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BioMed Research International 2014Mandibular premolars are known to have numerous anatomic variations of their roots and root canals, which are a challenge to treat endodontically. The paper reviews... (Review)
Review
Mandibular premolars are known to have numerous anatomic variations of their roots and root canals, which are a challenge to treat endodontically. The paper reviews literature to detail the various clinically relevant anatomic considerations with detailed techniques and methods to successfully manage these anomalies. An emphasis and detailed description of every step of treatment including preoperative diagnosis, intraoperative identification and management, and surgical endodontic considerations for the successful management of these complex cases have been included.
Topics: Bicuspid; Dental Pulp Cavity; Humans; Mandible
PubMed: 24895584
DOI: 10.1155/2014/512574 -
Journal of the World Federation of... Sep 2021Even though treatment of Class II malocclusion with premolar extractions and incisor retraction might affect incisor inclination and soft tissue profile, the effects of...
BACKGROUND
Even though treatment of Class II malocclusion with premolar extractions and incisor retraction might affect incisor inclination and soft tissue profile, the effects of bracket prescription on this have not been thoroughly assessed.
METHODS
Fifty patients (mean age: 13.6 years; 34% male) receiving extraction-based treatment with either standard Edgewise or pre-adjusted appliances were included. Between-group differences in the incisor inclination assessed with lateral cephalograms were analyzed statistically with linear/logistic regression at 5%.
RESULTS
Treatment-induced changes included retroclination of the upper/lower incisors (-3.0° and -2.0°, respectively), retraction of the upper/lower incisors (-3.4 mm and -1.5 mm, respectively), retraction of the upper/lower lip (-2.1 mm and -2.0 mm, respectively), and enlargement of the nasolabial angle (+1.6°). Analysis of the data adjusting for confounders indicated that the pre-adjusted group, after treatment, had larger inclination of the upper or lower incisors (+3.2° and +4.5°, respectively), more prominent upper incisors relative to the facial plane (+1.3 mm), and smaller interincisal angle (-7.3 or -7.7°). Post-treatment upper incisor inclination fell within the cephalometric norm significantly more in the pre-adjusted than in the standard Edgewise group (odds ratio 4.3; 95% confidence interval 1.1-16.6). No differences were found in lower incisor prominence, upper/lower lip prominence, or nasolabial angle.
CONCLUSIONS
Pre-adjusted appliances were associated with increased inclination of the upper and lower incisors, with more prominent upper incisors, and with more acute interincisal angle after retraction compared with standard Edgewise appliances. However, such differences did not translate in greater retraction of the upper/lower lips and greater nasolabial angle.
Topics: Adolescent; Bicuspid; Cephalometry; Female; Humans; Incisor; Lip; Male; Malocclusion, Angle Class II
PubMed: 34006493
DOI: 10.1016/j.ejwf.2021.04.001 -
Australian Dental Journal Sep 2007The literature regarding the dental and facial soft tissue effects of various forms of contemporary Class II orthodontic and orthopaedic treatment is reviewed. Treatment... (Review)
Review
The literature regarding the dental and facial soft tissue effects of various forms of contemporary Class II orthodontic and orthopaedic treatment is reviewed. Treatment outlined includes the use of headgear and functional appliances to attempt to modify the facial growth process and the extractions of premolar teeth as part of overall fixed appliance treatment. The conclusions of numerous articles highlight the fact that many approaches to treatment can be successful in correcting Class II malocclusions. Findings reported in recent literature also now show that the extractions of premolar teeth, for instance, as part of Class II treatment, do not necessarily lead to direct soft tissue effects. If lip profile changes do occur, it seems that they are far more likely to be positive aesthetically, than negative.
Topics: Bicuspid; Extraoral Traction Appliances; Humans; Lip; Malocclusion, Angle Class II; Orthodontic Appliances, Functional; Orthodontics, Interceptive; Tooth Extraction
PubMed: 17969283
DOI: 10.1111/j.1834-7819.2007.tb00484.x -
The Journal of Prosthetic Dentistry Jun 2022A custom emergence profile offers the ideal horizontal dimensions for an anatomic healing abutment. However, developing such an emergence profile can be a time-consuming...
STATEMENT OF PROBLEM
A custom emergence profile offers the ideal horizontal dimensions for an anatomic healing abutment. However, developing such an emergence profile can be a time-consuming and complex process.
