Trans oral approach to the nasopharynx and clivus using the Le Fort I osteotomy with midpalatal split

The Le Fort I level osteotomy is a procedure well known to oral and maxillofacial surgeons, who routinely use it to correct midfacial skeletal deformities and alter the dental occlusion. This osteotomy can also be used as a maxillotomy for access to more superiorly and posteriorly situated structures. The downfracture technique provides the surgeon with a safe approach that allows visualization of the maxillary sinuses, nasal cavity, nasopharynx, base of the skull and upper cervical spine. This approach can also be combined with a midline lip split, mandibulotomy and glossotomy to give access to retropharyngeal structures. By modifying the combined Le Fort I and transmandibular approach utilizing a midline split of the hard and soft palate, the access to the clivus can be improved considerably. The clinical applications of these combined procedures in the treatment of basilar invagination and tumors of the nasopharynx are discussed.     

Clinical outcomes of implants following lateral bone augmentation: systematic assessment of available options (barrier membranes, bone grafts, split osteotomy)

Objective: To compare the clinical outcomes related to implants following lateral augmentation procedures (GBR, bone grafts, split osteotomy) with implants placed in pristine sites.
Material and Methods: A systematic review of all prospective studies of implants placed simultaneously or as a second surgery following lateral augmentation compared with implants placed in pristine bone with 6 months of loading was performed.
Results: From 435 potentially relevant publications, 125 full-text publications were screened and four were identified as fulfilling the inclusion criteria. Three studies compared implants placed with simultaneous GBR or with a bone substitute and one with autogenous bone graft as a staged procedure. The implant survival at the augmented sites irrespective of the procedure used varied from 91.7% to 100% and from 93.2% to 100% at the control sites for a period between 12 and 59.1 months.
Conclusions: Within the limits of the systematic review there was evidence that the evaluated augmentation techniques result in similar implant survival between augmented and pristine sites. The small number of retrieved studies fulfilling the inclusion criteria limited the conclusions regarding the success of the augmentation and its effect on the survival of the implants. Properly designed randomized controlled clinical trials on this topic are needed.     

Comparison of stability of mandibular segments following the sagittal split ramus osteotomy with poly-l-lactic acid (PLLA) screws and titanium screws fixation

The purpose of this study was to retrospectively compare the stability of the mandible following the surgical orthodontic treatment by sagittal split ramus osteotomy (SSRO) and orthodontic multi-bracket treatment using fixation methods with poly-l-lactic acid (PLLA) or titanium screws. The sample examined was 23 subjects with PLLA screws (PLLA group) and 22 subjects with titanium screws (Titan group). Lateral cephalometric radiographs were reviewed before surgery (T0), 2–3 days after surgery (T1), 1 month after surgery (T2), and after postoperative orthodontic treatment (T3) and changes in the position of bony segments were examined by cephalometric linear and angular measurements. A similar movement of the mandible following setback surgery was indicated, and statistical analysis showed no significant differences in skeletal changes between the two groups during whole postoperative periods. However, a relapse following surgical counterclockwise rotation of the distal segment in PLLA group tended to be slightly greater during T1–T2 compared with Titan group. These results suggest that a use of the PLLA screw fixation may not influence on the stability of bony segments after mandibular setback surgery by SSRO during the postoperative period, although a slight tendency for clockwise rotation of the distal segment was indicated in patients with PLLA screws. It is suggested that fixation of bony segments with PLLA screws after SSRO may be effective in properly selected cases.     

不对称性下颌角肥大的手术治疗

目的　探讨不对称性下颌角肥大的原因及手术治疗。方法　采用下颌角弧形截骨术、下颌骨外板截骨术、颏成形术及颊脂垫取出术等方法,治疗不对称性下颌角肥大患者70例。结果　70例患者术后面部对称性均明显改善。70例患者中仅3例出现并发症,包括术后出血、口唇拉伤增生性瘢痕及术后感染等。结论　治疗不对称性下颌角肥大应根据畸形的特点,选择性应用下颌角弧形截骨术、下颌骨外板截骨术、颏成形术及颊脂垫取出术等方法,其效果良好。     

The influence of zero-value subtraction on the performance of two laser fluorescence devices for detecting occlusal caries in vitro

