[A long-term 3D cast model analysis focusing bone-borne vs. tooth-borne SARME].

UNLABELLED: This retrospective study evaluated 34 patients pre- and ~20.5 months post expansion 3D scanned cast models with tooth-borne (ТВ, n1=16) and bone-borne (BB, n2=18) devices. Measurements were performed for transverse skeletal/dental maxillary widening, dental tipping and dental attachment loss. RESULTS: T-Test in long-term effects: BB: bigger, symmetric transverse widening along the dental arch; bigger attachment loss in the frontal teeth, canines, 2nd premolars. molars; bigger dental tipping in the canines and 2nd molars; ТВ: asymmetric transverse widening along the dental arch; bigger attachment loss in the 1st premolars: bigger dental tipping in the premolars and 1st molars. CONCLUSION: BB should be used whenever bigger transverse maxillary expansion is required, new distractor designs may reduce segmental inclination and initial expansion asymmetries, consequently, eliminating the related attachment loss from secondary orthodontic tooth movements for arch alignment. ТВ devices showed minor expansion with good periodontal attachment, yet attachment loss in the first premolars must be critically seen in bigger expansion distances.

Fixation of mandibular fractures with plates or miniplates: prospective study.

AIM: The choice of a more adequate internal fixation system in the treatment of mandibular fractures still originates controversy in the literature. The purpose of this study was to evaluate the effectiveness of internal fixation systems in the fixation of mandibular fractures, comparing indications and postoperative results between 2.4-mm plates and 2.0-mm miniplates. METHODS: A total of 42 consecutive patients with 71 mandibular fractures that had undergone either 2.4-mm plates (N.=20) or 2.0-mm miniplates (N.=22) were prospectively analyzed. Patients had a minimum follow-up of 6 months. Statistical analyses were made in the comparison between systems. RESULTS: There was no significant difference in the choice of systems as to age and characteristics of the fractures, but in patients with systemic diseases or chronic substance abuse, as well as in exposed fractures, with more frequency of 2.4-mm plates. 2.0-mm miniplates presented better recovery of jaw opening in the postoperative period. Temporary facial nerve deficit was observed exclusively in the case of extraoral approach. Both systems presented low rate of complications which required reoperation, however 2.0-mm miniplates presented better efficacy when compared to 2.4-mm plates. CONCLUSION: In conclusion, 2.0-mm miniplates should be always used when possible in the fixation of mandibular fractures, respecting their contraindications.

Palatal piezosurgical window osteotomy for maxillary sinus augmentation.

This technical note describes a new surgical technique for a palatal approach to the maxillary sinus for a vertical augmentation prior to dental implant placement. In 12 fully or partially edentulous patients (seven women, five men), 16 palatal sinus elevations were performed. After elevation of palatal full-thickness flap a rectangular access window was cut with a piezosurgical device. The raised sinus cavity was augmented with a synthetic nano-structured hydroxyapatite-based graft material. No harm occurred to the greater palatine artery or the sinus membrane. The vestibular and periimplant gingiva were preserved and there was no disharmonious soft tissue distortion or massive scar formation. Swelling and bleeding were minimal. Primary stability was achieved for all but one implant. This technique may be an alternative to other sinus augmentation approaches in cases where enough transversal width of the posterior alveolar crest is available.

Computation of a tetrahedral mesh for striated muscle deformation simulation.

Competing concepts exist regarding surgery for instance of the cleft lip and palate to date. Morphology-based simulations at histological scale may one day be used to help the surgeon predict the possible outcome of a variety of approaches. It however can be a challenge to generate volume meshes that are applicable to the mathematical modelling of three-dimensional spatial modifications. Computation of surface meshes may be considered less delicate. The aim of this study is to design and evaluate a novel algorithm that supports finite element methods. Images of histological serial sections of a striated muscle were segmented. Results of the three-dimensional reconstruction of multiple layers of the polygonal segmentation data characterized the hull of the muscle. The corresponding surface mesh was then converted into a tetrahedral mesh to generate volume. This was achieved by mapping multiple template types onto neighbouring intersection polygons. Muscle contraction was subsequently simulated by mesh deformation. The technique successfully generated volumes and was able to provide data on contraction directions. The mesh supported a novel approach to simulate representations of contraction. However, several drawbacks were evident. Mathematical modelling of scenarios with more than one striated muscle will require considerable modification of the currently presented approach. Future studies need to then evaluate the applicability of volume meshes to represent arrays of three-dimensional biological objects. Surface mesh based mathematical modelling of cleft lip and palate surgery and its results are therefore not yet in reach.

