Residents' journal review

Predictability of pharyngeal airway space dimension changes after orthognathic surgery in class II patients: A mathematical approach

Magnetic resonance imaging assessment of posterior airway space (PAS) after maxillomandibular advancement in patients with obstructive sleep apnea

Few investigations have evaluated the 3-dimensional (3D) accuracy of digital implant scans. The aim of this study was to evaluate the performance of 10 intraoral scanners (IOSs) (CEREC Omnicam, CEREC Primescan, CS 3600, DWIO, i500, iTero Element, PlanScan, Trios 2, Trios 3, and True Definition) in obtaining the accurate positions of 6 cylinders simulating implant scan bodies. Digital scans of each IOS were compared with the reference dataset obtained by means of a coordinate measuring machine. Deviation from the actual positions of the 6 cylinders along the XYZ axes and the overall 3D deviation of the digital scan were calculated. The type of IOSs and position of simulated cylindrical scan bodies affected the magnitude and direction of deviations on trueness. The lowest amount of deviation was found at the cylinder next to the reference origin, while the highest deviation was evident at the contralateral side for all IOSs (p < 0.001). Among the tested IOSs, the CEREC Primescan and Trios 3 had the highest trueness followed by i500, Trios 2, and iTero Element, albeit not statistically significant (p > 0.05), and the DWIO and PlasScan had the lowest trueness in partially edentulous mandible digital implant scans (p < 0.001).

Continuous positive airway pressure (CPAP) intolerance remains a persistent problem for many obstructive sleep apnea patients. Clinicians and researchers continue to search for other effective treatment modalities given the well-documented sequelae associated with untreated obstructive sleep apnea. A multidisciplinary "Alternatives to CPAP program" (ALT) can facilitate systematic evaluation of non-CPAP therapies appropriate for an individual patient. We review successful strategies and barriers encountered during implementation of an ALT at our institution. Creation of similar programs in private practice and academic settings can help medical, dental, and surgical sleep medicine specialists coordinate evaluation and treatment of CPAP-intolerant patients.

Background and Objectives: Obstructive sleep apnea (OSA) is a sleep-related breathing disorder, characterized by disrupted snoring and repetitive upper airway obstructions. Continuous positive airway pressure (CPAP) is considered the therapeutic mainstay for OSA patients. However, CPAP therapy has compliance limitations. An alternative treatment options is maxillomandibular advancement (MMA) surgical procedure. Genial tubercle advancement (GTA) is often performed concomitant with MMA for esthetic purposes. Cone-beam computed tomography (CBCT) provides the ability to visualize the upper airway and perform three-dimensional (3D) reconstructions. The purpose of this study is to evaluate the impact of MMA procedure with or without GTA on oropharyngeal airway space in OSA patients and the stability after completion of orthodontic treatment. Methods: A total of 25 patients (18 females and 7 males) with a mean age of 37.1 ± 17.3 years were included in the study. CBCT scans were taken before treatment (T1); after pre-surgical orthodontic treatment (T2); immediately after MMA procedure (T3); and at 10 months follow-up visit (T4). Thus, (T2-T1) represented changes due to orthodontic treatment only; (T3–T2) represented changes due to MMA procedure; and (T4-T3) represented changes due to follow-up after surgery. Each patient served as his/her own control. Fifteen of the individuals underwent MMA with GTA. All DICOM files were analyzed using Dolphin 3D Imaging software program to determine total airway volume (TAV), airway area (AA) and minimum axial area (MAA) at explicit regions along the posterior airway space. Dolphin 3D voxel-based superimposition was used to determine the amount of skeletal advancement with MMA and changes after surgery. Results: Significant increase in TAV, AA and MAA was found with MMA treatment (40.61%; 28.77%; and 56.40%, respectively, p Conclusions: Significant increase in OPAS can be expected with MMA surgery with or without GTA procedure in patients diagnosed with OSA. Significant forward movement of the maxilla, mandible and chin positions can be obtained with MMA procedure. A partial loss in OPAS was found during the 10 months follow-up period. The surgical movements were found to be stable with less than 1 mm of relapse during the follow-up period, which was not clinically significant.