PURPOSE
The purpose of this study was to develop a mathematical formula defining horizontal cervical tooth geometry to design prefabricated, tooth-specific, healing abutments.
MATERIAL AND METHODS
Cone beam computed tomography (CBCT) horizontal cross sections of 989 teeth on 54 participants were measured. For anterior and premolar teeth, 2 perpendicular ellipses were fitted onto the cervical tooth cross section that was defined by 3 parameters. The lingual ellipse followed the lingual outline of the tooth, and its diameter was the largest mesiodistal diameter of the tooth (parameter "a"); its buccolingual radius became parameter "b." The buccal ellipse was perpendicular to the lingual ellipse and followed the buccal outline of the tooth. The buccolingual radius of the smaller ellipse became parameter "c." For molars, the first ellipses followed the mesial outline of the tooth, and its larger diameter (parameter "a") matched the largest buccolingual diameter of the tooth. Its smaller radius became parameter "h1." The second ellipse was parallel to the first ellipse and followed the distal outline of the tooth. Its larger diameter became parameter "b", and its mesiodistal diameter became parameter "h2". Statistical differences between parameters were evaluated by the linear mixed model (α=.05 after Bonferroni adjustment). Pairwise comparisons were made separately for each parameter of the molars and separately for each parameter for the anterior teeth plus premolars. Teeth were put into the same parameter cluster if no significant differences were found between them for a specific parameter. If neither parameter (4 for molars and 3 for the other teeth) was different for 2 teeth, they were put into the same abutment cluster. The abutment clusters determined the type of anatomic healing abutment. The areas were calculated from the developed mathematical formula by using the parameters. In addition, cervical areas of 106 randomly chosen teeth were measured directly with a photo-editing software program. A computer algorithm was used to select 5 CBCT scans from the 54 by using the simple randomization method. The agreement between the 2 methods was evaluated by Bland-Altman analysis.
RESULTS
The lower and upper limits of agreement between the 2 methods were -8.57 and 7.36 mm, respectively, with no bias (-0.61 mm, P=.224). Significant differences were found between most parameters among the 14 tooth types (P<.001). Based on the parameters, 12 specifically distinct clusters were defined. Two tooth types were pooled into 1 abutment cluster: the maxillary first and second premolars and the mandibular first and second molars.
CONCLUSIONS
The cervical tooth cross section can be accurately defined by combining 2 elliptical elements. A comprehensive array of tooth specific emergence profiles can be provided by just 12 different prefabricated abutments, designed as per the recommended parameters.
Topics: Bicuspid; Cone-Beam Computed Tomography; Dental Implants; Humans; Mandible; Molar; Tooth; Tooth Root
PubMed: 33461775
DOI: 10.1016/j.prosdent.2020.11.023 -
Dental Traumatology : Official... Jul 2023Tooth auto-transplantation is a treatment option, which is often not considered to replace anterior maxillary incisors in children and adolescents. There are multiple...
BACKGROUND/AIMS
Tooth auto-transplantation is a treatment option, which is often not considered to replace anterior maxillary incisors in children and adolescents. There are multiple prognostic factors that may influence the outcomes of premolar auto-transplantation, but there is limited evidence from human studies. The aim of this study was to report the outcomes of auto-transplanted premolars in the anterior maxilla following traumatic dental injuries (TDIs) and to identify their prognostic factors.
MATERIALS AND METHODS
The clinical records of patients who had premolars transplanted in the anterior maxilla following TDI, with appropriate radiographs and a minimal of 1-year follow-up, were reviewed retrospectively. A specific data extraction form was developed, tested and used to collect information for the prognostic factors and outcomes.
RESULTS
The cohort included 120 patients with 144 auto-transplanted premolars. The mean age was 12.2 years (±2.0), and the mean observation period was 3.7 years (±1.8). The success rate was 80%, and the survival rate was 93%. Unfavourable outcomes included external replacement resorption in 12.5%, uncontrolled external inflammatory resorption in 2.7%, and both resorption types in 4.9% of teeth. Periodontal healing was significantly associated with donor tooth root maturity, graft handling at the time of surgery including ease of donor tooth extraction and placement at the recipient sites, recipient site alveolar bone status, and post-operative transplant mobility. Seventy-four teeth (53.4%) were immature at the time of transplantation where pulp revascularisation was anticipated, and 52 (70%) of those had radiographic and clinical signs of pulp healing. Pulp healing was significantly related to donor tooth eruption stage, ease of extraction of donor tooth, and ease of placement in the recipient site.
