A retrospective study of relapse in rigidly fixated sagittal split osteotomies: contributing factors

Fifty-one patients who underwent mandibular advancements with or without genioplasties were rigidly fixated with three, 2-mm bicortical screws per side. Radiographs were digitized preoperatively, immediately postoperatively, at 6 weeks, at 6 months, and at a subsequent long-term follow-up period. Location of the cephalometric landmarks, referenced to a vertical reference line (in millimeters), was used as the dependent variable. An overall inspection of the data shows that rigidly fixated mandibular advancements were very stable. The average case showed further advancement of pogonion from 6 weeks to the long-term follow-up period. However, relapse was noted in several cases. Factors that could be used as predictors of relapse were examined. Results indicated that magnitude of advancement was the only factor that successfully predicted relapse, accounting for 37.9% of the variance in the sample. Anatomic changes found to accompany such advancement are as follows: (1) when pogonion comes forward, anterior facial height and mandibular plane decrease while the proximal segment rotates forward, and (2) the maxillary central incisors flare and the mandibular incisors upright during this time period. A small degree of relapse as assessed at pogonion occurred during the first 6 weeks, followed by an advancement from 6 weeks to the longest time interval after the surgical procedure. However, these directional movements were not statistically significant.     

Longitudinal dento-skeletal changes in UCLP patients following maxillary distraction osteogenesis using RED system

Longitudinal dento-skeletal changes in unilateral cleft lip and palate (UCLP) patients following maxillary distraction osteogenesis using the rigid external distraction device (RED) were analyzed. Twelve Japanese non-syndromic UCLP patients who underwent maxillary distraction at the mean age of 16.4 years were used as subjects. Serial sets of lateral cephalograms, taken at 4 stages: 1) before osteotomy, 2) immediately after distraction, 3) 6 months and 4) 12 months post-osteotomy, were analyzed. Statistical analyses, including a paired t test, Pearson correlation analysis and stepwise linear regression analysis, were performed to distill characteristic dento-skeletal changes. In accordance with maxillary advancement, significant amounts of up-forward movement of the nasal bone, mandibular rotation and maxillary dental changes were observed. Maxillary dental changes were significantly related to the amount of mandibular rotation and force system of maxillary traction. Significant dento-skeletal relapse was found to occur during the 0-to-6-month follow-up period, but not in the 6-to-12-month follow-up period. Maxillary relapse was significantly related to the amount of maxillary advancement and severity of pre-surgical maxillary hypoplasia, while mandibular relapse was significantly related to maxillary dento-skeletal relapse. Successful clinical application of this procedure therefore requires consideration of both the surrounding dento-skeletal changes and the traction force system.     

Radiographic changes of the temporomandibular joint after oblique sliding osteotomy of the mandibular rami

64 patients with mandibular prognathism were operated upon with oblique sliding osteotomies of the mandibular rami. The patients were followed with cephalometric and temporomandibular joint (TMJ) radiographs for 3 years. 60% of the TMJs showed skeletal remodelling 3 years postoperatively. The condylar remodelling was significantly correlated to the degree of postoperative displacement of the condyle. The average condyle displacement postoperatively was about 3 mm inferiorly and anteriorly, but the position was almost completely back to normal during the control period, due to a combination of reverse movement of the condyle and remodelling. Mandibular relapse was not correlated to postoperative displacement of the condyle or condylar remodelling. The range of condylar movement was unchanged at follow-up.     