Teenage sleep-disordered breathing: Recurrence of syndrome

A comparison of postoperative, three-dimensional soft tissue changes in patients with skeletal class III malocclusions treated via orthodontics-first and surgery-first approaches

To evaluate the relationship between soft tissue and bone structure for Class III patients before and after bilateral sagittal split osteotomy (BSSO) and bimaxillary orthognathic surgery; to determine the impact of other factors on soft tissue change; and to evaluate correlations between thickness of tissue before surgery, SNA, SNB, and ANB angles, and soft tissue changes. The study included 78 Class III patients treated only with BSSO or with BSSO and Le Fort I osteotomy. Lateral cephalograms were taken before and 3 months to 1 year after surgery. After all points of the Zagreb82 and Legan and Burstone profile analysis were traced, the ratio of five soft tissue points before and after surgery was evaluated. Soft tissue between points Sn and A and upper lip showed statistically significant changes for patients treated with bimaxillary surgery and BSSO. Only gender had an influence on soft tissue change. The correlation between soft tissue thickness and changes after surgery was significant. A change in SNB angle correlated with upper lip thickness for patients treated with BSSO but not for patients treated with BSSO and Le Fort I. SNA angle changes correlated with soft tissue changes between points Sn and A. Results of this study show soft tissue changes after BSSO and BSSO and Le Fort I and eliminate the deficiencies that were indicated in the meta-analysis of soft tissue changes from a previous study.

Craniofacial structure and body fat are key factors that predispose to upper airway obstruction while asleep, and these phenotypes can be genetically inherited. Neither the clinical characteristics of familial obstructive sleep apnoea syndrome (OSAS) nor the definitive morphological factors responsible for familial occurrence have been well identified. This study compared the clinical and cephalographic characteristics of Japanese patients with familial OSAS, non-familial OSAS and healthy controls, to clarify the mechanisms underlying familial OSAS. The study recruited 28 patients with familial OSAS, comprising 14 index cases and 14 first-degree relatives affected with OSAS, and compared these with age- and sex-matched patients with non-familial OSAS (n = 32) and healthy subjects (n = 33). Data on clinical status were collected, including the presence of hypertension, BMI and daytime sleepiness measured on the Epworth sleepiness scale. Respiratory function was evaluated by the AHI, % periods in which SpO(2) fell 90% or below and lowest value of SpO(2) on polysomnograms. Information on the first witnessed age of habitual snoring during sleep was collected via interview with patients and/or their family members. A detailed cephalometric assessment was made of each study subject. Patients with familial OSAS had lower mean BMI than did patients with non-familial OSAS. The first witnessed age of habitual snoring was younger in the familial cases than the non-familial cases. Cephalometric variables showed that the posterior airway space and the distance between the gonion and the gnathion were significantly smaller in the familial group than in the other two groups. Familial OSAS occurred at a younger age than non-familial OSAS due to minor anomalies of craniofacial morphology.

ObjectiveEvaluate the correlation between Friedman Tongue Position (FTP) and airway cephalometrics in patients with obstructive sleep apnea (OSA).Study DesignRetrospective review of adult patients with OSA undergoing Cone Beam Computed Tomography (CBCT).MethodsCollected data included age, sex, body mass index, apnea hypopnea index, FTP, and airway cephalometric parameters. Data analyses were performed using ANOVA, dichotomous t‐testing, and linear regression.Results203 patients were included in the analysis. (M:F 132:71). The mean posterior airway space (PAS) was inversely correlated (p = 0.001, r =.119) with higher FTP grades with means of 12.3 mm, 7.9 mm, 6.6 mm, and 4.3 mm, I‐IV respectively. Minimal cross‐sectional area for patients with FTP I‐IV was 245.7, 179.8, 137.6, and 74.2 mm, 2 respectively (p = 0.002, r = .095). Mean hyoid‐mandibular plane (H‐MP) for FTP I‐IV was 20.6 mm, 20.4 mm, 24.7 mm, and 28.9 mm respectively. No statistically significant difference between H‐MP values when comparing patients with FTP I or II (p = 0.22). There were statistically significant differences when these two groups were individually compared to FTP III and IV (p = 0.002). Linear regression analysis confirmed an independent association between FTP and PAS (β = −2.06, p < 0.001), minimal cross‐sectional area (β = −45.07, p = 0.02), and H‐MP (β = 3.03, p = 0.01) controlling for BMI, age, AHI, and sex.ConclusionsUse of FTP is supported by objective CBCT cephalometric results, in particular the PAS, minimal cross‐sectional area, and H‐MP. Understanding the correlation between objective measurements of retroglossal collapse should allow Otolaryngologists to more confidently select patients who may require surgery to address the retroglossal area, particularly when the ability to perform cephalometric analysis is not possibleLevel of Evidence4.