BACKGROUND: The aim of this study was to evaluate the influence of zero-value subtraction on the performance of two laser fluorescence (LF) devices developed to detect occlusal caries. METHODS: The authors selected 119 permanent molars. Two examiners assessed three areas (cuspal, middle and cervical) of both mesial and distal portions of the buccal surface and one occlusal site using an LF device and an LF pen. For each tooth, the authors subtracted the value measured in the cuspal, middle and cervical areas in the buccal surface from the value measured in the respective occlusal site. RESULTS: The authors observed differences among the readings for both devices in the cuspal, middle and cervical areas in the buccal surface as well as differences for both devices with and without the zero-value subtraction in the occlusal surface. When the authors did not perform the zero-value subtraction, they found statistically significant differences for sensitivity and accuracy for the LF device. When this was done with the LF pen, specificity increased and sensitivity decreased significantly. CONCLUSIONS: For the LF device, the zero-value subtraction decreased the sensitivity. For this reason, the authors concluded that clinicians can obtain measures with the LF device effectively without using zero-value subtraction. For the LF pen, however, the absence of the zero-value subtraction changed both the sensitivity and specificity, and so the authors concluded that clinicians should not eliminate this step from the procedure. CLINICAL IMPLICATIONS: When using the LF device, clinicians might not need to perform the zero-value subtraction; however, for the LF pen, clinicians should do so.     

Anterior mandibular apical base augmentation in the surgical orthodontic treatment of mandibular retrusion

The authors describe a surgical technique alternative to traditional pre-surgical orthodontics in order to increase the apical base in mandibular retrusion (class II, division I). This subapical osteotomy, optimizing inferior incisal axis without dental extractions and a long orthodontic treatment, associated to genioplasty permits to obtain an ideal labio-dento-mental morphology. This procedure avoids in some cases the need of a mandibular advancement and, if necessary, it reduces his entity with obvious advantages.     

Mandibular stability after sagittal split ramus osteotomy without post-operative maxillomandibular fixation in the treatment of prognathic patients with symmetric mandibles

This study was designed to examine post-operative stability in prognathic patients with symmetric lower jaws who underwent sagittal split ramus osteotomy (SSRO) of the mandible without post-operative maxillomandibular fixation (MMF). Twenty prognathic patients with symmetric mandibles were investigated. An appliance for repositioning the proximal segment and titanium screw fixation was applied in all patients. Ten patients underwent post-operative MMF with stainless steel wire (mean duration, 9.6 days) and intermaxillary rubber traction after removal of the MMF (Group I), and the remaining ten underwent intermaxillary rubber traction only (Group II) post-operatively. Cephalograms were obtained 2–3 days post-operatively, and 3, 6, and 12 months after surgery. Changes in the positions of upper incisors (U-1), lower incisors (L-1), B-point, and pogonion were examined on lateral cephalograms. In the early stages of follow-up, decreases in the overbite tended to be more marked in Group I than in Group II, and the forward movement of each standard point was significantly larger in Group I than in Group II. No significant differences, however, were revealed between the two groups at 12 months after surgery. Forward movement of anterior cephalometric landmarks, post-operatively, in Group II were significant, however, this pattern differed from Group I, in which big changes occurred in the early stages after surgery. Although the patterns of post-operative changes in the two groups are different, there are no significant differences in their post-operative stability in long-term follow-up. Therefore, post-operative MMF may be avoided when prognathic patients with symmetric mandibles undergo SSRO with an appliance for repositioning the proximal segment and titanium screw fixation.     

The stability of bilateral sagittal ramus osteotomy and vertical ramus osteotomy after bimaxillary correction of class III malocclusion

Introduction

The purpose of this retrospective cephalometric study was to compare the stability of bilateral sagittal split osteotomy (BSSO) with extra-oral vertical ramus osteotomy (VRO) after correction of class III malocclusion by means of bimaxillary orthognathic surgery.

Methods

The sample comprised 51 consecutively treated patients, 38 females and 13 males, with a mean age of 19.1 years. All had a one-piece Le Fort I osteotomy with maxillary advancement and mandibular setback. VRO was performed in 30 cases, and BSSO was performed in 21 cases. Lateral cephalograms were obtained before surgery, within 1 week of surgery and 1 year after surgery.

Results

The mean forward movement of the maxilla was 5.6 mm in both groups (p < 0.001). The mean horizontal surgical change in the VRO group was 4.4 mm (p < 0.001), and in the BSSO group it was 5.4 mm (p < 0.001). In the VRO group, the horizontal relapse was 1.2 mm (p < 0.001), and in the BSSO group, it was 1.4 mm (p < 0.001).

Conclusion

There was no difference in the stability between the BSSO and VRO groups. The average relapse in the whole sample was 26% of the surgical movement.     

超声骨切割技术的发展及其在口腔临床中的应用研究

骨切割是临床医学的一项基本技术，涉及与骨组织手术有关的临床学科，如口腔科、骨科、整形外科、神经外科和耳鼻咽喉科等。骨切割的效率和质量，直接影响到疾病的治疗效果。因此，临床上一直在探寻安全、高效的骨切割技术。骨切割技术的发展经历了传统的手动、气动和电动等切割方式，目前出现的超声骨切割技术将其带人了一个全新的时代。