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Progress in Orthodontics Dec 2023The aim of this study was to evaluate the distal movement, vertical movement, distal tipping and crown buccal torque of maxillary molars after the completion of...
BACKGROUND
The aim of this study was to evaluate the distal movement, vertical movement, distal tipping and crown buccal torque of maxillary molars after the completion of distalization by comparing the predicted movement with the achieved movement using palatal rugae registration.
METHODS
The study included 22 clear aligner patients (7 males and 15 females), and 79 molars were measured. Two digital models were generated before treatment and after molar distalization and were superimposed after selecting the palatal rugae area for registration in GOM inspect suite software 2022 (GOM; Braunschweig, Germany). The predicted and achieved movements of molar distalization, intrusion, distal tip and crown buccal torque were measured and compared.
RESULT
The achieved distalization (1.25 ± 0.79 mm vs. 2.17 ± 1.03 mm, P < 0.001; 1.41 ± 1.00 mm vs. 2.66 ± 1.15 mm, P < 0.001), intrusion (0.47 ± 0.41 mm vs. 0.18 ± 0.54 mm, P < 0.01; 0.58 ± 0.65 mm vs. 0.10 ± 1.12 mm, P < 0.01), distal tip (5.30 ± 4.56° vs. 1.53 ± 2.55°, P < 0.001; 4.87 ± 4.50° vs. - 1.95 ± 4.32°, P < 0.001) and crown buccal torque (1.95 ± 4.18° vs. - 1.15 ± 4.75°, P < 0.001; 0.43 ± 4.39° vs. - 4.27 ± 6.42°, P < 0.001) were significantly different from the predicted values in the two groups (first molar, second molar). Significant regression relationships were found between the achieved distal movement and deviational intrusion (R = 0.203, P < 0.0001), distal tip (R = 0.133, P < 0.001) and crown buccal torque (R = 0.067, P < 0.05). There was a significant correlation between the deviational movements of intrusion and the distal tip (R = 0.555, P < 0.0001).
CONCLUSION
Approximately 2 mm maxillary molar distalization was achieved in this study. Deviational movement of intrusion, distal tip and crown buccal torque beyond the clear aligner virtual design appeared to a certain degree after distalization. Thus, more attention should be given to molar intrusion and distal tip and crown buccal torque as the designed distalization increases.
Topics: Male; Female; Humans; Torque; Malocclusion, Angle Class II; Maxilla; Molar; Crowns; Orthodontic Appliances, Removable; Tooth Movement Techniques
PubMed: 38151662
DOI: 10.1186/s40510-023-00500-4 -
International Journal of Oral Science Feb 2024Mammalian teeth, developing inseparable from epithelial-mesenchymal interaction, come in many shapes and the key factors governing tooth morphology deserve to be...
Mammalian teeth, developing inseparable from epithelial-mesenchymal interaction, come in many shapes and the key factors governing tooth morphology deserve to be answered. By merging single-cell RNA sequencing analysis with lineage tracing models, we have unearthed a captivating correlation between the contrasting morphology of mouse molars and the specific presence of PRX1 cells within M1. These PRX1 cells assume a profound responsibility in shaping tooth morphology through a remarkable divergence in dental mesenchymal cell proliferation. Deeper into the mechanisms, we have discovered that Wnt5a, bestowed by mesenchymal PRX1 cells, stimulates mesenchymal cell proliferation while orchestrating molar morphogenesis through WNT signaling pathway. The loss of Wnt5a exhibits a defect phenotype similar to that of siPrx1. Exogenous addition of WNT5A can successfully reverse the inhibited cell proliferation and consequent deviant appearance exhibited in Prx1-deficient tooth germs. These findings bestow compelling evidence of PRX1-positive mesenchymal cells to be potential target in regulating tooth morphology.
Topics: Animals; Mice; Mesenchymal Stem Cells; Molar; Morphogenesis; Tooth Germ
PubMed: 38369512
DOI: 10.1038/s41368-024-00277-0 -
Healthcare (Basel, Switzerland) Jun 2023Mandibular third molar (M3M) removal and the management of postoperative complications represent a common matter of interest in oral and maxillofacial surgery. Pain...