This study aimed to evaluate the accuracy of the Digital Imaging software in the prediction of soft tissue changes following three types of orthodontic interventions: non-extraction, extraction, and orthognathic surgery treatments. Ninety-six patients were randomly selected from the records of three orthodontic interventions (32 subjects per group): (1) non-extraction, (2) extraction, and (3) orthodontic treatment combined with orthognathic surgery. The cephalometric analysis of soft tissue changes in both the actual post-treatment and the predicted treatment was performed using Dolphin Imaging software version 11.9. A paired t-test was utilized to assess the statistically significant differences between the predicted and actual treatment outcomes of the parameters (p < 0.05). In the non-extraction group, prediction errors were exhibited only in the lower lip parameters. In the extraction group, prediction errors were observed in both the upper and lower lip parameters. In the orthognathic surgery group, prediction errors were identified in chin thickness, facial contour angle, and upper and lower lip parameters (p < 0.05). Digital Imaging software exhibited inaccurate soft tissue prediction of 0.3-1.0 mm in some parameters of all treatment groups, which should be considered regarding the application of Dolphin Imaging software in orthodontic treatment planning.

Obstructive sleep apnea (OSA) is a sleep-related breathing disorder characterized by a reduction or complete interruption of airflow during sleep, with episodes lasting at least 10 s. In severe cases, blood oxygen saturation can drop significantly, reaching levels as low as 40%. The aim of this study was to compare CAD/CAM-assisted maxillomandibular advancement (MMA) with traditional surgical techniques in the treatment of obstructive sleep apnea (OSA). We conducted a retrospective analysis of patients who underwent maxillomandibular advancement (MMA) for obstructive sleep apnea (OSA), all operated on consecutively by the same surgeon between 2022 and 2024 at the Maxillofacial Surgery of Policlinico Hospital San Camillo-Forlanini, Rome, Italy. This study included 18 patients with severe obstructive sleep apnea syndrome (OSAS) who underwent maxillomandibular advancement (MMA) surgery. The patients had a mean age of 38 years; 11 were male and 7 were female. Patients were divided into two groups: Group A, treated using a CAD/CAM-assisted surgical approach (five male and four female), and Group B, treated with conventional surgical techniques (six male and three female). Results: The comparison between preoperative and postoperative CT scans, along with 3D reconstructions using dedicated software, demonstrated a significant increase in airway volume following the skeletal repositioning. Notably, airway volume increased from 19.25 ± 0.5 mm3 to 26.14 ± 1.264 mm3 in group A and 20.564 ± 0.71 mm3 to 25.425 ±1.103 mm3 in group B. Conclusion: No significant differences were observed between the CAD/CAM-assisted and conventional surgical techniques for maxillomandibular advancement (MMA) in the treatment of severe obstructive sleep apnea (OSA). Both approaches led to a reduction in the apnea–hypopnea index (AHI) and an increase in posterior airway space (PAS). However, the use of software and digital planning through CAD/CAM technology allows for greater precision and shorter operative times, making the procedure more efficient overall.

BackgroundSeveral studies have shown soft tissue profile changes after orthodontic treatment in Class II Division 1 patients. However, a few studies have described factors influencing the soft tissue changes. The purpose of this study was to investigate the factors influencing the soft tissue profile changes following orthodontic treatment in Class II Division 1 patients.MethodsThe subjects comprised 104 Thai patients age 8–16 years who presented Class II Division 1 malocclusions and were treated with different orthodontic modalities comprising cervical headgear, Class II traction and extraction of the four first premolars. The profile changes were evaluated from the lateral cephalograms before and after treatment by means of the X-Y coordinate system. Significant soft tissue profile changes were evaluated by paired t test at a 0.05 significance level. The correlations among significant soft tissue changes and independent variables comprising treatment modality, age, sex, pretreatment skeletal, dental and soft tissue morphology were evaluated by stepwise multiple regression analysis at a 0.05 significance level.ResultsThe multiple regression analysis indicated that different treatment modalities, age, sex, pretreatment skeletal, dental and soft tissue morphology were related to the profile changes. The predictive power of these variables on the soft tissue profile changes ranged from 9.9 to 40.3 %.ConclusionsPrediction of the soft tissue profile changes following treatment of Class II Division 1 malocclusion from initial patient morphology, age, sex and types of treatment was complicated and required several variables to explain their variations. Upper lip change in horizontal direction could be found only at the stomion superius and was less predictable than those of the lower lip. Variations in upper lip retraction at the stomion superius were explained by types of treatment (R2 = 0.099), whereas protrusion of the lower lip at the labrale inferius was correlated with initial inclination of the lower incisor (L1 to NB), jaw relation (ANB angle), lower lip thickness and sex (R2 = 0.403). Prediction of chin protrusion at the soft tissue pogonion was also low predictable (R2 = 0.190) depending upon sex, age and initial mandibular plane angle (SN-GoGn). Additionally, age and sex also had mainly effect on change of the soft tissue profile in the vertical direction.