CONCLUSIONS
Good outcomes were observed for premolar teeth auto-transplanted in the anterior maxilla. The main prognostic factors were ease of extraction of donor tooth and ease of placement in the recipient sites and donor tooth root maturity.
Topics: Child; Adolescent; Humans; Bicuspid; Retrospective Studies; Maxilla; Tooth Root; Tooth Injuries
PubMed: 36740836
DOI: 10.1111/edt.12829 -
The Angle Orthodontist Jan 2021To investigate the correspondence between programmed interproximal reduction (p-IPR) and implemented interproximal reduction (i-IPR) in an everyday-practice scenario.... (Observational Study)
Observational Study
OBJECTIVES
To investigate the correspondence between programmed interproximal reduction (p-IPR) and implemented interproximal reduction (i-IPR) in an everyday-practice scenario. The secondary objective was to estimate factors that might influence i-IPR to make the process more efficient.
MATERIALS AND METHODS
Fifty patients treated with aligner therapy by six orthodontists were included in this prospective observational study. Impressions were taken at the beginning of treatment and after the first set of aligners. Data on p-IPR, i-IPR and technical aspects of IPR were gathered for 464 teeth. Statistical analyses included the Wilcoxon signed-rank test, Kruskal-Wallis, and multilevel mixed regression.
RESULTS
Mean difference between p-IPR and i-IPR was 0.15 mm (SD: 0.14 mm; P = .0001), with lower canines showing the highest discrepancy. Use of burs and measuring gauges resulted in a smaller difference (respectively: coeff.: 0.09, P = .029; coeff.: -0.06, P = .013). IPR was performed more accurately on the mesial surface of teeth than on the distal surface. Round tripping before IPR resulted in a slightly more precise i-IPR compared to the previous alignment (coeff.: -0.021, P = .041).
CONCLUSIONS
Implemented IPR tends to be less than p-IPR, especially for lower canines and distal surfaces of teeth. Burs tend to provide more precise i-IPR, especially compared to manual strips; however, there is variation between the techniques. Using a measuring gauge tends to increase the precision of i-iPR. As several factors influence the implementation of IPR, particular attention must be paid during the procedure to maximize its precision.
Topics: Bicuspid; Dental Enamel; Humans; Orthodontists
PubMed: 33339043
DOI: 10.2319/040920-272.1 -
The Journal of Thoracic and... Jul 2018
Topics: Aorta; Aortic Valve; Bicuspid; Bicuspid Aortic Valve Disease; Heart Valve Diseases; Humans
PubMed: 29680713
DOI: 10.1016/j.jtcvs.2018.03.076 -
Dental Press Journal of Orthodontics 2021A side effect observed in cases treated with extractions is the instability of orthodontic space closure.
INTRODUCTION
A side effect observed in cases treated with extractions is the instability of orthodontic space closure.
OBJECTIVE
The aim of this study was to investigate the influence of gingival invagination, presence of third molars and facial pattern, on the stability of orthodontic space-closure in the maxillary arch.
METHODS
Ninety-nine subjects (41 male and 58 female) with Class I malocclusion treated with four premolars extraction were evaluated. Extraction sites reopening and gingival invaginations were evaluated in scanned dental models in the posttreatment and 1-year posttreatment stages (mean age 16.1 years). Third molars presence was evaluated at 1-year posttreatment panoramic radiographs, and the facial pattern (SN.GoGn) was evaluated in the initial lateral headfilms. Multiple logistic regression analysis was used to estimate the influence of the aforementioned independent variables on the frequency of extraction space reopening.
RESULTS
Space reopening was observed in 20.20% of the subjects 1-year post-debonding. Gingival invaginations were present in 25.73% of quadrants after debonding and in 22.80% 1-year posttreatment. The mean pre-treatment SN.GoGn was 35.64 degrees (SD=5.26). No significant influence was observed of the three independent variables on the instability of extraction site closure.
CONCLUSIONS
The presence of gingival invaginations, third molars and facial growth pattern do not seem to influence maxillary extraction sites reopening.
Topics: Adolescent; Bicuspid; Female; Humans; Male; Malocclusion, Angle Class I; Maxilla; Orthodontic Space Closure; Tooth Extraction
PubMed: 34008738
DOI: 10.1590/2177-6709.26.2.e2119187.oar -
BMC Oral Health May 2022A thorough understanding of the original root and canal anatomy is a critical technical prerequisite for performing cleaning and shaping treatments. Therefore, this...