BACKGROUND
Mandibular third molar (M3M) removal and the management of postoperative complications represent a common matter of interest in oral and maxillofacial surgery. Pain represents a great symptom for patients affected by pericoronitis and it is the most common indication for third molar removal. The aim of the present article is to search for patterns of pre-operative pain in patients before undergoing third molar surgery and to test for a relation between some patterns of symptoms, such as pain intensity, site of symptomatic tooth, and referred area of pain.
METHODS
This retrospective observational study enrolled a total of 86 patients, aged (mean ± SD) 34.54 ± 13.62 years (range 17-78 years), scheduled for outpatient third molar extraction at the Oral Surgery School, Department of Medical Biotechnologies, Policlinico "Le Scotte", University of Siena. Pericoronitis and pain were the symptoms of the patients and the indication of extraction. Inclusion criteria were the presence of partially impacted third molars, confirmed with a preoperative panoramic radiograph, and preoperative pain. Exclusion criteria were known neurological disease (such as previous trigeminal or facial nerve injuries), impaired communicative or cognitive disease, diagnosed diabetes mellitus, and oral surgical intervention within 30 days before data collection. Patients were visited and asked to answer a morphometric analytic questionnaire about their perception of pain referred to the third molar. Analyses were performed on statistical evaluation on age, age ranges, patient gender, prior third molar extraction, site of pericoronitis, pain score (1-10), and pain area. Two-tailed values of less than 0.05 were considered significant if not otherwise specified.
RESULTS
No correlations were found between age, gender, previous extraction, tooth site (maxillar on mandible), pain score, and pain area. Patterns of third molar pericoronitis pain among 86 patients were reported. A significant correlation was found between pain score and pain area ( = 0.0111, = 0.3131).
CONCLUSIONS
Pain intensity has indeed some kind of responsibility in determining the orofacial distribution of pain. The pain area referral patterns of the present article could be considered as a pain model resulting from the pericoronitis of maxillar and mandibular third molars.
PubMed: 37444724
DOI: 10.3390/healthcare11131890 -
BioMed Research International 2023It is essential to be aware of the potential effects of orthodontic treatment on tissues and anatomical structures associated with the masticatory system, especially the...
OBJECTIVE
It is essential to be aware of the potential effects of orthodontic treatment on tissues and anatomical structures associated with the masticatory system, especially the temporomandibular joint (TMJ). Little information is available about the consequences of molar distalization on the TMJ. Therefore, this study is aimed at investigating the changes of the condyle-fossa relationship after molar distalization using the distal jet appliance.
MATERIALS AND METHODS
The sample consisted of twenty-five patients (mean age 20.4 ± 2.6) who underwent molar distalization by the distal jet appliance. CBCT scans were taken before (T0) and after (T1) the completion of the molar distalization. Joint spaces (anterior, superior, and posterior) and cephalometric vertical angles (SN.GOME and Björk sum) were measured and compared at T0 and T1.
RESULTS
Superior and posterior joint spaces increased significantly after molar distalization (PS 0.29 mm, < 0.001, SS 0.06 mm, < 0.5). Vertical cephalometric angles also increased after molar distalization by the distal jet appliance (SN.GOME 0.92°, Björk 1.11°).
CONCLUSION
There was a statistically significant increase in the superior and posterior joint spaces after molar distalization. However, this increase may not be of clinical importance. The vertical dimension has also increased.
Topics: Humans; Adolescent; Young Adult; Adult; Malocclusion, Angle Class II; Glenoid Cavity; Maxilla; Temporomandibular Joint; Molar; Cephalometry; Tooth Movement Techniques
PubMed: 37409266
DOI: 10.1155/2023/5549951 -
BMC Oral Health Nov 2023To observe the three-dimensional positional relationship between impacted mandibular third molars (IMTMs) and mandibular canal close contacts using cone beam computed...
OBJECTIVE
To observe the three-dimensional positional relationship between impacted mandibular third molars (IMTMs) and mandibular canal close contacts using cone beam computed tomography (CBCT).
