Cone-beam CT landmark detection for measuring basal bone width: a retrospective validation study.

BACKGROUND: Accurate assessment of basal bone width is essential for distinguishing individuals with normal occlusion from patients with maxillary transverse deficiency who may require maxillary expansion. Herein, we evaluated the effectiveness of a deep learning (DL) model in measuring landmarks of basal bone width and assessed the consistency of automated measurements compared to manual measurements. METHODS: Based on the U-Net algorithm, a coarse-to-fine DL model was developed and trained using 80 cone-beam computed tomography (CBCT) images. The model's prediction capabilities were validated on 10 CBCT scans and tested on an additional 34. To evaluate the performance of the DL model, its measurements were compared with those taken manually by one junior orthodontist using the concordance correlation coefficient (CCC). RESULTS: It took approximately 1.5 s for the DL model to perform the measurement task in only CBCT images. This framework showed a mean radial error of 1.22 ± 1.93 mm and achieved successful detection rates of 71.34%, 81.37%, 86.77%, and 91.18% in the 2.0-, 2.5-, 3.0-, and 4.0-mm ranges, respectively. The CCCs (95% confidence interval) of the maxillary basal bone width and mandibular basal bone width distance between the DL model and manual measurement for the 34 cases were 0.96 (0.94-0.97) and 0.98 (0.97-0.99), respectively. CONCLUSION: The novel DL framework developed in this study improved the diagnostic accuracy of the individual assessment of maxillary width. These results emphasize the potential applicability of this framework as a computer-aided diagnostic tool in orthodontic practice.

Comparative evaluation of transverse width indices for diagnosing maxillary transverse deficiency.

OBJECTIVES: This study aimed to compare and evaluate different transverse width indices for diagnosing maxillary transverse deficiency (MTD), a common malocclusion characterized by uncoordinated dental arches, crossbites, and tooth crowding. MATERIALS AND METHODS: Sixty patients aged 7-12 years were included in the study, with 20 patients diagnosed with MTD and 40 normal controls. Transverse width indices, including maxillary width at the buccal alveolar crest and lingual midroot level, as well as at the jugal process width, were measured. Differences between these indices and their corresponding mandibular indices were used as standardized transverse width indices. The reference range of these indices was determined and evaluated. Receiver operating characteristic (ROC) analysis was performed to evaluate their diagnostic ability. RESULTS: The transverse width indices and standardized transverse width indices of the MTD group were significantly smaller than those of the control group, except for the jugal process width. The evaluation of the reference range and ROC analysis revealed that the difference of the maxillomandibular width at buccal alveolar crest was the most accurate diagnostic method. CONCLUSIONS: The jugal point analysis method may not be suitable for diagnosing MTD. Instead, measuring the difference in maxillomandibular width at the buccal alveolar crest proves to be a more reliable and accurate diagnostic method for MTD.

CAD/CAM design and 3D printing of a personalised rapid palatal expander for maxillary transverse deficiency.

Bone -borne ra pid ma xilla ry expansion appliances can achieve skeletal expansion while avoiding the undesirable dental side effec ts caused by a conventional rapid palatal expansion appliance. Typically, t hese (bone-bo rne appliances) included prefabricated devices, which can have limitations such as inadequate palatal adaptation leading to anch orage los s. In addit ion, a s bone thickness is not accounted for, prefabricated expanders cannot ensure the primary stability of the mini-implants. These disadvantages can be overcom e by customisation. This repor t aims to describe the digital design and three-dimensional printing workflow for constructing a personali sed M iniscrewassisted rapid palatal expansion (pMARPE) and present a case depicting its application in a 27-year-old female with 5.0 mm t ransverse discrepancy b etween the maxilla and the mandible. The result demonstrated that the pMARPE could be manufactured without the need for conventional impre s sion or laborator y p rocedures and effec tively e xpanded the palate of an ad ult pat ient with maxillar y transverse deficiency.

A novel maxillary transverse deficiency diagnostic method based on ideal teeth position.

BACKGROUND: This study proposed a novel maxillary transverse deficiency diagnostic method and evaluated the skeletal Class I and the mild skeletal Class III groups. METHODS: Pre-treatment data from 30 mild skeletal Class III and 30 skeletal Class I patients were collected and uploaded to the Emeiqi Case Management System to design the ideal teeth positions. On these positions, the first bi-molars width was measured at the central fossa and center resistance, the maxillary first bi-premolars width was measured at the central fossa, and the mandibular first bi-premolars width was measured at the distal contact point by Mimics, then width differences of two groups were calculated respectively. RESULTS: At ideal teeth positions, there was no statistically significant difference in the maxillomandibular width in the premolar area between the two groups, but there was in the molar area, and this difference was caused by the difference in mandible width between the two groups. CONCLUSIONS: We proposed a new transverse diagnostic method and found that even the Class I group was not quite up to standard in the molar area on ideal teeth positions, and the Class III group had more severe maxillary transverse deficiency than the Class I group. Meanwhile, the maxillary transverse deficiency in the Class III group was mainly caused by the larger width of the mandible.

