Influencing factors for the development of obstructive sleep apnea after orthognathic surgery in skeletal class III patients: A systematic review

This systematic review aimed to investigate the factors that may contribute to the development of OSA after orthognathic surgery in patients with skeletal class III. Electronic searches of PubMed, Embase, Web of Science, and Cochrane databases were conducted up to December 10, 2022. In total, 277 studies were retrieved and screened according to the inclusion and exclusion criteria, and 14 were finally selected. All studies were of medium quality (moderate risk of bias). The occurrence of OSA after orthognathic surgery in patients with class III skeletal relationships depends on surgical factors and patient self-factors. Surgical factors include surgery type, amount of maxillary and mandibular movement, and the patient's postoperative swelling. Patient self-factors include weight, age, gender, and hypertrophy of the soft palate, tonsils, and tongue. According to information in the 14 selected articles, the incidences of OSA after Le Fort I impaction and BSSO setback, BSSO setback, and Le Fort I advancement and BSSO setback were 19.2%, 8.57%, and 0.7%, respectively, mostly accompanied with greater amounts of mandibular recession. However, no clear evidence exists to confirm that orthognathic surgery is a causative factor for postoperative sleep breathing disorders in patients with mandibular prognathism. The wider upper airway in patients with class III skeletal might be the reason for the rare occurrence of OSA after surgery. In addition, obesity and advanced age may lead to sleep apnea after orthognathic surgery. Obese patients should be advised to lose weight preoperatively.

Tongue Reduction Surgery Improves Mandibular Prognathism in Beckwith-Wiedemann Syndrome Without Compromising Tongue Function

OBJECTIVES

This study evaluated the surgical outcomes of patients with Beckwith-Wiedemann syndrome who underwent tongue-reduction surgery and analyzed whether the malocclusion and mandibular prognathism caused by macroglossia could be improved.

METHODS

A retrospective medical record review was performed for 11 patients with Beckwith-Wiedemann syndrome whose macroglossia was surgically treated. Demographic data, symptoms and signs, and intraoperative and postoperative surgical outcomes were evaluated. Surgery was performed by a single surgeon using the "keyhole" technique, involving midline elliptical excision and anterior wedge resection. Preoperative and postoperative plain skull lateral X-rays were evaluated to assess prognathism improvement.

RESULTS

The median age at the time of surgery was 35.09 months, and the ratio of males to females was 4:7. The median surgical time was 98±31.45 minutes, and the median duration of the postoperative intensive care unit stay was 3.81±2.4 days. There were no airway complications. Two patients (18.2%) had postoperative wound dehiscence; however, there was no nerve damage, recurrence, or other complications. Among the five patients who underwent postoperative speech evaluation, all showed normal speech development, except one patient who had brain dysfunction and developmental delay. Measurements of the A point-nasion-B point (ANB) angles and sella-nasion-B point (SNB) angles (point A is the most concave point of the anterior maxilla; point B is the most concave point on the mandibular symphysis) on plain X-rays showed a significant decrease in the postoperative SNB angle (P <0.001) and a significant increase in the ANB angle (P <0.011).

CONCLUSION

Tongue-reduction surgery is an effective and safe technique for severe forms of macroglossia associated with Beckwith-Wiedemann syndrome. In addition, it improves mandibular prognathism in young Beckwith-Wiedemann syndrome patients with macroglossia.

Radiographic Findings of Congenital Facial Infiltrating Lipomatosis: A Case Report

Congenital diffuse infiltrating lipomatosis of the face (CDIL-F) is a rare clinicopathological entity with an unknown etiology, in which mature adipose tissue infiltrates the soft tissue structures in one side, and causes considerable asymmetry. Herein, we report a case of CDIL-F who underwent many surgical procedures without definite diagnosis during 12 years. CDIL-F presents symptoms with various severity levels due to infiltration of adipose tissue that makes removal difficult. Thus, it is recommended to inform patients about the high rate of recurrence.

