Impact of the orofacial muscular rehabilitation exercise on facial expression recovery post-orthognathic surgery.

OBJECTIVE: This study aimed to evaluate the impact of myofunctional rehabilitation of the orofacial muscles through specific exercises on the recovery of facial expression in patients following orthognathic surgery. MATERIAL AND METHODS: The study included 62 patients who underwent Le Fort I and sagittal split ramus osteotomy (SSRO). Patients were divided into two groups: the first group started immediate post-operative myofunctional rehabilitation of the orofacial muscles through specific exercises. In contrast, patients in Group II did not undergo any myofunctional rehabilitation post-operative exercises. The recovery of facial expressions postoperatively was evaluated in both calm and smiling states by comparing the differences between 3D facial scanning data of chosen facial anatomical structures collected at five key time points: pre-surgery (D0), 2 days (D2), 14 days (D14), 1 month (D30), and 3 months (D90) postoperatively. RESULTS: The analysis revealed that characteristic angles and lengths experienced significant changes post-surgery, with ∠chRnchL and ∠chRsnchL decreasing at D2 and normalizing by D30 in the experimental group, while the control group showed a slower recovery, normalizing by D90. The ChL-R length decreased at D2, returning to normal by D30 in the experimental group and D90 in the control group. The height Li-Ls increased at D2 and normalized by D30 in calm and smiling expressions across single and double jaw surgery patients. These findings underscore the more rapid recovery in the experimental group compared to the control group (P < 0.05; P < 0.005; P < 0.0001). CONCLUSION: Initiating myofunctional rehabilitation immediately following orthognathic surgery enhances facial muscle function recovery, improves patient confidence, and expedites social reintegration. This approach is crucial for functional and psychological benefits.

Single vs. Double-Opposing Z-Plasty: Evaluating Their Impact on Palatoplasty Postoperative Outcomes.

BACKGROUND: The double-opposing Z-plasty is a fundamental approach for cleft palate repair. Recently, some surgeons have begun implementing a single Z-Plasty, igniting discussions on the most effective technique for enhancing postoperative outcomes. Consequently, this study sought to evaluate the outcomes of employing single and double Z-plasties within the modified Sommerlad-Furlow technique. METHODS: 116 cleft palate patients undergoing primary surgical repair were divided into two groups: those treated with the Sommerlad-Furlow method using a double-opposing Z-plasty (S.F.2.Z.P. group, n = 58) and those receiving a single nasal Z-plasty (S.F.1.Z.P. group, n = 58). Data on cleft type and width, soft palate length, palatal fistula, and velopharyngeal function were collected. Mann-Whitney test compared the mean values between groups. RESULTS: The S.F.2ZP group demonstrated a statistically significant increase in soft palate length compared to those in the S.F.1ZP group (p = 0.008). However, the S.F.1ZP group demonstrated adequate soft palate length (7.9 ± 2.8 mm) compared to the S.F.2ZP group (9.3 ± 2.8 mm). The velopharyngeal function was good in both groups, with no significant differences (P = 0.52). While the proper velopharyngeal closure was 81% in the S.F.1ZP group and 87.9% in the S.F.2ZP group, velopharyngeal insufficiency was 10.3% and 5.2%, respectively. The rates of persistent palatal fistula were 5.2% in the S.F.1ZP group and 3.4% in the S.F.2ZP group, with no significant differences found between both groups (P = 0.64). CONCLUSIONS: There were no significant differences in crucial outcomes such as velopharyngeal function and the incidence of persistent palatal fistulas, indicating the effectiveness of both techniques. While the double-opposing Z-plasty demonstrated a statistically significant increase in soft palate length, the a nasal Z-plasty demonstrated adequate soft palate length which sufficiently enables effective velopharyngeal closure. These outcomes suggest that a single Z-plasty is both effective and easy to perform, making it a valuable surgical approach for achieving the desired outcomes.. CLINICAL RELEVANCE: The current study suggests that although the soft palate may not be as elongated with nasal Z-plasty alone compared to the double Z-plasty, it sufficiently enables effective velopharyngeal closure.

