Ultrasonic mapping of midpalatal suture - An ex-vivo study.

OBJECTIVE: Rapid maxillary expansion is a common orthodontic procedure to correct maxillary constriction. Assessing the midpalatal suture (MPS) expansion plays a crucial role in treatment planning to determine its effectiveness. The objectives of this preliminary investigation are to demonstrate a proof of concept that the palatal bone underlying the rugae can be clearly imaged by ultrasound (US) and the reconstructed axial view of the US image accurately maps the MPS patency. METHODS: An ex-vivo US scanning was conducted on the upper jawbones of two piglet's carcasses before and after the creation of bone defects, which simulated the suture opening. The planar images were processed to enhance bone intensity distribution before being orderly stacked to fuse into a volume. Graph-cut segmentation was applied to delineate the palatal bone to generate a bone volume. The accuracy of the reconstructed bone volume and the suture opening was validated by the micro-computed tomography (µCT) data used as the ground truth and compared with cone beam computed tomography (CBCT) data as the clinical standard. Also included in the comparison is the rugae thickness. Correlation and Bland-Altman plots were used to test the agreement between the two methods: US versus µCT/CBCT. RESULTS: The reconstruction of the US palatal bone volumes was accurate based on surface topography comparison with a mean error of 0.19 mm for pre-defect and 0.15 mm and 0.09 mm for post-defect models of the two samples, respectively when compared with µCT volumes. A strong correlation (R2 ≥ 0.99) in measuring MPS expansion was found between US and µCT/CBCT with MADs of less than 0.05 mm, 0.11 mm and 0.23 mm for US, µCT and CBCT, respectively. CONCLUSIONS: It was possible to axially image the MPS opening and rugae thickness accurately using high-frequency ultrasound. CLINICAL SIGNIFICANCE: This study introduces an ionizing radiation-free, low-cost, and portable technique to accurately image a difficult part of oral cavity anatomy. The advantages of conceivable visualization could promise a successful clinical examination of MPS to support the predictable treatment outcome of maxillary transverse deficiency.

Development and initial validation of a questionnaire to measure patient experience with oral appliance therapy.

STUDY OBJECTIVES: To develop and validate a questionnaire to measure patient experience with oral appliance therapy. METHODS: The AMEE Guide No. 87 was followed in the development and validation of a patient questionnaire to assess patient experience with oral appliance therapy. RESULTS: Our search identified 522 articles; 5 of these articles described the use and/or validation of questionnaires to measure changes in symptoms and patient-reported outcomes in the treatment of obstructive sleep apnea. A total of 27 questions were developed. Five patients participated in pilot testing. A final review of the questionnaire was conducted by an expert panel. CONCLUSIONS: The creation and validation of a questionnaire to assess patient experience with oral appliance therapy may provide new methods for advancing research in the field of dental sleep medicine. CITATION: Ng ET, Perez-Garcia A, Lagravère-Vich MO. Development and initial validation of a questionnaire to measure patient experience with oral appliance therapy. J Clin Sleep Med. 2023;19(8):1437-1445.

The three-dimensional stable mandibular landmarks in patients between the ages of 12.5 and 17.1 years.

BACKGROUND: With the aid of implants, Björk identified two-dimensional mandibular stable structures in cephalograms during facial growth. However, we do not know what the three-dimensional stable structures are with certainty. The purpose of this study was to identify the most stable mandibular landmarks in growing patients using three-dimensional images. METHODS: The sample was comprised of two cone-beam computed tomography (CBCT) scans taken about 4.6 years apart in 20 growing patients between the ages of 12.5 (T1) and 17.1 years (T2). After head orientation, landmarks were located on the chin (Pog), internal symphysis (Points C, D and E), and mandibular canals, which included the mental foramina (MF and MFA) and mandibular foramina (MdF). The linear distance change between Point C and these landmarks was measured on each CBCT to test stability through time. The reliability of the suggested stable landmarks was also evaluated. RESULTS: The total distance changes between Point C and points D, E, Pog, MF, and MFA were all less than 1.0 mm from T1 to T2. The reliability measures of these landmarks, which were measured by the Cronbach alpha, were above 0.94 in all three dimensions for each landmark. From T1 to T2, the distance changes from Point C to the right and left mandibular foramina were 3.39 ± 3.29 mm and 3.03 ± 2.83 mm, respectively. CONCLUSIONS: During a growth period that averaged 4.6 years, ranging from 11.2 to 19.8 years old, the structures that appeared relatively stable and could be used in mandibular regional superimpositions included Pog, landmarks on the inferior part of the internal symphysis, and the mental foramen. The centers of the mandibular foramina and the starting points of the mandibular canal underwent significant changes in the transverse and sagittal dimensions.