Skeletal stability after bimaxillary surgery with surgery-first approach for class III asymmetry is not related to virtual surgical occlusal contact

OBJECTIVES

Surgery-first orthognathic surgery is rarely used in class III asymmetry due to concerns of reduced skeletal stability from unstable surgical occlusion. This study aimed to evaluate if skeletal stability after surgery-first orthognathic surgery is related to virtual surgical occlusal contact or surgical change.

MATERIALS AND METHODS

We studied 58 adults with class III asymmetry, consecutively corrected by Le Fort I osteotomy and bilateral sagittal split osteotomy using a surgery-first approach. Dental casts were manually set to measure virtual surgical occlusal contact including contact distribution, contact number, and contact area. Cone-beam computed tomography taken before treatment, 1-week post-surgery, and after treatment was used to measure surgical change and post-surgical stability of the maxilla and mandible in translation (left/right, posterior/anterior, superior/inferior) and rotation (pitch, roll, yaw). The relationship between skeletal stability and surgical occlusal contact or surgical change was evaluated with correlation analysis.

RESULTS

Significant instability was found in the mandible but not in the maxilla. No correlation was found between the maxillary or mandibular stability and surgical occlusal contact (all p > 0.01). However, a significant correlation was found between the maxillary (roll and yaw) or mandibular (shift, roll and pitch) stability and its surgical change (all p < 0.001).

CONCLUSIONS

In correction of class III asymmetry with surgery-first bimaxillary surgery, the skeletal stability is not related to the virtual surgical occlusal contact, but surgical skeletal change.

CLINICAL RELEVANCE

Planned over-correction is a reasonable option for correction of severe shift or roll mandibular asymmetry in bimaxillary surgery for class III deformity.

The role of the dentist and orthodontist in recognizing oro-facial manifestations of acromegaly: a questionnaire-based study

PURPOSE

Oro-facial manifestations of acromegaly are among the earliest signs of the disease and are reported by a significant number of patients at diagnosis. Despite this high prevalence of acromegaly oral manifestation, dentists do not play a pivotal role in acromegaly identification and diagnosis. The aim of our study was to evaluate the ability of dentists and orthodontists in the early recognition of the oro-facial manifestations of acromegaly.

METHODS

A telematic questionnaire was administered to dentists and orthodontists. The questionnaire included photos with facial and oral-dental details and lateral teleradiography of acromegaly patients (ACRO).

RESULTS

The study included 426 participants: 220 dentists and 206 orthodontists. Upon reviewing the photos, dentists most often observed mandibular prognathism and lips projection, while orthodontists also reported the impairment of relative soft tissue. Orthodontists, who usually use photos to document patients' oral-facial characteristics, paid more attention to oral-facial impairment than dentists. During dental assessment, 90% of the participants usually evaluated tongue size and appearance, diastemas presence, and signs of sleep impairment (mainly orthodontists). Orthodontists were also more able to identify sella turcica enlargement at teleradiography. A total of 10.8% of the participants had ACRO as patients and 11.3% referred at least one patient for acromegaly suspicion.

CONCLUSION

The study highlighted dentists' strategic role in identifying ACRO. Increasing dentists' awareness about acromegaly clinical issues may improve early diagnosis, potentially resulting in an increased quality of life and decreased mortality among ACRO.

Skeletal maturation and the location of the mandibular foramen within the ramus mandibulae

PURPOSE

It is well documented that the mandible does not grow at a constant rate. There are significant correlations between the increase of mandibular size and cervical vertebral maturation. The peak growth velocity of the mandible occurs after the third stage of cervical vertebral maturation. The location of the mandibular foramen (MF) and its changes subsequent to growth are of great interest to clinicians as they relate to the anesthesia of the inferior alveolar nerve and to mandibular surgical procedures. Therefore, the aim of the present study was to assess the influence of the mandibular growth spurt on the location of the MF in various skeletal growth patterns.

METHODS

Panoramic and lateral cephalometric radiographs of 98 (32 orthognathic, 50 retrognathic, 16 prognathic) patients before and after the growth peak were collected. For each subject, the maturational stage of the cervical vertebrae was defined on successive lateral cephalograms and the vertical and horizontal position of the MF was evaluated on two panoramic radiographs, one before and one after the growth peak.