Introduction: This study aimed to evaluate the impact of long-term orthodontic treatment with and without teeth extractions in soft tissue and dentoskeletal variables. Methods: The sample was comprised of cephalometric radiographs of forty patients orthodontically treated with and without premolar extractions. The patients were evaluated in pretreatment (T1); posttreatment (T2) and long-term follow-up (T3) times. Two groups were formed according to the protocol treatment. The Extraction Group: 24 patients (16 female, 8 male), with mean ages of 13.14 (T1), 15.50 (T2), and 52.49 years (T3). Mean treatment time (T2-T1) and long-term follow-up (T3-T2) of 2.36 and 36.99 years, respectively. The Nonextraction Group: 16 patients (10 female, 6 male), with mean ages of 15.18 (T1), 17.03 (T2), and 53.61 years (T3). Mean treatment time (T2-T1) and long-term follow-up (T3-T2) of 1.85 and 36.58 years, respectively. The cephalometric analysis of soft tissue and dentoskeletal was performed using Dolphin Imaging Software. The independent t test was used for intergroup comparisons. Results: The nonextraction group had a short treatment time (p=0.31). The extraction group showed significant mandibular incisor retraction during the treatment (p=0.019). Both groups presented similar changes in soft tissue and dentoskeletal variables after long-term follow-up. Conclusions: The orthodontic treatment with and without extractions presented similar changes in soft tissue and dentoskeletal variables after a 37-year follow-up.

Background and Objectives: Obstructive sleep apnea is an extremely diffuse pathology that, if left untreated, can lead to very serious cardiovascular consequences. The primary goal of treatment is to maintain airflow in the upper airway tract, which can be obtained thanks to orthognathic surgery such as maxillo-mandibular advancement (MMA). This procedure increases the volume of the posterior airway space (PAS)-a parameter considered fundamental in OSA physiology. However, the correlation between the degree of advancement, the volume increase, and the clinical improvement in OSA is not yet clear, even in patients who undergo virtual surgical planning. Aiming to test the correlation of these parameters and the role of PAS volume changes, we present our pre- and post-operative volumetric analysis of the PAS using cone beam computed tomography (CBCT) following CAD/CAM-assisted maxillomandibular advancement. Materials and Methods: We collected information from patients who underwent MMA for moderate or severe OSA, planned virtually with custom-made devices, between 2020 and 2022 at the Maxillofacial Surgery and Odontostomatology Unit of the Policlinico Hospital in Milan. The degree of mandibular advancement (pogonion antero-posterior advancement) was noted. All patients underwent pre- and post-operative CBCT and pre- and post-operative polysomnography to measure the Apnea-Hypopnea Index (AHI) parameters. Both exams were performed within six months before and after surgery. The surgeries were planned virtually along with the production of custom-made devices (cutting guides and mandibular osteosynthesis plates). Volumetric analysis of the PAS was performed pre- and post-CBCT images using medical segmentation software (Mimics, Materialise, Mimcs 26.0). Results: Ten patients (nine men and one woman) with a mean age of 51 years were included in this study. The mean pogonion advancement was 14.5 mm, ranging from 13.8 to 15.6. The mean pre-surgical AHI was 52.31 events/h, while the mean post-surgical AHI was 5.94 events/h (SD 5.34). The improvement in AHI was statistically significant (Wilcoxon matched-pairs signed-rank test, p value 0.004). The mean pre-surgical PAS volume was 8933 mm3, while the mean post-surgical volume was 10,609 mm3. In 8 out of 10 patients, the volume increased, with a mean increase of 2640 mm3 (max. 5183, min. 951), corresponding to a percentage increase variation ranging from 78% to 6%. In two patients, the volume decreased by 1591 (-16%) and 2767 mm3 (-31%), respectively. The difference between pre- and post-operative results was not statistically significant (paired t-test, p value 0.033). Conclusions: The results obtained confirm the efficacy of virtually planned MMA performed with custom-made devices in OSA therapy. However, they also show that PAS volume should not be used as a comprehensive parameter for OSA treatment evaluation because it does not always have a positive correlation with advancement and AHI.