Complex facial trauma with combined surgical and orthodontic rehabilitation.

Severe panfacial trauma require broad reconstructive procedures. As in the case presented, a primary reconstruction with ideal aesthetic outcome cannot be reached in every case. If not, these cases often require further reconstructive procedures. What this can be and how long this could take, this article intends to show. This case report presents the history of a today 30 year old male patient with a severe central midfacial comminuted fracture with preexisting Angle class II and comprehensive reconstruction.

[Virtual tissue. Quaoaring]. / Virtuelles Gewebe. Quaoaring.

Virtual tissue can be generated by employing various methods. First steps en route to virtual tissue may encompass the generation of virtual cells. One such approach termed Quaoaring was applied to produce artificial erythrocytes and these were both discocyte and echinocyte in shape. The results were subsequently compared with data gleaned from scanning electron microscopy and atomic force microscopy. Quaoaring has, however, proved to be unsuccessful in creating convincing objects, particularly those which should be echinocytic in appearance.

[Analysis of histological datasets by signal processing methods]. / Signaltheoretische Analyse histologischer Daten im Ortsfrequenzraum.

In the present study, a semi-automatic segmentation and classification algorithm is proposed for the analysis of histological and cytological images. In view of the fact that histological and cytological images usually exhibit poor contrast and blurred outlines, classical segmentation algorithms often fail to detect relevant structures. A new algorithm for texture segmentation based on signal processing methods in combination with machine learning techniques was therefore developed.

Piezoosteotomy in orthognathic surgery versus conventional saw and chisel osteotomy.

INTRODUCTION: Piezoosteotomy was assessed as alternative osteotomy method in orthognathic surgery regarding handling, time requirement, nerve and vessel impairment. MATERIALS AND METHODS: In this comparative clinical experience, 90 patient's orthognathic surgery procedures were performed in typical distribution prospectively by piezoosteotomy: 34 (38%) monosegment, 47 (52%) segmented LeFortI osteotomies, 94 (52%) sagittal split osteotomies, 11 (12%) symphyseal, and 4 (2%) mandibular body osteotomies. As controls served 90 retrospective patients with conventional saw and chisel osteotomy: 58 (64%) monosegment, 27 (30%) segmented LeFortI osteotomies, 130 (72%) sagittal split, and 4 (4%) symphyseal osteotomies. RESULTS AND DISCUSSION: Piezoosteotomies were individually designed to interdigitate the jaw segments after repositioning. The pterygomaxillary suture weakened angulated tools; auxiliary chisels were required in 100% of cases for the nasal septum and lateral nasal walls, in 33% for pterygoid processes. The dorsal maxilla as the pterygoid process were easily reduced; 15% mandibular osteotomies required sawing, while the lingual dorsal osteotomy was performed by manual feedback due to limited visibility. Bloodloss decreased from average 537 +/- 208 ml vs. 772 +/- 338 ml (p = 0.0001). Operation time remained unchanged: 223 +/- 70 min vs. 238 +/- 60 min (p = 0.2) for a conventional bimaxillary procedure. Clinical courses and reossification were unobtrusive. Alveolar inferior nerve sensitivity was retained in 98% of the piezoosteotomy collective versus 84% of controls (p = 0.0001) at 3 months postoperative testing. CONCLUSION: Piezoelectric osteotomy did not prolong the operation and reduced blood loss as alveolar nerve impairment. A few patients required additional sawing or chisel. Piezoelectric screw insertion as complex osteotomies may be initiated to simplify the procedure and increase segment interdigitation after repositioning as to minimize the osteofixation time and dimensions.

Prospective evaluation of a pragmatic treatment rationale: open reduction and internal fixation of displaced and dislocated condyle and condylar head fractures and closed reduction of non-displaced, non-dislocated fractures Part II: high condylar and condylar head fractures.