RESULTS

The MF-Post/MF-Ant ratio (MF distance to the posterior border of the ramus/MF distance to the anterior border of the ramus) significantly increased after the growth peak in orthognathic and retrognathic subjects (P = 0.015 and 0.02, respectively). This ratio did not significantly increase in prognathic subjects (P = 0.882). No statistically significant changes in the vertical position of the MF were found in the three groups after the growth spurt.

CONCLUSION

The horizontal position of the MF moves in an anterior direction in orthognathic and retrognathic subjects during the mandibular growth spurt. The vertical position of the mandibular foramen remains unchanged during this period.

Sagittal split ramus osteotomy, intraoral vertical ramus osteotomy, and lateral corticectomy for asymmetric mandibular prognathism

Objectives

The purpose of this study was to evaluate the postoperative anteroposterior stability and improvements in facial asymmetry after performing LeFort I osteotomy in the maxilla, sagittal split ramus osteotomy (SSRO) and intraoral vertical ramus osteotomy (IVRO) in the mandible, and lateral corticectomy on the IVRO side.

Materials and Methods

From July 2009 to October 2018, a retrospective analysis was performed on 11 subjects. Lateral cephalometric radiograph was performed preoperatively (T0), postoperatively (T1), and at 12 months of follow-up (T2), and the B point distance was measured. Posteroanterior cephalometric radiograph was performed preoperatively (S0) and at 12 months of follow-up (S1) and was used to measure five indicators (Ag angle, M-Ag, Co-Ag, Co-Me, and Ag-Me) of facial asymmetry.

Results

The B point distances for T0 and T1 were significantly different (P=0.007), whereas those for T1 and T2 were not significantly different (P=0.1). In addition, there was a significant difference between the B point distances of T2 and T0 (P=0.026). Comparison of the facial asymmetry indicators before and after surgery showed a significant difference for all indicators between S0 and S1 the P-values of Ag angle, M-Ag, Co-Ag, Co-Me, and Ag-Me were 0.003, 0.003, 0.008, 0.006, and 0.004, respectively. The Z value was based on negative ranks.

Conclusion

There was no significant difference in the B point distances from postoperation to the 12-month follow-up. However, there were significant differences in all five indicators related to facial asymmetry before and after surgery. The values for the five indicators of facial asymmetry all increased postoperatively.

Comparative assessment of osteotomy cut using bur and saw for bilateral sagittal split osteotomy of mandible: a prospective clinical study

PURPOSE

To compare the intraoperative utility of bur and saw and to examine the pattern of lingual split during bilateral sagittal split osteotomy of mandible.

MATERIAL AND METHODS

This study prospectively compares the intraoperative utility of bur and saw in bilateral sagittal split osteotomy as split-mouth model. Study includes 16 patients (representing 32 sagittal split osteotomies) divided into two groups. The procedure to be performed was explained to the patient, followed by written informed consent. The institutional ethical committee approved the clinical study and all subjects gave informed consent.

RESULTS

We found that the ease of handling of the bur was good compared to saw. The duration required for completion of osteotomy using bur was less compared to saw.

CONCLUSIONS

The use of surgical drills and burs is still the gold standard in most developing nations and countries in transition like India. Depending upon the expertise of the surgeon, availability of precise dissecting instruments, one can go with either of the instrument for BSSO.

Orthognathic surgery in a precocious edentulous patient

This paper aims to discuss orthognathic surgery in a precocious edentulous patient as a viable alternative treatment. The present article is a case report of a total edentulous patient 32 years ago, with a double denture and dentofacial deformity, aggravated due to the early loss of teeth. Orthognathic surgery is a procedure that has been gaining more and more space in the specialty of maxillofacial surgery and traumatology because it is currently more accessible to patients due to the reduction in surgery costs and the greater number of surgeons who perform it, among others. The vast majority of patients who undergo this surgery are young adults. However, age does not impede orthognathic performance, older patients prefer other types of treatment due to its morbidity. Orthognathic surgery is a viable and highly predictable treatment in cases of prosthetic rehabilitation of totally edentulous patients.

