Comparative stability study of wire osteosynthesis versus rigid fixation in the treatment of Class III dentoskeletal deformities

Systematic mapping review of orthognathic surgery

STUDY DESIGN

Systematic mapping review AIM AND SCOPE: The objective of this mapping review was to identify, describe, and organize clinical research currently available from systematic reviews and primary studies regarding co-interventions and different surgical modalities used in orthognathic surgery (OS) and their outcomes.

METHODS

Systematic reviews (SRs), randomized controlled trials, and observational studies that evaluated perioperative OS co-interventions and surgical modalities were identified in an exhaustive search of MEDLINE, EMBASE, Epistemonikos, Lilacs, Web of Science, and CENTRAL. Grey literature was also screened.

RESULTS

Included were 35 SRs and 253 primary studies, 103 from SRs, and another 150 identified in our search. Overall, SR quality was rated as critically low, with only two SRs rated as of high quality. 19 questions on population, interventions, comparisons, and outcomes (PICO) extracted from the SRs focused on osteosynthesis methods, surgical cutting devices, and use of antibiotics, corticosteroids, and induced hypotension. Also identified were 15 research gaps. Evidence bubble maps were created to graphically depict the available evidence.

CONCLUSION

Future high-quality research, both primary and secondary, is needed to address the knowledge gaps identified in this systematic mapping review.

Evaluation of the postoperative stability of a counter-clockwise rotation technique for skeletal class II patients by using a novel three- dimensional position-posture method

The aim of this study is to evaluate the postsurgical stability of skeletal class II patients after performing a counter-clockwise rotational (CCWR) procedure for the maxilla-mandibular complex (MMC) by using a novel Three-dimensional (3D) Position-Posture(P-P) measuring method. Twenty-five patients (5 males and 20 females) were included in this study. The postoperative CT scans of the skull were taken before surgery(T0), 3-7 days (T1), 3 months (T2), and 6 months (T3) after surgery. Specific anatomic landmarks were chosen to determine the position of the segments, while three equally perpendicular planes were created to describe their posture. The results show that the linear relapse of maxillary landmarks during the follow-up were acceptable (≤0.5 mm). The relapse of maxillary pitch plane at 6-months follow-up is 1.52°, which is acceptable. There was a significant pitch plane relapse of the mandibular-body segment with an average of 1.86° between T1 and T2 models, 3.28° between T1 and T3 models. There was no significant difference between roll and yaw planes during the follow-up. We therefore conclude that the P-P method could be used to accurately analyze the postsurgical stability of skeletal class II orthognathic surgery cases. For CCWR procedures, it was also shown that the there is a tendency for recurrence most specially on the body of the mandible.

Assessment of the Postoperative Stability of Mandibular Orthognathic Surgery for Correction of Class III Skeletal Malocclusion

To assess the stability of mandible position after orthognathic surgery for correction of class III skeletal malocclusion. Twenty adult males, aged 18 to 40 years, with Angle class III skeletal malocclusion underwent preoperative orthodontic treatment for elimination of dental compensations followed by combined maxillomandibular surgery with rigid internal fixation. Lateral cephalograms from each patient, obtained in the natural head position before surgery, immediately after surgery, and at 6-month follow-up, were retrieved from the files of the Pontifical Catholic University of Rio Grande do Sul outpatient Oral and Maxillofacial Surgery clinic and compared. Comparison of craniometric landmark measurements showed that the precision of mandibular setback was compromised in the horizontal plane, with a mean mandibular relapse of 37.75% at point B and 45.85% at point Pg. Improved intercuspation and adaptation of the musculature to the new position of the jaws after orthognathic surgery lead to counterclockwise rotation of the mandible, ultimately displacing the mandible more anteriorly than desired.

Rapid palatal expansion. Part 2: Dentoskeletal changes in cats with patent versus synostosed midpalatal suture

Intercanine expansion (C-C) following rapid palatal expansion is made up of sutural displacement (Sd-Sd), tooth tip (Tt-Tt), tooth displacement (Td-Td), and alveolar process tipping and bending (At+b-At+b). The involvement of these four components was studied on 10 rapid palatal expansion treated and two control cats during an active phase (25 days), a retention phase (60 days), and a relapse phase (60 days). The midpalatal suture was analyzed for linear measurements, radiopaque versus radiolucent zones and optical density from occlusal radiographs. Nine treated cats exhibited sutural split and one treated cat showed no split as a result of synostosis of the suture. The contribution of the four constituents [(Sd-Sd):(Tt-Tt):(Td-Td):(At+b-At+b)] to the C-C expansion changed from active to relapse phase from [45%:15%:25%:15%] to [50%:25%:25%:0%] in the animals with sutural split and from [0%:40%:60%:0%] to [0%:0%:100%:0%] in the cat without sutural split, implying the major role of sutural displacement in patent suture, and tooth displacement in synostosed suture. The latter indicates the potential buccal corticalis fenestration, dehiscence or perforation in synostosed suture undergoing RPE. In patent suture (animals with sutural split), optical density increased during rapid palatal expansion (soft tissue build-up) and decreased during retention (remineralization) and relapse phases (medial convergence of the palatal processes). In the animal without sutural split, a continuous decrease in the optical density (predetermined ossification) was found. The progressive six-fold surge in coefficient of variation of C-C expansion during the relapse phase indicates limitation in predicting rapid palatal expansion stability. Clinically, the use of serial occlusal radiographs during rapid palatal expansion is recommended to evaluate patency and extent of retention period.