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Journal of Stomatology, Oral and... Sep 2022This study aims to explore the prevalence of Iatrogenic retroposition of the lips sequel (IRLS) after bicuspid extraction, associated dentofacial characteristics and the...
AIM
This study aims to explore the prevalence of Iatrogenic retroposition of the lips sequel (IRLS) after bicuspid extraction, associated dentofacial characteristics and the effectiveness of surgical treatment.
MATERIAL
and methods: Patients with bicuspid extraction as part of an orthodontic treatment plan were retrospectively included. IRLS was identified by clinical evaluation and cephalometric Legan and Burstone analysis. Association of demographic and cephalometric variables were assessed. The effectiveness of combined orthodontic-orthognathic correction of the retroposition of the lips was evaluated.
RESULTS
Out of 144 patients with extracted bicuspids, eight Class I patients, nine Class II patients and five Class III patients were seeking treatment because their lips had retruded as a consequence of compensating orthodontic treatment. Lower jaw bicuspid extraction and a decreased vertical facial height in Class II patients correlated significantly more with IRLS development. Postoperative cephalometric analysis of orthodontic-orthognathic treated patients reported improvement in lip projection and naso-labial angle. Only two Class I patients reported postoperative normalization of the lip position according to Legan and Burstone.
CONCLUSION
The consequence of bicuspid extractions on soft tissue profile differs according to skeletal jaw relation. The impact of orthognathic surgery on IRLS is beneficial, although insufficient to completely correct the facial profile when judged on cephalometric standards.
Topics: Bicuspid; Cephalometry; Humans; Iatrogenic Disease; Lip; Retrospective Studies
PubMed: 35659532
DOI: 10.1016/j.jormas.2022.05.025 -
Journal of Prosthodontics : Official... Oct 2018To evaluate bicuspid axial wall height effect on the fracture mode of adhesively luted, all-ceramic CAD/CAM crowns with a 20° total occlusal convergence (TOC).
PURPOSE
To evaluate bicuspid axial wall height effect on the fracture mode of adhesively luted, all-ceramic CAD/CAM crowns with a 20° total occlusal convergence (TOC).
MATERIALS AND METHODS
Recently extracted premolars were randomly divided into 4 groups (n = 12) with all-ceramic crown preparations accomplished using a high-speed handpiece inserted into a milling device. Specimens were prepared containing occlusogingival axial wall heights of 3, 2, and 1 mm as well as a group containing a flat preparation surface with no axial wall height. All preparations contained a 20° TOC. Completed preparation surface area was determined, and preparation features confirmed using a digital measuring microscope. Scanned preparations (CEREC) were fitted with milled and crystallized lithium disilicate full coverage restorations and luted with a self-etching adhesive resin cement after hydrofluoric acid etching and silanation. All manufacturer recommendations were followed. Specimens were stored at 37°C/98% humidity for 24 hours. Specimens were tested to failure at a 45° angle to the long axis of the tooth root on a universal testing machine. Failure load was converted to MPa using the available bonding surface area with mean data analyzed using Kruskal-Wallis/Dunn's (p = 0.05) RESULTS: The 3 mm preparation height specimens were similar to the 2 mm specimens, and both demonstrated significantly stronger failure load than the 1 mm axial wall height and flat preparation specimens. The flat preparation and 1 mm axial wall height specimens all failed adhesively, while the 2 mm and 3 mm specimens failed largely due to tooth fracture.
CONCLUSIONS
Further evidence is provided that CAD/CAM adhesive techniques may compensate for less than ideal preparation features. Under the conditions of this study, bicuspid preparations with a 20° TOC restored with adhesively luted, CAD/CAM e.max CAD crowns require at least 2 mm of axial wall height, but further planned fatigue studies are necessary before definitive recommendations can be made.
Topics: Bicuspid; Computer-Aided Design; Dental Occlusion; Dental Prosthesis Design; Dental Restoration Failure; Dental Restoration, Permanent; Dental Stress Analysis; Humans
PubMed: 29457311
DOI: 10.1111/jopr.12760 -
The Angle Orthodontist Jul 1987Various combinations of orthodontic force, luxation, and observation are applied to 12 teeth traumatically intruded in 3 large dogs. All showed root resorption to some...
Various combinations of orthodontic force, luxation, and observation are applied to 12 teeth traumatically intruded in 3 large dogs. All showed root resorption to some degree. Early orthodontic repositioning, with luxation if immobile, produced the best recovery.
Topics: Animals; Ankylosis; Bicuspid; Dogs; Prognosis; Root Resorption; Tooth Avulsion; Tooth Diseases; Tooth Mobility; Tooth Movement Techniques
PubMed: 3477970
DOI: 10.1043/0003-3219(1987)057<0234:TIT>2.0.CO;2 -
The Angle Orthodontist Apr 1984The effects of a passive lingual arch on lower incisor and molar positions after extraction of first bicuspids are analyzed. Results indicate that a lingual arch can be...
The effects of a passive lingual arch on lower incisor and molar positions after extraction of first bicuspids are analyzed. Results indicate that a lingual arch can be effective in maintaining arch length, while still allowing normal changes in incisor, cuspid and second bicuspid positions.