Bone resorption and complications in alveolar distraction osteogenesis

Distraction osteogenesis presents an alternative procedure for augmentation of atrophic alveolar bone prior to inserting dental implants. The aim of this retrospective study was to evaluate complications of this method with specific focus on bone resorption during the consolidation period and the follow-up period after dental implant insertion into distracted bone. Thirty partially edentulous patients underwent a total of 36 vertical alveolar distractions with an extraosseous distraction system. Eleven devices were placed in the maxilla and 25 in the mandible. Eighty-two dental implants were inserted after a mean consolidation period of 4.5 months. Treatment results were evaluated by means of panoramic radiographs for distraction follow-up and periapical radiographs for implant follow-up. The mean length of the transport segment was 19 mm. The average alveolar height achieved was 6.4 mm with a mean resorption of 1.8 mm (21.1%) at the time of dental implant insertion. Main problems comprised oral displacement of the transport segment (n = 15) and inadequate soft tissue extension (n = 13). Eighty-two dental implants were inserted with an overall survival rate of 95.1% after 45.8 months. For periimplant marginal bone, an average resorption of 3.5 mm was recorded 50.4 months after implant insertion. Although alveolar distraction osteogenesis seems to be an effective tool to treat vertical defects of the alveolar ridge, it is not an uncomplicated procedure. A combination with vestibular augmentation of autogenous bone grafts should be considered. Overcorrection of 20% may compensate bone relapse during the consolidation period of the distracted alveolar bone. Further bone resorption after dental implantation is common.     

Long-term changes of hyoid bone and pharyngeal airway size following advancement of the mandible

OBJECTIVE: To determine long-term changes in hyoid bone position and pharyngeal airway size after mandibular advancement, including evaluation of the relationship between length of suprahyoidal musculature and skeletal relapse. STUDY DESIGN: A cephalometric follow-up study (12 years) of 15 patients who underwent mandibular advancement surgery. RESULTS: The final position of the hyoid bone was more posterior than it had been preoperatively. Suprahyoidal musculature continuously lengthened from preoperatively to 12 years postoperatively. Total skeletal relapse at B-point and pogonion correlated significantly with postoperative stretch of suprahyoidal musculature. The upper and middle pharyngeal airways were narrower than their preoperative values. CONCLUSIONS: Mandibular changes influence hyoid bone position during the entire postoperative period, whereas stretching of suprahyoidal musculature seems to contribute to skeletal relapse. Mandibular advancement surgery alone possibly does not achieve a stable increase of pharyngeal airway size over a long-term period of 12 years.     

Postoperative stability for surgery-first approach using intraoral vertical ramus osteotomy: 12 month follow-up

The aim of this study was to evaluate the postoperative stability of the surgery-first approach using intraoral vertical ramus osteotomy (IVRO). We retrospectively studied a sample derived from the patients who were treated by the surgery-first approach using a LeFort I osteotomy and IVRO for correction of class III dentofacial deformity from 2008 to 2012. Lateral cephalograms taken preoperatively and 2 days, 6 months, and 12 months postoperatively were traced, and the skeletal and dental variables at different time points were analysed. The study sample comprised 37 subjects, mean (SD) age 23 (4) years. The mean (SD) total duration of treatment including postoperative orthodontics was 14 (6) months, and surgical movement of the maxillary A point was 0.75 (1.3) mm anteriorly, and 0.21 (1.79) mm superiorly. The surgical change in the position of the maxillary first molar was 1.01 (1.57) mm superiorly. The mean (SD) movement of mandible was 11.15 (5.4) mm posteriorly at pogonion and 1.02 (1.79) mm inferiorly at menton. There were no significant change in maxillary skeletal variables during the first year postoperative period. The surgical relapse of mandible at pogonion was 0.63 (2.31) mm anteriorly (p = 0.01), however, the relapse in superior direction at menton was 2.86 (1.39) mm with statistical significance (p = 0.01). The total duration of orthodontic treatment with surgery-first was roughly 5 months shorter than conventional preoperative and postoperative orthodontic treatment. The surgery-first approach using IVRO is effective and predictable, and shortens the overall duration of treatment. Anterior relapse of the mandible was less than 1 mm, and increased superior relapse can be compensated for with appropriate preoperative planning to provide a reliable outcome. This study was limited to 12 months’ follow-up, and a long term follow-up study is indicated.     