Short-term outcomes in the upper airway with tooth-bone-borne vs bone-borne rapid maxillary expanders.

BACKGROUND: This study compared the area and minimal section of the nasal cavity, nasopharynx, oropharynx, and hypopharynx in cases treated with different methods of microimplant-assisted expansion. METHODS: Based on a pilot study to calculate the sample size, 30 patients with transverse maxillary deficiency over 14 years of age were retrospectively selected. These patients had received two different types of microimplant-assisted maxillary expansion treatment (MARPE and BAME). The patient underwent Cone-Beam computed tomography (CBCT) before and after treatment (mean time 1.5 months) with MARPE or BAME and upper airway measurements (volume and minimum cross-sectional area) were taken to assess upper airways changes and compare changes between the groups. A paired sample t-test was performed to evaluate the T0-T1 change of airway measurements obtained with MARPE and BAME, and a student t-test to compare changes in airway measurements between MARPE and BAME. RESULTS: This investigation shows a statistically significant increase in total nasopharyngeal airway volume (0.59 ± 1.42 cm3; p < 0.01), total oropharyngeal airway volume (3.83 ± 7.53 cm3; p < 0.01) and minimum oropharyngeal cross-section (53.23 ± 126.46 mm2; p < 0.05) in all cases treated with micro-screw assisted expansion. The minimal cross-sectional area of the oropharynx ((79.12 ± 142.28 mm2; p < 0.05) and hypopharynx (59.87 ± 89.79 mm2; p < 0.05) showed significant changes for cases treated with BAME. As for the comparison between cases treated with MARPE and BAME, no differences in upper airway changes have been observed, except for the minimum cross-sectional area of the nasal cavity, which increases for MARPE (52.05 ± 132.91 mm2) and decreases for BAME (-34.10 ± 90.85 mm2). CONCLUSIONS: A significant increase in total area and minimal section at the level of nasopharynx and oropharynx was observed in cases treated with BAME. Regarding the comparison of MARPE and BAME treatments, no differences were found in the total airway volume and minimal section in upper airway except for the minimum cross section of the nasal cavity that increases for MARPE and decreases for BAME.

Displacement and stress distribution of the craniomaxillofacial complex under different surgical conditions: a three-dimensional finite element analysis of fracture mechanics.

OBJECTIVE: To provide a simplified treatment strategy for patients with maxillary transverse deficiency. We investigated and compared the fracture mechanics and stress distribution of a midline palatal suture under dynamic loads during surgically-assisted rapid palatal expansion. METHODS: Based on the cone-beam computed tomography (CBCT) data of a 21-year-old female volunteer, a three-dimensional model of the cranio-maxillofacial complex (including the palatal suture) was constructed. A finite element analysis model was constructed based on meshwork. After the yield strength of the palatal suture was set, an increasing expansion force (0-500 N) was applied within 140 ms to calculate the time-load curve, which mimicked nonsurgical bone expansion (model A). The same method was used to evaluate the fracture process, time and stress distribution of the palatal suture in maxillary lateral osteotomy-assisted (model B) and LeFort osteomy I (LFIO)-assisted expansion of the maxillary arch (model C). RESULTS: Compared with model A, the palatal suture of model B and model C showed a faster stress accumulation rate and shorter fracture time, and the fracture time of model B and model C was almost identical. Compared with model A, we discovered that model B and model C showed greater lateral extension of the maxilla, and the difference was reflected mainly in the lower part of the maxilla, and there was no difference between model B and model C in lateral extension of the maxilla. CONCLUSIONS: Compared with arch expansion using nonsurgical assistance (model A), arch expansion using maxillary lateral wall-osteotomy (model B) or LFIO had a faster rate of stress accumulation, shorter time of fracture of the palatal suture and increased lateral displacement of the maxilla. Compared with arch expansion using LFIO (model C), arch expansion using lateral osteotomy (model B) had a similar duration of palatal suture rupture and lateral maxillary extension. In view of the trauma and serious complications associated with LFIO, maxillary lateral wall-osteotomy could be considered a substitute for LFIO.

Changes of the upper airway and bone in microimplant-assisted rapid palatal expansion: A cone-beam computed tomography (CBCT) study.

