Summary
Objectives
To investigate mandibular morphology in adults affected by posterior unilateral crossbite (PUXB) and to evaluate the hemi mandibular volumes from the crossbite (CB) and non-CB sides of the same patients.
Methods
Thirty-eight cone beam computed tomography (CBCT) images were consecutively recruited and the Digital Imaging and Communications in Medicine (DICOM)-formatted scans were volume rendered into a surface three-dimensional (3D) mesh model and volumes to obtain the 3D model of the mandibular bone. To achieve the surface point-to-point analysis of the mandibular models, a reverse engineering software was used. The same procedure was performed for an age-matched control group (19 CBCT images).
Results
Total mandibular volume showed a difference of 2.46 cm3 between patients and controls, which was not statistically significant. A mean difference of 1.53 cm3 was found comparing the hemi mandibular volumes from the CB and non-CB sides of PUXB patients, this difference was statistically significant (P ≤ 0.01). Findings for the surface-to-surface deviation analysis, demonstrated a higher percentage of mismatch in patients PUXB, over 10% at 0.5 mm tolerance level.
Limitations
Limitations are related to the intrinsic surfaces matching methodology, that make difficult to evaluate discrepancies among different mandibular anatomical units.
Conclusion
Adult patients affected by PUXB show a greater mandibular structural asymmetry compared to controls because of a lower matching percentage obtained from the surface-to-surface matching technique.
Implications
Treatment of adult patients affected by PUXB should take into consideration the possibility of a mild mandibular asymmetry mainly localized at the condyle and gonial angle levels.
Objectives
To compare, using surface-to-surface (StS) matching, any shape differences between the crossbite and noncrossbite side of the glenoid fossa and articular eminence in adult patients affected by posterior unilateral crossbite (PUXB) and compare them with unaffected controls.
Materials and Methods
32 cone beam computed tomography (CBCT) scans of patients (mean age: 23.72 ± 3.74 years) undergoing surgical maxillary expansion were analyzed to obtain three-dimensional models of the left and right glenoid fossae that were superimposed using stable anatomical reference points and then compared using StS matching to evaluate the presence of any shape differences. These findings were compared with those obtained from 16 CBCT scans of unaffected controls (mean age: 23.72 ± 3.73 years).
Results
A mean difference of >11% was found between the study group and controls when comparing the matching percentages of the two sides of the glenoid fossa and articular eminence at all three levels of tolerance selected for this study. These differences were found to be highly statistically significant (P ≤ .0001).
Conclusions
According to the shape analysis findings, adult PUXB patients exhibit a higher degree of glenoid fossa and articular eminence shape differences compared to unaffected controls.
The purpose of our work is to evaluate the correlation between skeletal Class II malocclusion and temporomandibular disorders, by assessing potential different frequency scores compared with Class I and Class III skeletal malocclusion, and to evaluate associated etiological and risk factors. Fifty-five subjects were examined, 35 females and 20 males, with a mean age of 18 ± 1.3 years, divided into two groups: those with TMD and those without TMD, and prevalence was evaluated in the two groups of Class II subjects. Symptoms and more frequent signs were also examined in the TMD group. Regarding Group A (subjects with the presence of TMD), we found that 48% have a Class II, 16% have Class I, and 28% have Class III. In the totality of the group A sample, only 8% were male subjects. In Group B (subjects without TMD), we found that 40% were females, with 26.7% in Class I, 10% in Class II, and 3.3% in Class III; the male subjects in this group (60%) were distributed with 33.3% in Class I, 16.7% in Class II, and 10% in Class III. Class II malocclusion is not a causal factor of TMD but may be considered a predisposing factor.
Background
The aim of this investigation is to evaluate the feasibility of digital workflow for lingual fixed retainer based on digital intraoral scan and appliance production from Polyetheretherketone (PEEK) material for clinical consideration.
Material and Methods
Fully virtual lingual retainer with bilateral missing lateral incisors was designed using inlab software (Dentsply Sirona, Pennsylvania, USA). The designed retainer was produced in PEEK material and clinically adhered to lingual surfaces of the lower front teeth.
Results
Lingual retainer was successfully fabricated by full digital workflow and produced from PEEK material for clinical usage.
Conclusions
Although full digital workflow can be clinically used for production of prefabricated lingual retainer, however further software adaptions are required for improvement of the orthodontic workflow.
Key words:
PEEK, CAD/CAM, digital orthodontics, lingual retainer.
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