安氏Ⅱ类1分类拔牙病例正畸治疗后后牙关系的稳定性研究

目的　探讨安氏Ⅱ类1分类患者正畸治疗前、后后牙关系的变化趋势,分析可能影响后牙关系复发的因素。方法　选取采用拔牙治疗的安氏Ⅱ类1分类患者29例,其中男12例,女17例。根据ANB角进一步分为牙性Ⅱ类14例,骨性Ⅱ类15例。分别对其正畸治疗前、后进行模型测量和X线头影测量。结果　所有患者的Ⅱ类磨牙关系在治疗后均得到明显改善,随访时仅有少量复发。牙性Ⅱ类患者治疗后下磨牙近中移动量(4·52±2·15) mm,大于上磨牙移动量(3·62±2·62)mm,而骨性Ⅱ类患者上下磨牙近中移动量相似,但ANB角由治疗前的(6·27± 1·08)°明显减小为(4·64±1·17)°。随访时两类错患者上下颌磨牙均近中移动,且上颌磨牙移动量大于下颌磨牙。多元回归分析提示下颌骨水平向生长和上前牙不齐指数与磨牙关系复发有关。结论　Ⅱ类错患者正畸治疗后磨牙关系较为稳定。牙性Ⅱ类错磨牙关系的解除有赖于上下颌磨牙相对移动调整,骨性Ⅱ类错则依靠上下颌骨间位置关系的改变。有利的下颌生长型和上颌前牙不齐程度等与磨牙关系的保持有密切关系。     

Relapse following mandibular advancement with dental plus skeletal maxillomandibular fixation

This study examines the short-term stability of the mandible following mandibular advancement surgery in which skeletal suspension wires were used in addition to dental maxillomandibular fixation. Twenty adults underwent sagittal ramus osteotomies. No concomitant surgical procedures were performed. Maxillomandibular fixation consisted of wiring between the upper and lower orthodontic brackets and circummandibular wires connected to the piriform aperture or anterior nasal spine wires for eight weeks. Cephalograms were analyzed during this period to evaluate skeletal stability. A statistically insignificant mean horizontal relapse of 8.9% was found at pogonion during the period of fixation. Significant vertical intrusion of the anterior mandible occurred, however, with a mean superior movement of pogonion of 0.83 mm (P less than or equal to 0.05). Dental changes noted were uprighting of the maxillary incisors and flaring of the mandibular incisors. In comparison with the results of other studies in which dental maxillomandibular fixation was used alone, the results of this study indicate that the use of skeletal suspension wires is advantageous in the prevention of horizontal skeletal relapse.     

Condylar position following mandibular advancement: Its relationship to relapse

Forty-one patients who elected to receive a bilateral sagittal osteotomy to advance the mandible were examined clinically and radiographically to assess condylar position preoperatively and at three specific times post-operatively. Parameters designed to measure changes in condylar and distal fragment position were located on tracings and digitized for statistical analysis. Changes in distal fragment position included advancement and clockwise rotation during the surgical interval and significant posterior relapse with continued clockwide rotation during the period of maxillomandibular fixation. A small amount of counterclockwise rotation associated with interocclusal splint removal was seen following fixation release. No significant condylar movement was seen during the surgical interval. During the period of maxillomandibular fixation, both condyles exhibited a significant superior movement, and the left condyle also moved posteriorly. No changes in condylar position were noted following release of fixation. The clinical significance of these condylar movements is not clear. Despite minimal changes, 18 patients, six of whom had had no preoperative symptoms and one of whom had exhibited reciprocal clicking, complained of temporomandibular joint pain or noise postoperatively. This suggests that maintenance of condylar position during surgery may not prevent temporomandibular joint dysfunction. In addition, the observed 37% relapse in surgical advancement in the absence of significant condylar distraction implies the interaction of other factors in the relapse process.     

Surgically assisted rapid maxillary expansion in adults.