OBJECTIVE: To evaluate the changes of maxillary expansion and upper airway structure after microimplant assisted rapid palatal expansion (MARPE) using cone-beam computed tomography (CBCT). METHODS: This retrospective study included 19 subjects (15 females and 4 males) aged 15-29 years old (mean, 19.95±4.39 years) with maxillary transverse deficiency treated with MARPE. CBCT was performed at the initial diagnosis and 3 months after MARPE treatment. Measurements were taken to evaluate the amount of total expansion, skeletal expansion, and dental expansion at the maxillary first premolar (P1), second premolar (P2), first molar (M1), second molar (M2) regions and upper airway changes. RESULTS: After MARPE treatment, the maxillary skeletal base expansion, skeletal expansion, alveolar expansion and dental expansion were achieved at the P1, P2, M1, M2 region. The nasopharyngeal volume significantly increased 8.48% after MARPE treatment compared with that before the treatment (P < 0.05). The change of nasal lateral width (NLW) was also significantly different before and after MARPE (P < 0.05). However, there were no statistically significant change in the oropharyngeal, palatopharyngeal, glossopharyngeal and airway total volume (all P > 0.05). CONCLUSIONS: MARPE can produce more transverse bone expansion, relieve maxillary transverse deficiency and improve upper airway ventilation.

Comparing the effects of three different fluoride-releasing agents on white spot lesion prevention in patients treated with full coverage rapid maxillary expanders.

OBJECTIVE: The aim of this study was to assess the effects of three different fluoride-releasing agents on preventing white spot lesions that occur during treatment with full coverage rapid maxillary expanders. MATERIALS AND METHODS: A total of 48 patients with transverse maxillary deficiency were randomly assigned to four equal groups. A fluoride-containing agent was applied to teeth before cementation of the full coverage acrylic-bonded rapid maxillary expanders in the three experimental groups (gel, varnish, and sealent in groups 1, 2, and 3, respectively), while the control group received no agent application. Quantitative light-induced fluorescence (QLF) images of the patients were obtained before cementation and after decementation of the appliances. Four parameters (ΔF, ΔFmax, A, and ΔR) were evaluated on maxillary ten anterior teeth. RESULTS: In the fluoride gel group, upper central and lateral incisors, right first and left second premolars showed significant decreases in fluorescence levels indicating demineralization. Right central and left lateral incisors showed significant white spot lesion formation in the fluoride varnish group. Right and left central incisors and left first premolar were the teeth that mineral loss was observed in the sealent group, while all of the teeth except canines and first premolars showed significant demineralization in the control group. CONCLUSIONS: Multifluorid varnish and Proseal sealant were effective on preventing demineralization and should be applied to teeth clinically before appliance cementation. CLINICAL RELEVANCE: Demineralization is a major problem during orthodontic treatment. The application of effective fluoride-releasing agents could prevent this major iatrogenic complication.

A skeletal Class III young adult with severe maxillary transverse deficiency treated with maxillary skeletal expander.

This case report describes correction of maxillary constriction using a maxillary skeletal expander (MSE) in a 15-year-old female with a skeletal Class III pattern and asymmetry. The maxillary expansion device with four mini-implants was used to correct the constricted maxilla, bilateral crossbite of the posterior teeth, and crowding of the dentition. Comparison of cone-beam computed tomography scans before and after treatment showed that the majority of maxillary expansion was orthopedic, with minimal alveolar bone bending and tooth tipping. Fixed appliances were used to correct the crowding and malocclusion. Stable and satisfactory maxillary expansion was obtained by using MSE non-urgically.

An adult case of unilateral posterior crossbite caused by maxillary transverse deficiency treated with miniscrew-assisted rapid palatal expansion.

This report describes the successful treatment of an adult case of unilateral posterior crossbite caused by maxillary transverse deficiency with miniscrew-assisted rapid palatal expansion (MARPE). A female patient aged 35.5 years presented with masticatory disturbance, facial asymmetry, and unilateral posterior crossbite. She was diagnosed with unilateral posterior crossbite with a skeletal Class III jaw-base relationship and high mandibular plane angle. Her maxillary right and mandibular bilateral second premolars were congenitally absent, and the maxillary left second premolar was impacted. After the improvement of the posterior crossbite with MARPE, 0.018″ slot lingual brackets were placed on the maxillary and mandibular dentition. The total active treatment period was 22 months, and acceptable occlusion with a functional Class I relationship was achieved. Pretreatment and posttreatment cone-beam computed tomography images showed the disarticulation of the midpalatal suture after MARPE, and changes in the dental and nasomaxillary structures, nasal cavity, and pharyngeal airway. The case results demonstrate that MARPE produces greater skeletal expansion with minimal buccal tipping of the molars. MARPE may be effective for the treatment of maxillary transverse deficiency in adult patients.