METHODS
A total of 101 patients with IMTMs were selected who met the diagnostic criteria for 142 teeth (no bone wall imaging area between IMTMs and the mandibular canal, a high-density bone cortical imaging area only, or a ≦1 mm bone imaging area). The parameters of the rotating CBCT anode were set as follows: 110 kV, 40-50 mA; the focal point and exposure field were set as 0.3 mmh and a high-resolution zoom, respectively; the exposure time and image layer thickness were set as 5.4 s and 0.25 mm. Three-dimensional reconstruction was performed, and the position of the mandibular canal through the IMTM area was observed continuously from the coronal, horizontal and sagittal planes.
RESULTS
We found that the mandibular canal was interrupted below the third molar (TM) in 85 cases, accounting for 59.86% of all cases. The mandibular canal was located below the buccal and lingual curvatures in 33 and 19 cases, respectively, accounting for 23.23% and 19%. In addition, a small number of mandibular canals were also located on the buccal side of the mandibular molars (2.82%). We also found one case of direct insertion of the mandibular third molar (MTM) into the mandibular canal. In addition, the mandibular canal passed through the IMTM region with 125 close contacts at the roots (88.03%); 14 mandibular canals were in contact with all teeth and 3 were in contact with the crown.
CONCLUSION
The use of CBCT can provide a dynamic and comprehensive understanding of the three-dimensional positional relationship of the mandibular alveolar nerve canal passing through the IMTM area, providing a high clinical reference value when extracting IMTMs and reducing the risk of injury to the inferior alveolar nerve.
Topics: Humans; Molar, Third; Mandibular Canal; Molar; Mandible; Tooth, Impacted; Cone-Beam Computed Tomography; Mandibular Nerve
PubMed: 37924035
DOI: 10.1186/s12903-023-03548-0 -
BMC Oral Health Oct 2023The extraction of impacted mandibular third molars might cause large bone defects in the distal area of second molars. A new strategy was innovatively employed here... (Randomized Controlled Trial)
Randomized Controlled Trial
A novel concentrated growth factor (CGF) and bio-oss based strategy for second molar protection after impacted mandibular third molar extraction: a randomized controlled clinical study.
BACKGROUND
The extraction of impacted mandibular third molars might cause large bone defects in the distal area of second molars. A new strategy was innovatively employed here combining autologous bone, Bio-Oss, concentrated growth factors (CGF) gel and CGF membrane for bone repair, and the present study aimed at exploring safety as well as short- and long-term efficacy of this new protocol clinically.
MATERIALS AND METHODS
A total of 66 participants were enrolled in this randomized single-blind clinical trial, and randomly allocated to control group (only blood clots), test A group (autogenous bone, Bio-Oss with barrier membrane) and test B group (autogenous bone, Bio-Oss, CGF gel with CGF membrane). The postoperative outcomes including PoSSe scale, periodontal probing depth (PD), degree of gingival recession and computed tomography measurements were assessed at 3rd, 6th, 12th month. A p-value < 0.05 was considered statistically significant.
RESULTS
In PoSSe scale, no significant difference was observed except a significant alleviation of early-stage pain perception in test B group (p < 0.05). Also, test B group exhibited better effect on periodontal healing and gingival recession reduction after 6 months (p < 0.05). Both two test groups showed more new bone formation than the control group (p < 0.05). It is noteworthy that the bone repair of test B group was significantly better than that of test A at 3rd and 6th month (p < 0.05), yet no difference was observed at 12th month (p > 0.05).
CONCLUSION
Both two test groups could achieve stable long-term efficacy on bone defect repair. The use of CGF gel and CGF membrane could accelerate early-stage bone repair, alleviate short-term pain after surgery, reduce long-term probing depth and relieve economic cost for patients. This new bone repair protocol is worthy of promoting by clinicians.
TRIAL REGISTRATION
This study was registered with the identification number ChiCTR2300068466 on 20/02/2023 at Chinese Clinical Trial Registry. Also, it was ethically approved from the institutional ethics committee at the Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China (No:2023-010-01), and has been conducted in accordance to the guidelines of the declaration of Helsinki. Written informed consent was obtained from all participants in the study.