Twelve adults with maxillary width discrepancy of greater than 5 mm were treated by surgically assisted rapid maxillary expansion. The procedure consisted of bilateral zygomatic buttress and midpalatal osteotomies combined with the use of a tooth-borne orthopedic device postoperatively. Mean palatal expansion of 7.5 mm (range of 6 to 13 mm), measured in the first molar region, was achieved within 3 weeks in all patients. Expansion remained stable during the 12-month study period, with a mean relapse for the entire group of 0.88 +/- 0.48 mm. Morbidity was limited to mild postoperative discomfort. The results of this preliminary study indicated that surgically assisted rapid maxillary expansion is a safe, simple, and reliable procedure for achieving a permanent increase in skeletal maxillary width in adults. Further study is necessary to document the three-dimensional movements of the maxillary segments and long-term stability of the skeletal and dental changes.     

Relationship between dental care and oral health in institutionalized elderly people in Japan

This study examined the relationship between dental care and dental health status in institutionalized elderly people in Japan through a 6-year prospective cohort study. All the 719 subjects received both baseline and follow-up surveys. The uptake of dental care was examined at the follow-up survey. We examined the relationship between baseline variables and the provision of dental care, and the relationship between dental care and change of oral health status. About 47% of the subjects and about 60% of the baseline dentate subjects received some dental treatment during the 6-year follow-up period. The subjects who were in better systemic and dental health at baseline used dental services frequently. The number of teeth needing extraction decreased in the subjects who received dental treatment, and increased in the untreated subjects. Denture status was better in the treated subjects than in the untreated subjects. Dental care appears to be an important factor in maintaining a healthy oral status for the institutionalized elderly.     

Effects of Supervised Daily Dental Plaque Removal by Children: First-Year Results

In September 1973, a three-year school-based study was initiated in East Hampton, Connecticut, a rural nonfluoridated community. The purpose of the study is to determine the effect on dental decay, gingival inflammation and oral hygiene of removing dental plaque through supervised daily toothbrushing and flossing in school during a three-year period. To establish baseline data, three indexes were used: the DHC Index to evaluate gingivitis; the DMF Surface Index to quantify dental caries and the PHP Index to measure dental plaque. The examinations for dental caries, including radiographs, are scheduled annually in September, whereas the plaque and gingival examinations are done biannually, in September and June. After the baseline examinations the 481 children were blocked according to grade and sex and then were randomly assigned to either a treatment group or to a control group. In November, the treatment group was provided 10 sessions of instruction in plaque removal. For the remainder of the year (six months) they practiced daily plaque removal, supervised by a dental hygienist and a nurse. The control group was not instructed in oral hygiene procedures. In the treatment group, mean plaque and gingival scores at the June (first follow-up) examination were 14 percent and 29 percent lower, respectively, than at baseline. No change was seen in the control group. At the second follow-up examination in September (after summer vacation), the same indexes were nearly at baseline levels in the treatment group. There was no treatment effect on dental caries increments after one year of study. Considering the nature of the treatment regimen and the few treatments during the first year of the study, it is not surprising that there were no caries-preventive benefits demonstrated among children in the treatment group after one year. The total number of the plaque removal sessions will be greater during the second year of the study. Therefore, the possibility of detecting a caries preventive effect at the twenty-four month examinations, should one exist, will be enhanced.     

Dental and skeletal changes following sagittal split osteotomy for correction of mandibular prognathism

Skeletal and dental changes were examined in 15 patients presenting with a Class III malocclusion treated by a sagittal split osteotomy. All patients received orthodontic treatment with Straightwire appliances both prior to and following surgery. These appliances were also used for fixation. The lower incisors were proclined by 8.4 degrees before surgery with little change in upper incisor inclination. With surgery, there was a mean reduction of 4.3 degrees in the angle SNB. Following surgery, the relapse in mandibular position was minimal and was not related to the dental changes during this period. Changes in the vertical skeletal parameters were generally small. The individual cases exhibited a wide variation in the changes.     