Why most patients do not exhibit obstructive sleep apnea after mandibular setback surgery?

Maxillomandibular advancement (MMA) is effective for the treatment of obstructive sleep apnea (OSA). In previous studies, the airway was increased in the anteroposterior and transverse dimensions after MMA. However, the effect of the opposite of mandibular movement (mandibular setback) on the airway is still controversial. Mandibular setback surgery has been suggested to be one of the risk factors in the development of sleep apnea. Previous studies have found that mandibular setback surgery could reduce the total airway volume and posterior airway space significantly in both the one-jaw and two-jaw surgery groups. However, a direct cause-and-effect relationship between the mandibular setback and development of sleep apnea has not been clearly established. Moreover, there are only a few reported cases of postoperative OSA development after mandibular setback surgery.

These findings may be attributed to a fundamental difference in demographic variables such as age, sex, and body mass index (BMI) between patients with mandibular prognathism and patients with OSA. Another possibility is that the site of obstruction or pattern of obstruction may be different between the awake and sleep status in patients with OSA and mandibular prognathism. In a case-controlled study, information including the BMI and other presurgical conditions potentially related to OSA should be considered when evaluating the airway. In conclusion, the preoperative evaluation and management of co-morbid conditions would be essential for the prevention of OSA after mandibular setback surgery despite its low incidence.

Acoustic Analysis of Voice and Speech in Men with Skeletal Class III Malocclusion: A Pilot Study

OBJECTIVES

To assess the fundamental (f0) and first third formant (F1, F2, F3) frequencies of the 7 oral vowels of Brazilian Portuguese in men with skeletal class III malocclusion and to compare these measures with a control group of individuals with Angle's class I.

METHODS

Sixty men aged 18-40 years, 20 with Angle's class III skeletal malocclusion and 40 with Angle's class I malocclusion were selected by speech therapists and dentists. The speech signals were obtained from sustained vowels, and the values of f0 and frequencies of F1, F2 and F3 were estimated. The differences were verified through Student's t test, and the effect size calculation was performed.

RESULTS

In the class III group, more acute f0 values were observed in all vowels, higher values of F1 in the vowels [a] and [ε] and in F2 in the vowels [a], [e] and [i] and lower F1 and F3 values of the vowel [u].

CONCLUSION

More acute f0 values were found in all vowels investigated in the class III group, which showed a higher laryngeal position in the production of these sounds. The frequencies of the first 3 formants showed punctual differences, with higher values of F1 in the vowels [a] and [ε] and of F2 in [a], [e] and [i], and lower values of F1 and F3 in the vowel [u] in the experimental group. Thus, it is concluded that the fundamental frequency of the voice was the main parameter that differentiated the studied group from the control.

Volumetric characteristics of prognathic mandible revealed by skeletal unit analysis

The purpose of this study was to evaluate the skeletal units of a normal mandible (class I) and a prognathic mandible (class III), to compare the groups, and to investigate the key functional unit responsible for mandibular prognathism. Hemi-mandibles of 101 cases were evaluated by cone-beam computed tomography. Of these, 50 cases had Class I and 51 had Class III mandibles. The length, volume, and volume/length ratio of each skeletal unit were measured. The ratios of the condyle, body unit, and sum of the hemi-mandible between Class I and Class III showed statistically significant results (P<0.05). However, the ratios of angle, coronoid, and symphysis units did not show any statistical significance on comparison. Dependent on gender, in males the ratio of the condyle of the hemi-mandible showed statistically significant results (P<0.05). Meanwhile in females the ratio of the body and sum of the hemi-mandible showed statistically significant results (P<0.05). Accordingly, the mandibular body and condylar units are thinner in mandibular prognathism. On the basis of the functional matrix theory to determine the aetiology of mandibular prognathism, the key skeletal units are the body and condylar units.