Comparison of the biomechanical behavior between commercial and 3D-printed patient-specific Ti6Al4V L-Shaped titanium plates following le fort i osteotomy using finite element analysis: A technical Note.

OBJECTIVE: To evaluate and compare the biomechanical behavior of three-dimensionally (3D) printed patient-specific Ti6Al4V with commercially made titanium mini plates following Lefort-I osteotomy using finite element analysis. METHODS: Le Fort I osteotomy was virtually simulated with a 5 mm maxillary advancement and mediolateral rotation in the coronal plane, resulting in a 3 mm gap on the left side's posterior. Two fixation methods were modeled using software to compare 3D-printed Ti6Al4V and commercial titanium mini plates, both featuring a 4-hole l-shape with thicknesses of 0.5 mm and 0.7 mm at the strategic piriform rim and zygomaticomaxillary buttress locations. Using ANSYS R19.2, finite element models were developed to assess the fixation plates and maxilla's stress, strain, and displacement responses under occlusal forces of 125, 250, and 500 N/mm². RESULTS: This comparative analysis revealed slight variation in stress, strain, and displacement between the two models under varying loading conditions. Stress analysis indicated maximum stress concentrations at the vertical change in the left posterior area between maxillary segments, with the Ti6Al4V model exhibiting slightly higher stress values (187 MPa, 375 MPa, and 750 MPa) compared to the commercial titanium model (175 MPa, 351 MPa, and 702 MPa). Strain analysis showed that the commercial titanium model recorded higher strain values at the bending area of the l-shaped miniplate. Moreover, displacement analysis revealed a maximum of 3 mm in the left posterior maxilla, with the Ti6Al4V model demonstrating slightly lower displacement values under equivalent forces. CONCLUSION: The maximum stress, strain, and segment displacement of both fixation models were predominantly concentrated in the area of the gap between the maxillary segments. Notably, both fixation models exhibited remarkably close values, which can be attributed to the similar design of the fixation plates.

The effect of different hybrid rigid internal fixation techniques on the postoperative stability following a mandibular advancement using a bilateral sagittal split ramus osteotomy: A retrospective three-dimensional comparative study.

OBJECTIVE: To three-dimensionally evaluate post-operative mandibular stability following bilateral sagittal split ramus osteotomies between hybrid and non-hybrid rigid internal fixation techniques. MATERIALS AND METHOD: Seventy adults with skeletal class II deformity who underwent bilateral split sagittal osteotomy with mandibular advancement were included. Patients were divided into four groups based on their fixation techniques: hybrid technique (HT) groups I, II, and IV received a 4-hole 2 mm miniplate with either a bicortical screw (BS), additional 2 mm 4-hole miniplate, or two-hole miniplate, while non-HT group III received a 4-hole 2 mm miniplate with four mini-screws (MS). Measurements were taken pre-operatively (T0), immediately postoperatively (T1), and ≥1 year after surgery (T2) using 3D Slicer software. RESULTS: Age, sex, and follow-up period did not correlate significantly with postoperative relapse or stability. Significant differences were observed in the advancement on the right side between groups II, III, and IV and on the left side between groups I, III, and IV. However, the type of surgical intervention showed no significant effect on postoperative relapse and stability. All groups of fixations showed satisfactory stability with irrelevant relapse (< 2 mm or 2°). CONCLUSION: The study demonstrated satisfactory and comparable stability among different fixation groups on patients undergoing mandibular advancement following bilateral split sagittal osteotomy. The results highlighted the importance of considering the degree of advancement when planning orthognathic surgery and managing postoperative outcomes.

Does adjunctive fixation in conjunction with miniplate affect condylar position and morphology after mandibular advancement through bilateral sagittal split ramus osteotomy? A retrospective 3-dimensional CT comparative study.