Extraoral vertical ramus osteotomy combined with internal fixation for the treatment of mandibular deformities

Extraoral vertical ramus osteotomy (EVRO) is used in orthognathic surgery for the treatment of mandibular deformities. Originally, EVRO required postoperative intermaxillary fixation (IMF). EVRO has been developed using rigid fixation, omitting postoperative IMF. We examined retrospectively the long-term stability and postoperative complications for patients with mandibular deformities who underwent EVRO with internal rigid fixation. Patients who were treated with EVRO for a mandibular deformity in the period 2008–2017 at the Clinic of Oral and Maxillofacial Surgery, Mölndal, Sweden were included (N = 26). Overjet and overbite were calculated digitally and cephalometric analyses were performed preoperatively, and at three days, six months, and 18 months postoperatively. There was a general setback of the mandible, decreased gonial angle and reduced degree of skeletal opening. Excellent dental and vertical skeletal stabilities were seen up to 18 months postoperatively, although relapse was seen sagitally up to six months postoperatively. Since the overjet did not show any significant change over time, the sagittal skeletal changes have been attributed to dental compensation. There was no permanent damage to the facial nerve and 5.8% neurosensory damage to the inferior alveolar nerve was observed.     

Occlusal wear. A follow-up study of 18 subjects with extensively worn dentitions

Eighteen patients with moderate to severe dental wear were re-examined 6-10 years after a treatment period that included use of occlusal splints at night. The splints were used with various intensities for an average of 2 years. The methods of evaluation comprised a questionnaire, clinical examination, comparison of dental casts, salivary analysis, and bite force measurements. The changes in dental wear during the follow-up period were small, the typical finding being an increase of facets but no measurable reduction of tooth length. The results indicate that many variables apart from occlusal parafunctions, such as acid regurgitation and salivary and dietary factors, may contribute to loss of tooth substance diagnosed as dental wear. In most patients, the continuing wear process was slow after long-term treatment with occlusal splints.     

Stabilisation of sagittal split advancement osteotomies with miniplates: a prospective, multicentre study with two-year follow-up. Part I. Clinical parameters

The principal aim of this study was to assess the postoperative stability of bilateral sagittal split osteotomies (BSSO) using two miniplates. Part I reports on the clinical results including treatment characteristics, nerve functions, TMJ function, occlusional relapse and patient satisfaction. This prospective study evaluated a group of 222 patients who underwent a BSSO for mandibular advancement. The same treatment protocol was used at seven participating institutions at which the patients were treated. A stable occlusion without appreciable relapse was seen in 84% after 2 years of follow-up. A considerable minority (16%) had occlusal relapse. There were no clinical parameters that pointed towards a high risk for relapse except age. The mean operation age of the relapse group was 20.7 years (SD 6.7) and in the stable group 26.1 years (SD 8.2). The function of the inferior alveolar nerve 2 years postoperatively was reported to be normal in approximately 88% of the patients, while 94% had no complaints about nerve dysaesthesia. In approximately 56% of the patients with pre-existing TMJ-dysfunction these signs and symptoms had disappeared. Another group of patients, however, without TMJ-dysfunction preoperatively (22%) developed signs or symptoms of TMJ-dysfunction postoperatively. The sagittal split osteotomy fixed with miniplates appeared to be a relatively safe and reliable procedure giving rise to a high degree of patient satisfaction, despite the fact that some occlusal relapse was seen.     

Distraction osteogenesis in the management of mandibular hypoplasia secondary to temporomandibular joint ankylosis. Long term follow up