Growth changes in the anterior and middle cranial bases assessed with cone-beam computed tomography in adolescents.

INTRODUCTION: Initially, cone-beam computed tomography images from dry skulls were used to 3 dimensionally evaluate intrarater and interrater reliabilities and accuracy of selected 3-dimensional landmarks located in the anterior and middle cranial bases. Thereafter, dimensional changes of the anterior and middle cranial bases with growth were evaluated by using the previously selected landmarks. METHODS: Cone-beam computed tomography images of 10 dry skulls were used to identify useful landmarks from different areas of the anterior and middle cranial bases based on their reliability and accuracy. These selected landmarks were identified in the images of an already available sample of adolescents (n = 60) taken at 2 time points (19 months apart) to assess dimensional changes with growth. RESULTS: The majority of the proposed 3-dimensional landmarks with the exception of the lesser wing of the sphenoid showed acceptable intrarater and interrater reliabilities. The distances measured between foramina and canals in the transverse dimension showed evidence of increases in size. However, the mean amounts of increase in these transverse distances were equal to or less than 1.05 mm (from 1.1% to 4.1%). No change was observed between the right and left anterior and posterior clinoid processes. The vertical dimensions showed evidence of some changes, but these were within 2% of the original distances. CONCLUSIONS: In this adolescent sample, minor growth-related changes were observed in the anterior and middle cranial bases. The midsagittal area of the anterior cranial base (foramen caecum to presphenoid) was stable. The right and left anterior and posterior clinoid processes can be used for transverse superimposition.

Three-dimensional cephalometric superimposition of the nasomaxillary complex.

INTRODUCTION: Two-dimensional maxillary superimposition techniques have been routinely used in clinical practice, but a 3-dimensional plane has yet to be introduced and validated. The purposes of this study were to propose a new plane for regional superimposition of the maxillary complex and then to validate it through clinical data. METHODS: Pretreatment and posttreatment palatal expansion records were used. The magnitudes of the transverse expansion at the levels of the first premolars and the first molars were assessed using the proposed superimposition plane and then were compared with the gold standard plaster model measurements. Descriptive statistics and agreement testing were performed to compare the methods. RESULTS: When comparing the superimposition and plaster measurement methods, the mean errors for intermolar and interpremolar distances were 0.57 and 0.59 mm, respectively. Both the intraclass correlation coefficient and the Bland-Altman plot demonstrated high agreement between the 2 methods (intraclass correlation coefficient greater than 0.9). CONCLUSIONS: The proposed maxillary superimposition plane yields clinically suitable results when compared with the gold standard technique, with a mean error of less than 0.6 mm for typical intra-arch measurements. This new landmark-derived maxillary plane for superimposition is a promising tool for evaluating maxillary dentoalveolar changes after treatment.

Anterior cranial-base time-related changes: A systematic review.

INTRODUCTION: The anterior cranial base has long been considered a stable reference structure for superimposing radiographs. However, some studies have questioned its stability. Therefore, the purposes of this systematic review were to give an overview of the studies evaluating growth and development of the anterior cranial base, assess their methodologic quality, and evaluate their validity and accuracy. METHODS: Medline, Embase, and Google Scholar were searched without limitations up to June 2013. Additionally, the bibliographies of the finally selected articles were hand searched to identify any relevant publications that were not identified before. The lowest levels of evidence accepted for inclusion were cohort and cross-sectional studies. RESULTS: A total of 11 articles met all inclusion criteria. They were published between 1955 and 2009. The sample sizes of these studies ranged from 28 to 464 subjects. Their methodologic quality ranged from moderate to low. CONCLUSIONS: Sella turcica remodels backward and downward, and nasion moves forward because of the increase in size of the frontal sinus. These events lead to a continuous increase in the length of the cranial base until adulthood. The presphenoid and cribriform plate regions can be considered stable after age 7, making them the best cranial-base superimposition areas.