Mandibular repositioning in adult patients - an alternative to surgery?: A two-year follow-up

Abstract Background Adult patients presenting with skeletal discrepancies may refuse surgical intervention. Materials and methods Thirty-two patients who declined orthognathic correction of their maxillo-mandibular dysplasia and who were without signs of temporomandibular dysfunction (TMD) were offered mandibular repositioning as a non-invasive alternative. Simulating a skeletal correction, it was explained that the approach was based on results described in case reports. Before commencing treatment, initial records, lateral and frontal head films, study casts and photos were obtained (T0) and the mandible was repositioned to camouflage a retrognathic skeletal discrepancy or a mandibular transverse asymmetry by means of an occlusal build-up using Triad™ gel. Results Three months later (T1), 23 patients had adapted to the new occlusion reflected by an absence of functional disturbance and without fracture of the composite occlusal build-up. Mandibular position in these patients was maintained by additional orthodontic treatment and an adjustment of the occlusion to the built-up postured position (T1). The skeletal changes occurring during repositioning were assessed on sagittal and frontal head films while intra-articular changes occurring during a two-year follow-up period (T2) were evaluated on images constructed from CBCT scans. No significant change, either in the direction of relapse or in the direction of further normalisation of condylar position, were observed during the two-year observation period. Conclusion Mandibular repositioning is a non-invasive intervention that may be considered a valid alternative to surgery in selected patients. Morphological variables from the radiographs taken at T0 and the results of the initial clinical evaluation of dysfunction yielded only vague and insignificant indicators regarding the predictability of the adaptation. A CBCT scan at T0 might have contributed to the identification of the patients who would likely accept the repositioning

3D evaluation of mandibular skeletal changes in juvenile arthritis patients treated with a distraction splint: A retrospective follow-up

Objective:  To evaluate three-dimensional (3D) condylar and mandibular growth in patients with juvenile idiopathic arthritis (JIA) with unilateral temporomandibular joint involvement treated with a distraction splint. Materials and Methods:  Cone-beam computed tomography (CBCT) scans were taken for 16 patients with JIA with unilateral TMJ involvement before treatment (T0) and 2 years after treatment (T1). All patients received orthopedic treatment with a distraction splint. Eleven patients without JIA who were undergoing orthodontic treatment without a functional appliance or Class II mechanics and who had taken CBCT scans before and after treatment, served as controls. Reconstructed 3D models of the mandibles at T0 and T1 were superimposed on stable structures. Intra- and intergroup growth differences in condylar and mandibular ramus modifications and growth vector direction of the mandibular ramus were evaluated. Results:  In all patients with JIA there were asymmetric condylar volume, distal and vertical condylar displacement, and ramus length differences that were smaller on the affected side. Condylar displacement was more distal and less vertical in the JIA group than in the control group. A larger distal growth of the condylar head and a more medial rotation of the ramus on the affected side were found in the JIA group. Conclusion:  The orthopedic functional treatment for patients with JIA allows for condylar adaptation and modeling, thereby hindering, although with a widely variable response, a further worsening of the asymmetry. Unilateral affection has a possible influence on the growth of the nonaffected sideS

Three-Dimensional Morphological Changes of the True Cleft under Passive Presurgical Orthopaedics in Unilateral Cleft Lip and Palate: A Retrospective Cohort Study

The aim of this cohort study was to quantify the morphological changes in the palatal cleft and true cleft areas with passive plate therapy using a new analysis method based on three-dimensional standardized reproducible landmarks. Forty-five casts of 15 consecutive patients with complete unilateral cleft lip and palate were laser scanned and investigated retrospectively. The landmarks and the coordinate system were defined, and the interrater and intrarater measurement errors were within 1.0 mm. The morphological changes of the cleft palate area after a period of 8 months of passive plate therapy without prior lip surgery are presented graphically. The median decrease in cleft width was 38.0% for the palatal cleft, whereas it was 44.5% for the true cleft. The width of the true and palatal cleft decreased significantly over a period of 8 months. The true cleft area decreased by 34.7% from a median of 185.4 mm2 (interquartile range, IQR = 151.5âEuro"220.1) to 121.1 mm2 (IQR = 100.2âEuro"144.6). The palatal cleft area decreased by 31.5% from a median of 334 mm2 (IQR = 294.9âEuro"349.8) to 228.8 mm2. The most important clinical considerations are the reproducibility and reliability of the anatomical points, as well as the associated morphological changes. We propose using the vomer edge to establish a validated measuring method for the width, area, and height of the true cleft

Quantification of temporomandibular joint space in patients with juvenile idiopathic arthritis assessed by cone beam computerized tomography

Objective To describe a method to calculate the total intra-articular volume (inter-osseous space) of the temporomandibular joint (TMJ) determined by cone-beam computed tomography (CBCT). This could be used as a marker of tissue proliferation and different degrees of soft tissue hyperplasia in juvenile idiopathic arthritis (JIA) patients. Materials and Methods Axial single-slice CBCT images of cross-sections of the TMJs of 11 JIA patients and 11 controls were employed. From the top of the glenoid fossa, in the caudal direction, an average of 26 slices were defined in each joint (N = 44). The interosseous space was manually delimited from each slice by using dedicated software that includes a graphic interface. TMJ volumes were calculated by adding the areas measured in each slice. Two volumes were defined: Ve−i and Vi, where Ve−i is the inter-osseous space, volume defined by the borders of the fossa and Vi is the internal volume defined by the condyle. An intra-articular volume filling index (IF) was defined as Ve−i/Vi, which represents the filling of the space. Results The measured space of the intra-articular volume, corresponding to the intra-articular soft tissue and synovial fluid, was more than twice as large in the JIA group as in the control group. Conclusion The presented method, based on CBCT, is feasible for assessing inter-osseus joint volume of the TMJ and delimits a threshold of intra-articular changes related to intra-articular soft tissue proliferation, based on differences in volumes. Intra-articular soft tissue is found to be enlarged in JIA patientsS