Topics: Humans; Molar, Third; Gingival Recession; Single-Blind Method; Tooth Extraction; China; Molar; Tooth, Impacted; Mandible; Intercellular Signaling Peptides and Proteins
PubMed: 37828455
DOI: 10.1186/s12903-023-03411-2 -
BMC Oral Health Jul 2023Establishing the level of surgical difficulty pre-operatively is an essential step in ensuring correct treatment planning. This study set out to determine whether the... (Observational Study)
Observational Study
BACKGROUND
Establishing the level of surgical difficulty pre-operatively is an essential step in ensuring correct treatment planning. This study set out to determine whether the knowledge and experience acquired by dentists who had received different levels of training influenced, firstly, the perceived levels of difficulty of a variety of cases of mandibular third molar (MTM) extraction and, secondly, the perceived difficulty deriving from a series of factors (patient-related factors, anatomical and radiographic factors, operative factors).
METHODS
This cross-sectional, descriptive, observational study took the form of a survey. Using a visual analog scale (VAS), participants evaluated both the perceived difficulty of 30 cases of MTM extraction described by means of digital panoramic radiographs and the perceived difficulty deriving from a series of factors conditioning MTM extraction. The results underwent statistical analysis with SPSS Statistics 28.0 software. Non-parametric tests (Mann Whitney test for independent samples and the Kruskal-Wallis test) were applied.
RESULTS
A total of 389 surveys were available for analysis. Dental practioners with no surgical training saw the intervention as presenting greater difficulty. Professionals with postgraduate training in oral surgery considered patient-related factors more important than operative factors, in contrast to dentists who had not received oral surgery training.
CONCLUSIONS
Dental training has a signficant influence on the perceived difficulty of MTM extraction and also affects opinions about which factors have greater or lesser influence on surgical difficulty.
Topics: Humans; Molar, Third; Cross-Sectional Studies; Tooth Extraction; Surveys and Questionnaires; Research Design; Mandible; Tooth, Impacted
PubMed: 37452399
DOI: 10.1186/s12903-023-03131-7 -
Journal of Orthodontics Mar 2024The primary aim of this study was to provide a review of the types and frequency of orthodontic brackets, molar bands and orthodontic auxiliaries used for patients... (Review)
Review
OBJECTIVE
The primary aim of this study was to provide a review of the types and frequency of orthodontic brackets, molar bands and orthodontic auxiliaries used for patients undergoing orthognathic surgery. The secondary aim was to evaluate the risk of failure of these items during orthognathic surgery.
METHODS
From three Dutch hospitals, 124 adult patients were included in this prospective cohort study. Five independent researchers collected the data during surgery using a specifically created data extraction form. The type of surgery, surgeon, orthodontist and type of orthodontic bracket, molar band or auxiliary were noted for each tooth. To evaluate their failure risk, the following variables were noted: failure and site; and type and cause of failure.
RESULTS
Stainless-steel brackets were the most frequently (75.8%) used bracket type seen in patients undergoing orthognathic surgery. Ceramic brackets were seen in 24.2% of the cases and were only applied in the anterior region. Molar bands were present in 58.9% of the patients and mostly with bands on the first molars in combination with bonded tubes on the second molars. In 32.2% of all cases, one or more failures were noted. One-third of all failures were described as detachment of the molar tube on the most posterior molar. Kobayashi ligatures and powerpins showed the highest risk of failure (odds ratio [OR] 3.70, 95% confidence interval [CI] = 1.91-7.15). No significant difference in failure rate was found between stainless-steel brackets, molar bands (OR 0.34, 95% CI = 0.08-1.43) and ceramic brackets (OR 0.44, 95% CI = 0.14-1.45).
CONCLUSION
Stainless-steel brackets, ceramic brackets, molar bands and surgical hooks are suitable for orthognathic cases. Kobayashi ligatures and powerpins had a significantly higher risk of failure so are not recommended for temporary intraoperative maxillomandibular fixation (TIO-MMF).
Topics: Adult; Humans; Orthognathic Surgery; Orthodontic Brackets; Prospective Studies; Molar; Steel; Orthodontic Wires; Stainless Steel; Orthodontic Appliance Design
PubMed: 37462079
DOI: 10.1177/14653125231186825 -
Clinical Oral Investigations Jun 2024We aimed to evaluate changes in the zygomatic pillar during orthodontic treatment involving premolar extraction, analyze the effects of maxillary first molar movement on...
OBJECTIVE
We aimed to evaluate changes in the zygomatic pillar during orthodontic treatment involving premolar extraction, analyze the effects of maxillary first molar movement on zygomatic pillar remodeling, and examine occlusal characteristics and stress distribution after remodeling.