Octreotide use for rescue of vision in a pregnant patient with acromegaly

Pregnancy in acromegaly is rare and generally safe, but tumour expansion may occur. Managing tumour expansion during pregnancy is complex, due to the potential complications of surgery and side effects of anti-tumoural medication. A 32-year-old woman was diagnosed with acromegaly at 11-week gestation. She had a large macroadenoma invading the suprasellar cistern. She developed bitemporal hemianopia at 20-week gestation. She declined surgery and was commenced on 100 µg subcutaneous octreotide tds, with normalisation of her visual fields after 2 weeks of therapy. She had a further deterioration in her visual fields at 24-week gestation, which responded to an increase in subcutaneous octreotide to 150 µg tds. Her vision remained stable for the remainder of the pregnancy. She was diagnosed with gestational diabetes at 14/40 and was commenced on basal bolus insulin regimen at 22/40 gestation. She otherwise had no obstetric complications. Foetal growth continued along the 50th centile throughout pregnancy. She underwent an elective caesarean section at 34/40, foetal weight was 3.2 kg at birth with an APGAR score of 9. The neonate was examined by an experienced neonatologist and there were no congenital abnormalities identified. She opted not to breastfeed and she is menstruating regularly post-partum. She was commenced on octreotide LAR 40 mg and referred for surgery. At last follow-up, 2 years post-partum, the infant has been developing normally. In conclusion, our case describes a first presentation of acromegaly in pregnancy and rescue of visual field loss with somatostatin analogue therapy. Learning points: Tumour expansion may occur in acromegaly during pregnancy. Treatment options for tumour expansion in pregnancy include both medical and surgical options. Somatostatin analogues may be a viable medical alternative to surgery in patients with tumour expansion during pregnancy.

Oro-dental pathologies in acromegaly

PURPOSE

Oro-dental pathologies (ODP) such as enlargement of the tongue, mandibular prognathism, and spaced teeth are characteristic features of acromegaly. Their frequency of occurrence during the course of the disease is largely unresolved. Purpose of this study was to assess ODP and oro-dental treatments in patients with acromegaly with regard to the length of the diagnostic process, tumor histology, and quality of life (QoL).

METHODS

Single-center retrospective survey study using questionnaires on dental symptoms, diagnostic process, and treatment in patients with acromegaly operated on a growth hormone-secreting pituitary adenoma. The association between ODP and QoL was assessed using the Short-Form 36 (SF-36) Health Survey.

RESULTS

145/314 patients completed the questionnaires. 80.7% were affected by any ODP, most frequently enlargement of the tongue (57.9%), spaced teeth (42.8%), mandibular growth (24.1%), and mandibular prognathism (22.1%). ODP were significantly more frequent in patients with sparsely vs. densely granulated adenomas (p = 0.045). Early diagnosis within 2 years was associated with significantly fewer ODP than later diagnosis (68.5 vs. 87.2%, p = 0.009). Treatments included dental crowns (16.6%), dental bridges (12.4%), dental implants (9.7%), dental prostheses (3.4%), orthodontal (i.e., braces, 6.9%), and surgical correction of the teeth (2.1%). Physical QoL was significantly lower in patients with ODP than in those without (p = 0.014).

CONCLUSION

In our large series of patients, four of five patients were affected by ODP at any time during the course of the disease. The results highlight the importance of early identification and treatment of oro-dental problems in patients with acromegaly as hallmarks of the disease.

Comparative study of postoperative stability between conventional orthognathic surgery and a surgery-first orthognathic approach after bilateral sagittal split ramus osteotomy for skeletal class III correction

Objectives

The purpose of this study is to compare the postoperative stability of conventional orthognathic surgery to a surgery-first orthognathic approach after bilateral sagittal split ramus osteotomy (BSSRO).

Materials and Methods

The study included 20 patients who underwent BSSRO for skeletal class III conventional orthognathic surgery and 20 patients who underwent a surgery-first orthognathic approach. Serial lateral cephalograms were analyzed to identify skeletal changes before surgery (T0), immediately after surgery (T1), and after surgery (T2, after 1 year or at debonding).