Stressors and resources mediate the association of socioeconomic position with health behaviours

Peer reviewedPublisher PD

The Effect of Symmetric and Asymmetric Loading of Frontal Segment with Two Curved Cantilevers: An In Vitro Study

Cantilevers generate statically determined force systems. The frontal segment loading with symmetric and asymmetric cantilevers in a three-piece intrusion base arch can be used to correct midline asymmetry. Three types of 0.017″ × 0.025″ beta-titanium cantilevers: tip-back (TB), deep curve (DC), utility arch (UA) were tested on typodonts simulating intrusion of the maxillary anterior segment. Typodonts with symmetric and asymmetric cantilevers were scanned with intraoral scanner (3Shape, TRIOS, Copenhagen, Denmark) before (T0) and after (T1) the experiment, scans were superimposed using Mimics software (Materialise, Leuven, Belgium). Data were analysed with qualitative analysis. All cantilevers generated vertical and horizontal forces. For symmetric design, the DC and TB displayed intrusive force with retrusive component, UA intrusion and protrusion. The asymmetric cantilevers produced transverse displacement of anterior segment. DC created lateral, UA medial force, the anterior segment displacement was consistent with the used configuration. The movement of an anterior segment with TB is smaller compared to DC and UA. Symmetric cantilevers configurations can achieve simultaneous intrusion and retrusion or protrusion of the anterior segment. The asymmetric design with transversal force can clinically aid the correction of midline discrepancies. The effect of the cantilever configuration on delivered force direction was confirmed

Load Transfer during Magnetic Mucoperiosteal Distraction in Newborns with Complete Unilateral and Bilateral Orofacial Clefts: A Three-Dimensional Finite Element Analysis

The primary correction of congenital complete unilateral cleft lip and palate (UCLP) and bilateral cleft lip and palate (BCLP) is challenging due to inherent lack of palatal tissue and small extent of the palatal shelves at birth. The tissue deficiency affects the nasal mucosa, maxillary bone and palatal mucosa. This condition has driven the evolution of several surgical and non-surgical techniques for mitigating the inherent problem of anatomical deficits. These techniques share the common principle of altering the neighboring tissues around the defect area in order to form a functional seal between the oral and nasal cavity. However, there is currently no option for rectifying the tissue deficiency itself. Investigations have repeatedly shown that despite the structural tissue deficiency of the cleft, craniofacial growth proceeds normal if the clefts remain untreated, but the cleft remains wide. Conversely, craniofacial growth is reduced after surgical repair and the related alteration of the tissues. Therefore, numerous attempts have been made to change the surgical technique and timing so as to reduce the effects of surgical repairs on craniofacial growth, but they have been only minimally effective so far. We have determined whether the intrinsic structural soft and hard tissue deficiency can be ameliorated before surgical repair using the principles of periosteal distraction by means of magnetic traction. Two three-dimensional maxillary finite element models, with cleft patterns of UCLP and BCLP, respectively, were created from computed tomography slice data using dedicated image analysis software. A virtual dental magnet was positioned on either side of the cleft at the mucoperiosteal borders, and an incremental magnetic attraction force of up to 5 N was applied to simulate periosteal distraction. The stresses and strains in the periosteal tissue induced by the magnet were calculated using finite element analysis. For a 1 N attraction force the maximum strains did not exceed 1500 µstrain suggesting that adaptive remodeling will not take place for attraction forces lower than 1 N. At 5 N the regions subject to remodeling differed between the UCLP and BCLP models. Stresses and strains at the periosteum of the palatal shelf ridges in the absence of compressive forces at the alveolar borders were greater in the UCLP model than the BCLP model. The findings suggest that in newborns with UCLP and BCLP, periosteal distraction by means of a magnetic 5 N attraction force can promote the generation of soft and hard tissues along the cleft edges and rectify the tissue deficiency associated with the malformation

Force Systems Produced by Different Cantilever Configurations during Deactivation

Intrusion with a three-piece arch is routinely achieved during orthodontic treatment. This study aimed to experimentally determine how the cantilever design influences the generated force system. Both straight and arch-formed cantilever designs: tip-back (TB), flat curve (FC) deep curve (DC), and 3 mm and 6 mm high utility arch (UA3; UA6) were activated for 5 mm and 10 mm. Force systems were determined by a hexapod. Typodonts simulating a three piece-intrusion arch were scanned using an intraoral scanner (3Shape, TRIOS, Denmark) before (T0) and after (T1) the experiment and superimposed with Mimics software (Materialise, Leuven, Belgium). Data were analyzed. All straight designs displayed an extrusive force in the vertical plane, and all arch-formed an intrusive force. DC and TB showed a retrusive force in the sagittal plane and UA6 a protrusive. For the medial/lateral forces, DC and TB displayed a medial, and UA6 a lateral force. Configurations can be distinctively ranked from DC, FC, TB to UA3, and UA6 according to the increasing protrusive nature of the generated sagittal forces. A DC or TB configuration should be used for intrusion and retraction, while for an intrusion and a protrusion, a UA6 configuration. All straight configurations showed a higher force level than the arch-formed configurations