METHODS
Twenty-five patients who underwent premolar extraction were included in the study. The zygomatic pillar measurement range was defined, and cross-sectional areas, surface landmark coordinates, alveolar and cortical bone thicknesses, and density changes were assessed using Mimics software based on the cone-beam computed tomography scans taken before (T0) and after the treatment (T1). Multiple linear regression analysis was performed to determine the correlation between changes in the zygomatic pillar and maxillary first molar three-dimensional (3D) movement and rotation. Additionally, the correlation between pillar remodeling and occlusal characteristics was analyzed by Teetester. Pre- and post-reconstruction 3D finite element models were constructed and loaded with an average occlusal force of two periods.
RESULTS
The morphological and structural remodeling of the zygomatic pillar after orthodontic treatment involving premolar extraction showed a decreased cross-sectional area of the lower segment of the zygomatic pillar. The zygomatic process point moved inward and backward, whereas the zygomatico-maxillary suture point moved backward. The thicknesses of the zygomatic pillar alveolar and cortical bones were thinner, and reduced alveolar bone density was observed. Simultaneously, the movement and angle change of the maxillary first molar could predict zygomatic pillar reconstruction to a certain extent. With decreasing the total occlusal force and the occlusal force of the first molar, occlusal force distribution was more uniform. With zygomatic pillar remodeling, occlusal stress distribution in the zygomatic alveolar ridge decreased, and occlusal stress was concentrated at the junction of the vertical and horizontal parts of the zygomatic bone and the posterior part of the zygomatic arch.
CONCLUSIONS
Orthodontic treatment involving premolar extraction led to zygomatic pillar remodeling, making it more fragile than before and reducing the occlusal force of the maxillary first molar and the entire dentition with stress concentrated in weak areas.
CLINICAL RELEVANCE
No other study has focused on the effects of orthodontics on pillar structures. The present study indicates that the mesial movement of the maxillary first molar weakened the zygomatic pillar and reduced occlusal function, thereby providing insights for inserting anchorage screws and facial esthetics.
Topics: Humans; Zygoma; Cone-Beam Computed Tomography; Tooth Movement Techniques; Female; Male; Molar; Finite Element Analysis; Bicuspid; Maxilla; Tooth Extraction; Imaging, Three-Dimensional; Adolescent; Bone Remodeling; Dental Stress Analysis; Adult; Young Adult
PubMed: 38878070
DOI: 10.1007/s00784-024-05713-3 -
Dental Press Journal of Orthodontics 2023To explore the association between chronological, dental and skeletal ages and early diagnosis of third molars agenesis.
OBJECTIVE
To explore the association between chronological, dental and skeletal ages and early diagnosis of third molars agenesis.
MATERIAL AND METHODS
This retrospective radiographic study comprised a sample of 282 Portuguese patients (122 males and 160 females) who sought orthodontic treatment between 2007 and 2018. Each participant had panoramic and lateral cephalometric radiographs performed before and after the age of 14 years. The chronological age was categorized into three intervals between 11.0 and 13.11 years of age. The full eruption of the four-second molars was used as a criterion in determining dental age. Skeletal age was verified by the vertebral maturation method. The diagnosis of agenesis of third molars was initially performed by observation of the initial panoramic radiography undertaken before the age of 14 years. Subsequently, the diagnosis of agenesis of third molars was confirmed by visualizing the second panoramic radiography, obtained after the age of 14 years. The association between the accuracy of the diagnosis and the chronological, dental and skeletal ages was evaluated using the chi-square test, at a 5% significance level.
RESULTS
No significant association between chronological age and alterations in the diagnosis of third molar agenesis was identified. However, there was a significant association between third molar agenesis and both dental age (p<0.001) and skeletal age (p=0.006).
CONCLUSION
The eruption of the four-second molars and the peak of growth could be considered as criteria for early diagnosis of third molar agenesis, whereas chronological age is not a reliable diagnostic indicator.
Topics: Male; Female; Humans; Adolescent; Child, Preschool; Molar, Third; Retrospective Studies; Molar; Anodontia; Radiography, Panoramic; Early Diagnosis
PubMed: 37466505
DOI: 10.1590/2177-6709.28.3.e2321322.oar