Results

The amount of relapse of the mandible in the conventional orthognathic surgery group from T1 to T2 was 2.23±0.92 mm (P<0.01) forward movement and −0.87±0.57 mm (non-significant, NS) upward movement on the basis of point B and 2.54±1.37 mm (P<0.01) forward movement and −1.18±0.79 mm (NS) upward movement on the basis of the pogonion (Pog) point. The relapse amount of the mandible in the surgery-first orthognathic approach group from T1 to T2 was 3.49±1.71 mm (P<0.01) forward movement and −1.78±0.81 mm (P<0.01) upward movement on the basis of the point B and 4.11±1.93 mm (P<0.01) forward movement and −2.40±0.98 mm (P<0.01) upward movement on the basis of the Pog.

Conclusion

The greater horizontal and vertical relapse may appear because of counter-clockwise rotation of the mandible in surgery-first orthognathic approach. Therefore, careful planning and skeletal stability should be considered in orthognathic surgery.

Hard and Soft Tissue Changes Following Maxillary Distraction Osteogenesis and Mandibular Setback with Bilateral Sagittal Split Osteotomy

AIMS OF THIS STUDY

(1) To highlight the role of intraoral submerged device in distraction osteogenesis (DO) of patients requiring two jaw surgeries for the correction of severe developmental maxillary hypoplasia (MH) and mandibular prognathism (MP) (2) To analyse the hard and soft tissue changes following maxillary DO and mandibular setback with bilateral sagittal split osteotomy (BSSO) in patients with severe MH and MP requiring two jaw surgeries.

MATERIALS AND METHODS

During the period Jan 2004 to Dec 2006, five patients with severe developmental MH along with MP were treated. In 1st stage maxillary distraction was done. Distraction started on 6th postoperative day, 1 mm distraction was carried out for 10-15 days on either side. Serial radiographs were taken immediate postoperative period for baseline comparison, post-distraction and at the end of distraction. After a period of 3-4 months of distraction 2nd stage was done. In 2nd stage, mandibular setback was done with BSSO and distractors were removed under general anesthesia. Radiographs were taken immediately and at 4 months post-operatively. Cephalometric tracings were carried out preoperatively, post DO and finally after mandibular setback with BSSO.

RESULTS

The mean horizontal movement of maxilla was 11.4 mm at ANS and 9.6 mm at A point. Upper incisor edge was advanced by 8.8 mms. SNA increased by 8.4° and SNB decreased by 4.6°. Nasal projection advanced by 4°. Nasolabial angle normalized in all patients, mean change achieved was 10.8°. Upper lip moved forward by 5.4 mm. Lower lip moved backward by 5.4 mm. Mandible positioned backward by 4 mm at B point. No vertical change occurred in the position of A, ANS and upper incisor edges. Mean increase in skeletal angle of convexity was 26.4°. Concave profile was significantly changed to convex in all patients.

CONCLUSION

Maxillary DO and mandibular setback with BSSO was associated with improved facial balance and esthetics.

Effects of airway evaluation parameters on the laryngeal view grade in mandibular prognathism and retrognathism patients

BACKGROUND

Failure to maintain a patent airway can result in brain damage or death. In patients with mandibular prognathism or retrognathism, intubation is generally thought to be difficult. We determined the degree of difficulty of airway management in patients with mandibular deformity using anatomic criteria to define and grade difficulty of endotracheal intubation with direct laryngoscopy.

METHODS

Measurements were performed on 133 patients with prognathism and 33 with retrognathism scheduled for corrective esthetic surgery. A case study was performed on 89 patients with a normal mandible as the control group. In all patients, mouth opening distance (MOD), mandibular depth (MD), mandibular length (ML), mouth opening angle (MOA), neck extension angle (EXT), neck flexion angle (FLX), thyromental distance (TMD), inter-notch distance (IND), thyromental area (TMA), Mallampati grade, and Cormack and Lehane grade were measured.