This study prospectively evaluated closed reduction (CR) outcomes in non-displaced, non-dislocated high-condylar and condylar-head fractures (Class VI after Spiessl and Schroll) and open reduction and internal fixation (ORIF) of displaced (Class III) or dislocated (Class V) fractures. Thirty-eight patients with 54 fractures (16 (42%) with bilateral fractures, 14 (37%) CR, 24 (63%) ORIF) were enrolled in a 1 year follow-up that 18 patients with 33 fractures completed. Condylar translation in Class VI fractures recovered to 11 mm for vertical opening, 8mm for protrusion and 10 mm for mediotrusion; Class III synonymously 8 mm, 8 mm and 6 mm; and Class V 7 mm, 6mm and 7 mm; incisal movements recovered to 38 mm, 8 mm and 8 mm in Class VI; 55 mm, 7 mm and 10 mm in Class III with 1 (8%) malocclusion, 1 (8%) impaired vertical opening and 55 mm, 7 mm and 9 mm in Class V with 2 (18%) malocclusions. Fragment-reduction versus the non-fractured condyle was -0.3 mm to +1.3 mm and +3 degrees to +9 degrees in Class VI, -1 mm to -0.2 mm and +3 degrees to +2 degrees in Class III, -3.3 mm to +3.1 mm and -11.2 degrees to +1 degrees in Class V. Malocclusion and joint locking were unreliable determinants for a treatment decision, being forged by concomitant fractures. Joint movements were within normal range at 1-year follow-up except Classes III and V vertical opening translation. After predefined criteria, 92% successful outcomes were attained. Multiple factor analysis should be used to prospectively evaluate the unacceptable clinical outcomes. Class VI fractures with intact vertical support should prospectively be evaluated whether these benefit from ORIF.

In-patient versus in vitro degradation of P(L/DL)LA and PLGA.

To assess and compare degradation rates, poly(70L-lactide-co-30DL-lactide) [P(L/DL)LA] and poly(85L-lactide-co-15-glycolide) (PLGA) copolymer degradation were studied in patients (maxillofacial region) and in vitro. Five patients of a total of 20 with 85:15 PLGA osteosyntheses, and 15 of a total of 60 with 70:30 P(L/DL)LA osteosyntheses, (10 females and 10 males, 26-55 years; mean, 33 years) underwent explantations after 3, 6, 9, 12, 18, and 24 months. Identical resorbables immersed in physiological buffer solution at 37 degrees C were compared at identical intervals. P(L/DL)LA's initial average molecular weight of 45,000 decreased to 25,000 in patients (and to 21,000 in vitro) after 6 months, and to 8000 in patients after 18 months. PLGA's average molecular weight decreased from 44,600 to 22,000 after 3 months in patients and in vitro, and to 11,000 in patients and 1300 in vitro at 6 months. In-patient and in vitro glass-transition temperatures decreased from approximately 60 degrees C to 50 degrees C over 18 months. Crystallinity in explants was < or = 4% in P(L/DL)LA throughout testing, and 16% and 30% in PLGA at 6 and 12 months, respectively. Both copolymers decomposed reliably in patients: 85:15 PLGA within 12 months and 70:30 P(L/DL)LA within 24 months on average (p < 0.005), leaving only extremely small granules that powder upon finger touch. In vitro rates were significantly faster (p < 0.005). Crystallinity associated with foreign-body reactions was minor and did not inhibit decomposition.

Prospective evaluation of a pragmatic treatment rationale: open reduction and internal fixation of displaced and dislocated condyle and condylar head fractures and closed reduction of non-displaced, non-dislocated fractures. Part I: condyle and subcondylar fractures.

This prospective study evaluated outcomes of closed reduction (CR) in non-displaced, non-dislocated condyle and subcondylar fractures (Class I) and open reduction and internal fixation (ORIF) of displaced (Class II) and dislocated (Class IV) fractures. Forty-five patients with 51 fractures (six (13%) with bilateral fractures), 11 (25%) CR and 34 (75%) ORIF, were enrolled in a 1-year follow up that 20 patients with 25 fractures completed. Condylar translation in Class I fractures recovered to 12mm for vertical opening, 9mm for protrusion, 8mm for mediotrusion; in Class II, respectively, 10, 7 and 9mm; and Class IV, respectively, 8, 7 and 7mm. Incisal movements recovered to 46, 8 and 9mm in Class I; 44, 7 and 9mm in Class II; and 43, 5 and 7mm in Class IV. Vertical and angular fragment reduction versus the non-fractured condyle was +0.3 to -1.9mm, +1.1 degrees to +1.8 degrees in Class I; -2.2 to -1.9mm, +0.6 degrees to -1.2 degrees in Class II; +2.9 to -1.1mm, +18.4 degrees to +6 degrees in Class IV. Malocclusion and joint locking were unreliable determinants for a treatment decision, being forged by concomitant fractures. All complications subsided after 6 months; translation and incisal movements returned to within the normal range in proportion to the severity of displacement and dislocation. Vertical opening translation in Class IV fractures remained short-to-normal and was compensated by rotation. Unacceptable clinical function according to predefined standards was not found after 1 year. Angular reposition was better than vertical reduction. This study documents successful evidence-based treatment according to predefined criteria.