To minimize condylar positional and morphological changes after mandibular advancement through bilateral sagittal split ramus osteotomy (BSSRO), surgeons add either a bicortical screw or a two-hole plate distal to the conventional single miniplate. Since there have been no previous studies investigating the effect of this combination, our study aimed to evaluate the short- and long-term effects of these adjunctive fixation methods (AFM) on condylar positional and morphological changes after mandibular advancement through BSSRO. This retrospective cohort study included consecutive patients with retruded mandibles who were treated in the Department of Orthognathic and TMJ Surgery at West China Hospital of Stomatology, Sichuan University. The patients were divided into two groups based on the primary predictor variable, which was the addition of AFM - either a single bicortical screw or a two-hole plate in addition to the single miniplate. The primary outcome variable was the condylar positional and morphological changes after mandibular advancement through BSSRO. Three-dimensional facial CT scans were obtained at three different time points (preoperatively - T0, 1 week postoperatively - T1, and 1 year postoperatively - T2) and analyzed using ITK-SNAP, 3D Slicer, and SlicerSALT software. Intergroup comparisons were conducted with an independent t-test, with a p-value of <0.05 considered significant. Correlations between the variables were estimated by Pearson correlation. The study comprised 51 patients (32 females, 19 males; mean age 25.13 ± 4.24 years), involving a total of 81 condyles (21 unilateral and 60 bilateral). There was a significant difference in long-term condylar displacement in favor of AFM along with a single miniplate (p < 0.001). The bicortical screw group recorded less condylar displacement than the two-hole plate group horizontally (0.11 mm vs 0.22 mm) and sagittally (0.03 mm vs 0.17 mm), but more vertically (0.85 mm vs 0.03 mm). Bone formation associated with AFM occurred on all condylar surfaces, compared with only three surfaces in the single miniplate group. The adjunctive method in addition to the single miniplate fixation method showed less condylar displacement and more bone apposition after mandibular advancement through BSSRO. The follow-up duration variable was the only significant determinant for volumetric changes in the condyle.

Bone Volume Analysis and Associated Influencing Factors in Mandibular Distraction Osteogenesis: A Retrospective Analysis.

BACKGROUND: Distraction osteogenesis is a progressively popular technique for maxillofacial bone reconstruction, but there is a notable gap in the analysis of bone volume within the distraction segment and the exploration of associated influencing factors. PURPOSE: The purpose of this study was to quantitatively analyze the new bone volume and the distraction gap volume in the three-dimensional (3D) model and explore the influencing factors associated with the percentage of the new bone volume to the distraction gap volume. STUDY DESIGN, SETTING, SAMPLE: This retrospective study included patients who underwent maxillofacial distraction osteogenesis treatment at the West China Hospital of Stomatology between 2014 and 2022, utilizing the mandibular distractor (Cebei, Ningbo, China). Exclusion criteria encompassed individuals with incomplete clinical or radiographical records as well as those who loss to follow-up. PREDICTOR VARIABLE: The predictor variables were age, sex, diagnosis, consolidation period duration, distraction modality, osteotomy area, distraction gap volume, and proximal bone segment volume. MAIN OUTCOME VARIABLE(S): The outcome variable was osteogenic effect which defined as the percentage of the new bone volume to the distraction gap volume in the 3D model. COVARIATES: Not applicable. ANALYSES: T-tests were used to describe categorical variables, and Pearson correlation analysis was used to describe continuous variables. Linear regression was employed to assess the predictiveness of variables for osteogenic effect. Data are described as mean ± standard deviation; statistical significance was established at a P value < .05. RESULTS: The study sample contained 35 patients(11 males and 24 females) with a mean age of 21.17 ± 11.82 years (range: 5 to 47 years) were included. The mean osteogenic effect of all samples was 78.89 ± 24.70%. Multiple linear regression models confirmed that the osteogenic effect was significantly influenced by the distraction gap volume (P = .003), proximal bone segment volume (P = .009), osteotomy area (P = .034), diagnosis (P = .004), and distraction modality (P = .021). CONCLUSION AND RELEVANCE: The percentage of new bone mass to simulated volume based on 3D model measurement can serve as an effective quantitative indicator for evaluating the osteogenic effect; our study demonstrates that distraction gap volume, proximal bone segment volume, osteotomy area, diagnosis, and distraction modality can statistically significantly influence the osteogenic effect.