RESULTS

Cormack and Lehane grade I was observed in 84.2%, grade II in 15.0%, and grade III in 0.8% of mandibular prognathism cases; among retrognathism cases, 45.4% were grade I, 27.3% grade II, and 27.3% grade III; among controls, 65.2% were grade I, 26.9% were grade II, and 7.9% were grade III. MOD, MOA, ML, TMD, and TMA were greater in the prognathism group than in the control and retrognathism groups (P < 0.05). The measurements of ML were shorter in retrognathism than in the control and prognathism groups (P < 0.05).

CONCLUSIONS

Laryngoscopic intubation was easier in patients with prognathism than in those with normal mandibles. However, in retrognathism, the laryngeal view grade was poor and the ML was an important factor.

Sleep-disordered breathing following mandibular setback: a systematic review of the literature

INTRODUCTION

A mandibular setback reduces space in the pharyngeal airway, and it has been suggested that it might induce sleep-disordered breathing.

OBJECTIVES

An evidence-based literature review was conducted to identify the effect of mandibular setback on the respiratory function during sleep.

METHODS

The authors performed a systematic review of pertinent literature published up to 2014. A structured search of literature was performed, with predefined criteria. A survey of the PubMed, ScienceDirect, and Cochrane database was performed. A manual search of oral and maxillofacial surgery-related journals was accomplished. Potentially relevant studies then had their full-text publication reviewed.

RESULTS

A total of 1,780 publications were evaluated, through which nine papers (seven case series and two case-control studies) were selected for the final review. No evidence of sleep disorder after six months was related in 223 patients. In one study, two patients developed obstructive sleep apnea syndrome after surgery, and in another two studies, seven patients presented an increase of obstructive apneas/hypopneas events and oxygen desaturation index. Most of the patients analyzed were young and thin.

CONCLUSION

There was no evidence of postoperative sleep apnea syndrome after a mandibular setback surgery. However, one should always consider a potential reduction of the upper airway space during the treatment plan. Obese patients and those submitted to large amounts of mandibular setbacks present a higher chance to develop obstructive sleep apnea syndrome.

Combined surgical-orthodontic rehabilitation of cleidocranial dysplasia: 5 years follow-up

Cleidocranial dysplasia (CD) is an autosomal dominant syndrome which is characterized by several skeletal malformations such as non-closed fontanelles, skeletal abnormalities of the maxilla and mandible and absence of clavicles. Mid-facial hypoplasia and mandibular prognathism are mostly seen jaw abnormalities in CD. In this study, the combined orthodontic-surgical treatment of a patient with CD with class III malocclusion and multiple unerupted primary and deciduous teeth is presented.

Tumor-suppressor Genes, Cell Cycle Regulatory Checkpoints, and the Skin

The cell cycle (or cell-division cycle) is a series of events that take place in a cell, leading to its division and duplication. Cell division requires cell cycle checkpoints (CPs) that are used by the cell to both monitor and regulate the progress of the cell cycle. Tumor-suppressor genes (TSGs) or antioncogenes are genes that protect the cell from a single event or multiple events leading to cancer. When these genes mutate, the cell can progress to a cancerous state. We aimed to perform a narrative review, based on evaluation of the manuscripts published in MEDLINE-indexed journals using the Medical Subject Headings (MeSH) terms “tumor suppressor's genes,” “skin,” and “cell cycle regulatory checkpoints.” We aimed to review the current concepts regarding TSGs, CPs, and their association with selected cutaneous diseases. It is important to take into account that in some cell cycle disorders, multiple genetic abnormalities may occur simultaneously. These abnormalities may include intrachromosomal insertions, unbalanced division products, recombinations, reciprocal deletions, and/or duplication of the inserted segments or genes; thus, these presentations usually involve several genes. Due to their complexity, these disorders require specialized expertise for proper diagnosis, counseling, personal and family support, and genetic studies. Alterations in the TSGs or CP regulators may occur in many benign skin proliferative disorders, neoplastic processes, and genodermatoses.

Changes of the Airway Space and the Position of Hyoid Bone after Mandibular Set Back Surgery Using Bilateral Sagittal Split Ramus Osteotomy Technique

Purpose:

Although there have been several studies of reduced airway space after mandibular setback surgery using the sagittal split ramus osteotomy technique, research on the risk factors for changes of the airway space is lacking. Therefore, this study was performed to examine airway changes and the position of the hyoid bone after orthognathic surgery, and to assess possible risk factors.