Visual inspection of root patterns and radiographic estimation of its canal configurations by confirmation using sectioning method. An ex vivo study on maxillary first premolar teeth.
BACKGROUND
A thorough understanding of the original root and canal anatomy is a critical technical prerequisite for performing cleaning and shaping treatments. Therefore, this research aimed to characterize maxillary first premolar teeth' root morphology and canal architecture.
METHODS
One hundred forty-two extracted human adult maxillary first premolar teeth have been retrieved. The extracted teeth were thoroughly cleaned and irrigated to eliminate any remaining debris or blood. They were then preserved in formalin solution until they were eligible for screening. To begin, a visual examination was employed to ascertain the number of roots and their geometry in each sample. Then, utilizing digital radiography in two plains, mesiodistal and distomesial, to further determine those parameters. Finally, a sectioning technique had been used to have the samples cut mesiodistally into slices to validate the internal root canal architecture and identify the number of root canals and their varieties in accordance with Vertucci's categorization system. The canal layout, the pulp chamber, and the root canals were all highlighted (marked) using a fine tip marker in a permanent orange hue to make the canal features more accessible and accurate to visualize. All of the processes were conducted by two highly qualified dentists. The sample size was estimated statistically using the Sealed Envelope program, and the percentage of each configuration was derived in proportion to the overall sample size in order to establish the percentage of each type in each configuration.
RESULTS
From the 142 teeth examined, 42 (29.57%) had one root, 97 (68.31%) had two roots, and only three premolars (2.12%) had three roots. Concerning canal configurations, 100 teeth (70.43%) had type (IV) canal configuration, followed by 37 teeth (26.05%) had types (V), three teeth (2.12%) had type (VIII), and one tooth (0.70%) for each of type (I) and type (II).
CONCLUSIONS
The anatomical pattern of inspected maxillary first premolars are mainly two rooted and predominantly have a type (IV) canal morphology.
Topics: Adult; Bicuspid; Cone-Beam Computed Tomography; Dental Pulp Cavity; Humans; Maxilla; Radiography, Dental, Digital; Tooth Root
PubMed: 35524244
DOI: 10.1186/s12903-022-02198-y -
Scientific Reports Apr 2022This clinical trial compared the time to complete the levelling and alignment stage with flapless piezocision procedure in the treatment of severe maxillary malocclusion... (Randomized Controlled Trial)
Randomized Controlled Trial
This clinical trial compared the time to complete the levelling and alignment stage with flapless piezocision procedure in the treatment of severe maxillary malocclusion with premolar extraction cases. Two-arm parallel group randomized controlled trial was performed at the Orthodontics Unit of Universiti Sains Malaysia, Malaysia. Sixteen patients with severe anterior maxillary crowding (Little's irregularity index: 7-9 mm) and required bilateral first premolars extraction was recruited. The participants were randomly assigned to a study group according to a simple randomization method using a sealed envelope mentioned about the group name. Both groups were treated with fixed orthodontic appliance using the 0.022-in. slot of McLaughlin Bennett Trevisi prescription brackets. The piezocision group received flapless piezocision corticotomy about 4-5 mm in length and 3 mm depth on the labial mucogingiva between the roots of six anterior teeth. The number of days since treatment started, Little's irregularity index, gingival recession, pocket depth, pulp vitality, patient perception of the pain and satisfaction level were recorded before the treatment, at about 1 month and 2 months post-treatment, and at the completion of the levelling and alignment stage. The overall time to complete levelling and alignment stage was significantly shorter in the piezocision group than the control group (mean difference = 31.5 days, 95% CI 6.5, 56.5; p = 0.018). Greater reduction in Little's irregularity index and faster alignment rate in the first 2 months were found in the piezocision group compared to the control group (p < 0.05). No changes in the gingival recession, pocket depth, and pulp vitality in both groups were observed. Patients who received piezocision surgery experienced no or mild pain and were satisfied with the treatment. Flapless piezocision corticotomy is an effective adjunct that shortens treatment time during levelling and alignment stage without any adverse effects on the teeth and surrounding tissues. It is also painless, acceptable and satisfactory to the patients.Trial registration: ACTRN12621001350819.
Topics: Bicuspid; Gingival Recession; Humans; Malocclusion; Pain; Tooth Movement Techniques
PubMed: 35422071
DOI: 10.1038/s41598-022-09851-0