Exploring the Validity of an Optoelectronic Integrated Cone Beam Computed Tomography Jaw Tracking System.

Jaw motion tracking functionalities of cone beam computed tomography (CBCT)-scanners can visualize, record, and analyze movements of the mandible. In this explorative study, the validity of the 4D-Jaw Motion module (4D-JM) of the ProMax 3D Mid CBCT scanner (Planmeca, Helsinki, Finland) was tested in vitro. The validity of the 4D-JM was accepted if values differed less than 0.6 mm (three voxels sizes) from the gold standard. Three dry human skulls were used. CBCT scans, the gold standard, were taken in eight jaw positions and exported as three-dimensional (3D) models. Individualized 3D-printed dental wafers ensured the correct positioning of the mandible. Jaw positions were recorded with the 4D-JM tracking device and exported as 3D models. The coordinates of six reference points for both superimposed 3D models were obtained. The differences in the x, y and z-axis and the corresponding vector differences between gold standard 3D models and 4D-JM models were calculated. For the mandible 10% and for the maxilla 90% of the vector differences fell within 0.6 mm of the gold standard. With an increasing vertical jaw opening, larger differences between the gold standard and the 4D-JM 3D models were found. The smallest differences of the mandible were observed on the x axis. In this study, the 4D-JM validity was not acceptable by the authors' predefined standards.

Three-dimensional volumetric changes in the airway of growing unilateral complete cleft lip and palate patients after bone-anchored maxillary protraction.

INTRODUCTION: This prospective controlled study evaluates volumetric, length, and average cross-sectional area (aCSA) airway changes in growing patients with unilateral complete cleft lip and palate after 1.5 years of bone-anchored maxillary protraction therapy. METHODS: Thirty-five growing unilateral complete cleft lip and palate patients with maxillary deficiency were included (aged 11.3 ± 0.5 years). Cone-beam computed tomography scans were obtained before bone-anchored maxillary protraction (BAMP) therapy and after 1.5 years. A growing group without cleft (n = 18) patients served as a control group at 1.5 years posttreatment (aged 13.1 ± 1.2 years). Volumetric, length, and aCSA changes of the total airway, nasopharynx (NP), middle pharynx, and inferior pharynx airway were evaluated. RESULTS: After 1.5 years of BAMP therapy, a significant increase was observed in the total airway volume and the NP (P <0.01). The middle and inferior pharynx showed an insignificant tendency of volumetric increase. Compared with the control group, a significantly larger airway volume could be observed in the total airway and NP (P <0.05). The aCSA of the NP increased significantly compared with pretreatment. CONCLUSIONS: The total airway and NP volumes significantly increased in growing subjects with cleft lip and palate after 1.5 years of BAMP therapy to a level comparable to a control group without cleft. Volumetric increase in the NP in the BAMP group is mainly attributed to the increase in its cross-sectional area. BAMP can therefore be recommended as an effective therapy for patients with cleft lip and palate with positive effects on airway development.

Skeletal Changes in Growing Cleft Patients with Class III Malocclusion Treated with Bone Anchored Maxillary Protraction-A 3.5-Year Follow-Up.

This prospective controlled trial aimed to evaluate the skeletal effect of 3.5-years bone anchored maxillary protraction (BAMP) in growing cleft subjects with a Class III malocclusion. SUBJECTS AND METHOD: Nineteen cleft patients (11.4 ± 0.7-years) were included from whom cone beam computed tomography (CBCT) scans were taken before the start of BAMP (T0), 1.5-years after (T1) and 3.5 y after (T2). Seventeen age- and malocclusion-matched, untreated cleft subjects with cephalograms available at T0 and T2 served as the control group. Three dimensional skeletal changes were measured qualitatively and quantitatively on CBCT scans. Two dimensional measurements were made on cephalograms. RESULTS: Significant positive effects have been observed on the zygomaticomaxillary complex. Specifically, the A-point showed a displacement of 2.7 mm ± 0.9 mm from T0 to T2 (p < 0.05). A displacement of 3.8 mm ± 1.2 mm was observed in the zygoma regions (p < 0.05). On the cephalograms significant differences at T2 were observed between the BAMP and the control subjects in Wits, gonial angle, and overjet (p < 0.05), all in favor of the treatment of Class III malocclusion. The changes taking place in the two consecutive periods (ΔT1-T0, ΔT2-T1) did not differ, indicating that not only were the positive results from the first 1.5-years maintained, but continuous orthopedic effects were also achieved in the following 2-years. CONCLUSIONS: In conclusion, findings from the present prospective study with a 3.5-years follow-up provide the first evidence to support BAMP as an effective and reliable treatment option for growing cleft subjects with mild to moderate Class III malocclusion up to 15-years old.

Bone-anchored maxillary protraction in patients with unilateral complete cleft lip and palate and Class III malocclusion.

OBJECTIVE: This prospective controlled study evaluated the effect of bone-anchored maxillary protraction therapy in cleft children with Class III malocclusion using CBCT-derived 3D surface models. MATERIALS AND SUBJECTS: Eighteen cleft patients between 10 and 12 years old were included. Intermaxillary elastics were worn after the placement of four zygoma bone plates for 18 months. Uniquely, three age-matched untreated groups including both cleft subjects and non-cleft subjects with Class III malocclusion served as controls. Profile photos and CBCT scans for each patient were taken before (T0) and 18 months after the protraction (T1). 3D measurements were made on CBCT surface models from the treatment group using tomographic color mapping method. Cephalometric measurements were made on lateral cephalogram reconstructed from the CBCT scans and were compared with those obtained from the control groups. RESULTS: Two thirds of the treatment subjects showed improved lip projection towards more convex facial profile. The most significant skeletal changes on 3D surface models were observed at the zygomatic regions (mean 1.5-mm forward, downward, and outward displacement) and at the maxillary complex (mean 1.5-mm forward displacement). Compared with the control groups, the treatment subjects showed significant increase in the SNA and ANB angles, increased Wits appraisal, a more forward movement of point A and overjet improvement (p < 0.05). CONCLUSIONS: BAMP in cleft patients gives a significant forward displacement of the zygomaxillairy complex in favor of the Class III treatment. CLINICAL RELEVANCE: This treatment method shows clearly favorable outcome in cleft patients after 1.5 years of BAMP.