals.

scholarly journals Open Bite Treated with Extractions and Temporary Anchorage Devices

2017 ◽  
Vol 7 ◽  
pp. 145-153
Author(s):  
Carol Weinstein ◽  
Ana Cruz ◽  
Bárbara Feldman
Keyword(s):  
Facial Asymmetry ◽  
Open Bite ◽  
Second Molar ◽  
Vertical Control ◽  
Temporary Anchorage Devices ◽  
Mandibular Position ◽  
Skeletal Pattern ◽  
Treatment Objective ◽  
The Right

A 13-year-old female with a chief complaint of continuing treatment presented with Class I skeletal pattern and slight facial asymmetry. Intraorally, she had Class II molar relationship on the right side, class l on the left side and 3mm. of midline discrepancy. Her upper and lower incisors were proclined and slightly crowded. She had 1 mm. overbite and 5mm. overjet in initial mounted casts. Splint therapy was suggested to stabilize mandibular position. After splint wear, a new mounting was made, which resulted in an open bite from left second molars to right second molars. A visual treatment objective was prepared with four first bicuspid extractions. After 9 months, upper second molars were extracted and temporary anchorage devices (TADs) were placed in the upper arch for intrusion. Detailing strategies such as bracket repositioning, occlusal adjustment, and elastics were used. The role of segmented models, second molar extraction treatment, and superimposition analysis in patients with discrepancies in mandibular position is discussed. It is concluded that a thorough case workup is needed to provide patients with a successful treatment for open bite cases. This case was treated orthodontically in 2 years with four bicuspid and upper second molar extractions as well as vertical control with TADs.

The Effects on the Lower Third Molar of the Extraction of the Lower Second Molar

1978 ◽  
Vol 5 (2) ◽  
pp. 99-103 ◽  
Author(s):  
John Lawlor
Keyword(s):  
Root Formation ◽  
Third Molar ◽  
Third Molars ◽  
Second Molar ◽  
Factors Associated ◽  
The Third ◽  
Lower Arch

A survey was carried out on 60 patients for whom lower second molar removal had been recommended at least 5 years previously, no other treatment being indicated in the lower arch. Of the 114 teeth recommended for removal, only 84 were extracted. Eighty four per cent of third molars erupted satisfactorily, where second molars had been extracted, while only 36 per cent of third molars erupted into good occlusion where the recommended extractions had not been carried out. In the extraction group, factors associated with a poor result were lack of third molar root formation at the time of removal of the second molar and space between the third molar crypt and the lamina dura of the second molar.

scholarly journals Efficacy of Operculectomy in the Treatment of 145 Cases with Unerupted Second Molars: A Retrospective Case–Control Study

2020 ◽  
Vol 8 (3) ◽  
pp. 65 ◽  
Author(s):  
Andrea Abate ◽  
Davide Cavagnetto ◽  
Andrea Fama ◽  
Marco Matarese ◽  
Francesca Bellincioni ◽  
...  
Keyword(s):  
Control Group ◽  
Case Group ◽  
Inclusion Criteria ◽  
Control Groups ◽  
Retrospective Case ◽  
Second Molar ◽  
One Year ◽  
And Control ◽  
Lower Arch ◽  
Control Study

The aim of this study is to assess whether operculectomy in patients with retained second molars eases spontaneous tooth eruption in respect to untreated controls. Two hundred and twenty-two patients with delayed eruption of at least one second molar were selected from the archives of the Department of Orthodontics, Milan, Italy. Eighty-eight patients, 40 males and 48 females (mean age 14.8 ± 1.3 years), met the inclusion criteria. Records were then divided into case and control groups. The case group consisted of patients that underwent removal of the overlaying mucosa over second molars (i.e., operculectomy) and the control group consisted of subjects who retained their operculum over an unerupted second molar and were followed for one year without performing any treatment. A total of 145 impacted second molars were considered (75 cases, 70 controls). A risk ratio with 95% confidence interval was used to compare the prevalence of eruption in the two groups. Spontaneous eruption occurred in 93.3% of cases in the operculectomy group (70/75), while in the control group, 10% teeth erupted spontaneously (7/70). Spontaneous eruption in the upper arch occurred in 95.2% of cases among treated patients (40 out of 42), while in the lower arch, spontaneous eruption occurred in 90.9% of cases (30 out of 33). Spontaneous eruption of the upper second molars in the control group occurred in 8.5% of cases (3 out of 35), while in the lower arch, it occurred in 8.5% (3 out of 35). Operculectomy can ease the spontaneous eruption of retained second molars and reduce the chances of inclusion.

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