Topics: Bicuspid; Cephalometry; Child; Dental Arch; Equipment Design; Female; Humans; Incisor; Male; Malocclusion; Molar; Orthodontic Appliances; Serial Extraction
PubMed: 6588772
DOI: 10.1043/0003-3219(1984)054<0163:TPLAIF>2.0.CO;2 -
American Journal of Orthodontics May 1978
Topics: Bicuspid; Malocclusion; Patient Care Planning; Serial Extraction
PubMed: 277071
DOI: 10.1016/0002-9416(78)90247-6 -
The Angle Orthodontist May 2006The aim of this systematic review was to examine, in an evidence-based way, what kind of orthodontic anchorage systems/applications are evaluated and their... (Meta-Analysis)
Meta-Analysis Review
The aim of this systematic review was to examine, in an evidence-based way, what kind of orthodontic anchorage systems/applications are evaluated and their effectiveness. A literature survey from the Pub Med and Cochrane databases covering the period from January 1966 to December 2004 was performed. Randomized controlled trials (RCT), prospective and retrospective controlled studies, and clinical trials comparing at least two anchorage situations were included. Two reviewers selected and extracted the data independently and also assessed the quality of the retrieved studies. The search strategy resulted in 494 articles, of which 14 met the inclusion criteria. Two main anchorage situations were identified: anchorage of molars during space closure after premolar extractions and anchorage loss in the incisor or premolar region (or both) during molar distalization. Because of contradictory results and the vast heterogeneity in study methods, the scientific evidence was too weak to evaluate anchorage efficiency during space closure. Intraoral molar distalization leads to anchorage loss in various amounts depending on the choice of distalization unit. Most of the studies had serious problems with small sample size, confounding factors, lack of method error analysis, and no blinding in measurements. To obtain reliable scientific evidence, controlled RCT's with sufficient sample sizes are needed to determine which anchorage system is the most effective in the respective anchorage situation. Further studies should also consider patient acceptance and cost analysis as well as implants as anchorage.
Topics: Bicuspid; Humans; Incisor; Molar; Orthodontic Anchorage Procedures; Orthodontic Space Closure; Research Design; Serial Extraction; Tooth Movement Techniques
PubMed: 16637733
DOI: 10.1043/0003-3219(2006)076[0493:OA]2.0.CO;2 -
Journal of Endodontics Jun 2017The comparative anatomy of contralateral premolars has not been previously studied. The purpose of this micro-computed tomography investigation was to qualitatively and... (Comparative Study)
Comparative Study
INTRODUCTION
The comparative anatomy of contralateral premolars has not been previously studied. The purpose of this micro-computed tomography investigation was to qualitatively and quantitatively assess and compare the morphology of contralateral premolars in terms of length, canal width, dentinal thicknesses, accessory canals, root canal configurations, isthmi, C-shapes, root canal orifices, and apical foramina. The null hypothesis (H) is that contralateral premolars are more morphologically similar than randomly assigned pairs for simple morphometric measurements (lengths, canal widths, and dentinal thickness).
METHODS
Forty-one intact premolar pairs (n = 82) extracted from 28 patients were scanned with micro-computed tomography and reconstructed. Quantitative comparative assessment of measurements was performed by pairwise statistical analysis of contralateral and random pairs with Student t test and one-sample t test. All measured parameters (lengths, widths, and thicknesses) were normalized by Z score so that they could all be compared on a common scale. A correlation study was also performed. Canal configurations and isthmi were classified according to preexisting classification schemes. The number and location of accessory canals and apical foramina were registered and compared.
RESULTS/CONCLUSIONS
Contralateral premolar pairs demonstrated a high degree of similarity in terms of the linear measurements (lengths, widths, and thicknesses). The apical portion (foramina, C-shapes, and accessory canals) did not demonstrate bilateral symmetry. The comprehensive statistical analysis of the normalized parameters by Z score showed no statistically significant differences between the contralateral premolar pairs. The null hypothesis (H) was accepted.
Topics: Adolescent; Adult; Bicuspid; Child; Dental Pulp Cavity; Dentin; Female; Humans; Male; Tooth Apex; X-Ray Microtomography; Young Adult
PubMed: 28377148
DOI: 10.1016/j.joen.2017.01.012 -
Oral Surgery, Oral Medicine, and Oral... Dec 1975
Topics: Adult; Bicuspid; Female; Humans; Radiography
PubMed: 1060039
DOI: 10.1016/0030-4220(75)90454-5 -
Journal of Clinical Orthodontics : JCO Mar 2022
Topics: Bicuspid; Humans; Orthodontic Anchorage Procedures; Tooth Movement Techniques
PubMed: 35706148
DOI: No ID Found -
Oral Surgery, Oral Medicine, and Oral... Jan 1992
Topics: Adolescent; Bicuspid; Female; Fused Teeth; Humans; Radiography; Tooth, Supernumerary
PubMed: 1603558
DOI: 10.1016/0030-4220(92)90175-p