Methods:

In this retrospective study, 50 patients who underwent posterior displacement of the mandible by the bilateral sagittal split ramus osteotomy technique were included. Changes of the position of the hyoid bone and the airway space were analyzed over various follow-up periods, using cephalometric radiography taken preoperatively, immediately after surgery, eight weeks after surgery, six months after surgery, and one year after surgery. To identify risk factors, multiple regression analysis of age, gender, body mass index (BMI), posterior mandibular movement, and the presence of genioplasty was performed.

Results:

Inferor and posterior movement of the hyoid bone was observed postoperatively, but subsequent observations showed regression towards the anterosuperior aspect. The airway space also significantly decreased after surgery (P <0.05), and increased slightly up until six months after surgery. The airway space significantly decreased (β=0.47, P <0.01) as the amount of mandibular setback increased. However, age, sex, BMI, and presence of genioplasty were not associated with airway reduction.

Conclusion:

The amount of mandibular set back was significantly associated with postoperative reduction of airway space. It is necessary to establish a treatment plan considering this factor.

Three-dimensional evaluation of lingual split line after bilateral sagittal split osteotomy in asymmetric prognathism

OBJECTIVES

The aim of this study was to evaluate the pattern of lingual split line when performing a bilateral sagittal split osteotomy (BSSO) for asymmetric prognathism. This was accomplished with the use of cone-beam computed tomography (CBCT) and three-dimensional (3D) software program.

MATERIALS AND METHODS

The study group was comprised of 40 patients (20 males and 20 females) with asymmetric prognathism, who underwent BSSO (80 splits; n=80) from January 2012 through June 2013. We observed the pattern of lingual split line using CBCT data and image analysis program. The deviated side was compared to the contralateral side in each patient. To analyze the contributing factors to the split pattern, we observed the position of the lateral cortical bone cut end and measured the thickness of the ramus that surrounds the mandibular lingula.

RESULTS

The lingual split patterns were classified into. The true "Hunsuck" line was 60.00% (n=48), and the bad split was 7.50% (n=6). Ramal thickness surrounding the lingual was 5.55±1.07 mm (deviated) and 5.66±1.34 mm (contralateral) (P=0.409). The position of the lateral cortical bone cut end was classified into three types: A, lingual; B, inferior; C, buccal. Type A comprised 66.25% (n=53), Type B comprised 22.50% (n=18), and Type C comprised 11.25% (n=9).

CONCLUSION

In asymmetric prognathism patients, there were no differences in the ramal thickness between the deviated side and the contralateral side. Furthermore, no differences were found in the lingual split pattern. The lingual split pattern correlated with the position of the lateral cortical bone cut end. In addition, the 3D-CT reformation was a useful tool for evaluating the surgical results of BSSO of the mandible.

Application of spherical coordinate system to facial asymmetry analysis in mandibular prognathism patients

Purpose

The purpose of this study was to compare asymmetric mandibular prognathism individuals with symmetric mandibular prognathism individuals using a new alternate spherical coordinate system.

Materials and Methods

This study consisted of 47 computed tomographic images of patients with mandibular prognathism. The patients were classified into symmetric and asymmetric groups. Mandibular and ramal lines were analyzed using an alternate spherical coordinate system. The length as well as midsagittal and coronal inclination angle of the lines was obtained. The bilateral differences of the spherical coordinates of the facial lines were statistically analyzed in the groups.

Results

There were significant differences between the groups in bilateral difference of the length and midsagittal inclination angle of the lines (p<0.05). The bilateral difference of the length and midsagittal inclination angle of the lines has significant correlation with chin deviation (p<0.05).

Conclusion

The new alternate spherical coordinate system was able to effectively evaluate facial lines. The bilateral difference of lengths and midsagittal inclination of the facial lines might contribute to the facial asymmetry in mandibular prognathism individuals.