Arthroscopic reduction and rigid fixation of the anteriorly displaced temporomandibular joint disc without reduction using titanium screw: a case series.

OBJECTIVES: To evaluate the effectiveness of arthroscopic reduction and rigid fixation (ARRF) using a suture-free titanium screw as a treatment approach to temporomandibular joint's (TMJ) anterior disc displacement without reduction (ADDwoR) and assess its impact on clinical outcomes, including improvements in symptoms related to TMJ disorders. MATERIALS AND METHODS: A series of twenty patients presented to the Department of Orthognathic and Temporomandibular Surgery at West China Hospital of Stomatology between September 2022 and January 2023, complaining of symptoms such as pain, clicking, and limited mouth opening. Standard magnetic resonance image (MRI) imaging T1 and T2 sequences in both sagittal and coronal views study with closed and maximal open mouth positions were taken preoperatively to assess the disc's position, integrity, and shape. Also, cone-beam computed tomography (CBCT) scans images to find any degenerative changes and evaluate the condylar bone's features and volume. Additionally, the clinical examination assesses limited oral opening, mechanical pain, and the presence of any noises such as clicking and crepitus. All cases were treated under general anesthesia using the arthroscopic release, reduction, and rigid fixation of the TMJ's ADDwoR to establish a normal disc-condyle relationship and to restore the functional position. RESULTS: Patients' symptoms, such as pain and mouth opening, improved significantly following the arthroscopic treatment. Postoperative MRI and CBCT imaging follow-up conducted at 6 months demonstrated the stable position of the reduced TMJ disc and the fixation screw. Notably, none of the patients exhibited signs of relapse during this follow-up period. CONCLUSION: Overall, the ARRF of TMJ's ADDwoR using a suture-free titanium screw proved to be safe and provides satisfactory results, in addition to the several advantages of using suture-free titanium screws, such as biocompatibility, strong fixation, and durability. However, it is a technically demanding procedure requiring extensive, long-term training. CLINICAL RELEVANCE: ARRF using a cost-effective fixation titanium screw to treat ADDwoR emerges as a clinically effective minimally invasive approach.

Interspecies comparison of temporomandibular joint condylar cartilage extracellular matrix from macro to microscopy.

Interspecies comparisons of the extracellular matrix of temporomandibular joint (TMJ) condylar cartilage are necessary to elucidate the mechanisms underlying its superior mechanical properties, to guide the construction of animal models of TMJ-related diseases, and to establish standards for the engineering of TMJ condylar cartilage. Here we characterize and compare TMJ condylar cartilage from six different species from a materials science perspective, including structure, composition and mechanical properties from the macroscopic to the microscopic level. The gross morphology showed obvious interspecies differences in size and shape, which may be related to the different joint motion patterns. Although the condylar cartilage of all species can be divided histologically into a superficial fibrous layer and a deep hyaline layer, there are significant interspecies differences in the microstructure of the fibrils in the two layers, mainly in the diameter of the fibrils. Compositionally, there were no significant differences in collagen composition between species, but the content of glycosaminoglycans (GAGs) decreased progressively with increasing body size, with the same results obtained by Safranin O staining and biochemical analysis. Mechanically, the elastic modulus of mouse condylar cartilage was significantly higher than that of the other species and tended to decrease with increasing body size. This study shows that the TMJ condylar cartilage of different species has its own specific structure-composition-mechanics matching characteristics for their unique masticatory stress dissipation, and differences in fibril diameter and GAGs content may be the two ultimate factors influencing the differences in cartilage mechanical properties between species, while the condylar cartilage of pigs is most similar to that of humans, suggesting that pigs may be a suitable animal model for TMJ studies.