PurposeThe aim of this retrospective study was to evaluate the short-term and long-term skeletal and soft-tissue stability after MDO with or without genioplasty, as well as the stability of the achieved maximum inter-incisal opening (MIO) in patients with mandibular hypoplasia secondary to TMJ ankylosis.Patients and methodsTwenty patients with mandibular hypoplasia secondary to TMJ ankylosis were managed by a two-stage surgical protocol, gap arthroplasty as the first stage, followed by MDO. The patients were analyzed for skeletal and soft-tissue stability as well as the maintenance of the achieved MIO. Lateral cephalograms were evaluated at four time intervals: pre-distraction (T1), after a consolidation period with or without genioplasty (T2), after one year following consolidation (T3), and at the longest follow-up (T4). Statistical analyses compared the skeletal and soft-tissue changes at different intervals in every group.ResultsAll the ankylosed joints except three were treated with gap arthroplasty without costochondral graft. The MIO was increased from 8.2 ± 2.1 mm preoperatively to 40.2 ± 1.7 mm postoperatively. After the consolidation period, MIO decreased to 23 ± 6.5 mm. The patients were instructed to restart active physiotherapy after removal of the distractors to regain the pre-distraction MIO, which was maintained during the short-term follow-up. The mean follow-up period was 8.5 ± 1.5 years. At the end of the follow-up, two patients showed recurrence of ankylosis. Cephalometric analysis revealed great improvements in the hard- and soft-tissue structures after MDO with or without genioplasty. Several significant long-term relapses could be observed in all groups; however, they did not reach their pre-operative values.ConclusionTMJ ankylosis leads to severe, multidirectional mandibular hypoplasia, which is significantly corrected with the MDO. The MDO provides a stable short-term improvement in the facial esthetics at the first postoperative year, but a significant relapse occurs during the long term follow-up. Nevertheless, a satisfied facial esthetic is maintained for up to seven to 12 years postoperatively. During the activation period, the MDO minimizes the gained MIO after release of ankylosis, but the MIO is successfully restored with physiotherapy.     

Analysis of the development of the arch form after treatment using "ARCAD'Image" software

The dental arch post-therapeutic modification plays a significant role in relapse phenomenon. This article describes the design work of the dental arches used as a base for the study of modifications that have arisen during orthodontic treatment then during the retention stage using pre-formed arch wires. ARCAD'Image software tries to design the patients dental arches by submitting a linear regression mathematical design on some characteristic landmarks of a photograph of the buccal impression. The designed dental arch can then be considered as being the closest/nearest to the patients morphology. This model enables the practitioner to bend the arch wire and is used as a base for the study of arch shape modifications. Our study shows that the term "relapse" appears to be used excessively; it would be more matter of evolution due to changes in neuro-muscular balance along with facial aging.     

Trepanation and curettage treatment for acute implant periapical lesions

Six dental implants in six patients with periapical lesions were inserted and underwent trepanation and thorough curettage. During surgery, the lesion area was irrigated with copious natural saline and chlorhexidine and the bone defects were treated with tetracycline paste. The six implants were stable and asymptomatic postoperatively. The implants were loaded after 3 months. Radiologically, the radiolucency in the apical part disappeared gradually. These prostheses have functioned satisfactorily with no further complication during the follow-up period. For cases in which small lesions initially appear soon after implant placement, trepanation and curettage of the periapical lesion without resection of the apical part of the implant or bone substitute material and/or autogenous bone grafting is an effective management option. A rapid and exact diagnosis is important for treating implant periapical lesions.     

三维测量法分析上颌骨垂直向发育不足患者正颌术后稳定性

目的: 采用三维重建方法评价上颌骨垂直向发育不足患者正颌术后上颌骨位置变化,以探讨该类患者术后颌骨的稳定性及其影响因素。方法: 选取2016 年1月—2016年9月上海交通大学医学院附属第九人民医院口腔颅颌面科应用Le Fort I型截骨术矫治上颌骨垂直向发育不足的患者50例,收集术前2个月（T0）、术后3 d（T1）、术后6个月（T2）的三维CT图像,分别利用Proplan CMF 3.0软件对前鼻嵴点（ANS）、腭大孔点（GPL/R）进行测量,采用SPSS 13.0软件包对上述测量值进行样本均数t检验,比较该类患者术后上颌骨的稳定性;并对具有明显复发倾向者进行回归分析以及工作特征曲线分析,以探索其影响因素。结果: 统计学分析发现,ANS-FH（T2-T1）出现显著变化,平均上移1.11 mm（P<0.05）。术后垂直向复发现象主要与上颌骨术中的垂直向移动距离以及上颌骨后部的术中垂直向移动有关。结论: 应用Le Fort I 型截骨术矫治上颌骨垂直向发育不足患者具有一定复发倾向,其稳定性受到上颌骨术中位移距离及术后随访时间的影响。