Condylar positional changes and remodeling following bimaxillary anterior segment osteotomy with and without Le Fort I osteotomy: a three-dimensional comparative analysis.

OBJECTIVE: To evaluate 3D condylar displacement and long-term remodeling following the correction of bimaxillary protrusion by anterior segment osteotomy (ASO) with and without Le Fort I surgery. MATERIALS AND METHOD: This retrospective study included 32 adults with bimaxillary protrusion who underwent ASO alone (group 1) or with concomitant Le Fort I osteotomy (group 2). Subject's computed tomography scans at basic (T0), immediate postoperatively (T1), and at 1 year or more follow-up (T2) were collected. The condyle displacement was measured at superior-inferior, lateromedially, and anteroposterior surfaces, while condyle remodeling was measured at the superior, lateral, anterior, medial, and posterior surfaces. All 3D analyses were performed using 3D Slicer software (4.11.2). RESULTS: At T1, 52.7%, 86.7%, and 94.4% of condyles in group 1 were displaced inferiorly, laterally, and posteriorly, respectively, as well as 75%, 89.2%, and 53.5% of condyles in group 2, which had not fully returned to the original preoperative positions at T2. Condylar remodeling was observed in both groups at T2, and no significant difference was found in the overall condylar volume between T1 and T2 in both groups. Patients in group 2 exhibited significant bone resorption at both lateral and anterior surfaces compared to group 1 (P = 0.000 and 0.01, respectively). CONCLUSION: This study's results demonstrated that ASO is associated with a degree of condylar changes even if the posterior mandible is not osteomized. The positional changes vary between bimaxillary ASO alone and those with simultaneous Le Fort I osteotomy. However, both groups' condyle volume remained stable at the long-term follow-up.

TMJ anterior disc displacement anchorage surgery: a retrospective study based on a suture-free titanium screw strategy.

OBJECTIVE: To evaluate the feasibility and effectiveness of using a suture-free titanium screw in repositioning anterior disc displacement without reduction (ADDwoR) of the temporomandibular joint (TMJ). METHODS: A consecutive sample of twelve patients (fifteen joints) was included in this study. All patients were diagnosed with ADDwoR and showed limited mouth opening or temporomandibular joint pain symptoms. Suture-free titanium screw was placed in the condyle directly following the disc repositioning. Pre- and postoperative evaluation parameters include operation time, the visual analogue scale for pain (VAS), lateral excursion movements (LEM), maximum interincisal opening (MIO), and disc length and position on MRI. In addition, the mandibular condyle height was also measured. Statistical significance was considered when p < 0.05. RESULTS: The unilateral operation time was 58.54 ± 5.43 min; during the 6-month period after the operation, the VAS values decreased from 87 ± 6.34 to 14.08 ± 6.65. The MIO increased from 30.07 ± 4.73 to 39.89 ± 1.69 mm (p = 0.01). The TMJ disc length was prolonged from 8.23 ± 1.12 to 11.51 ± 1.29 mm. The condyles showed significant remodeling, and the height of the condyle increased from 18.24 ± 4.12 increase to 19.6 ± 4.31 mm. The LEM was increased from 5.27 ± 0.51 to 6.36 ± 0.62 mm. The MRI images showed the stability of the disc in position during the opening and closing of the mouth. The TMJ disc position was stable during the follow-up period. CONCLUSION: Anteriorly displaced articular disc can be repositioned by a suture-free titanium screw strategy. This technique is an alternative method to address ADDwoR.

Maxillary sinus volume and facial asymmetry after unilateral zygomaticomaxillary complex fracture reduction with 2, 3, and 4 fixation points: CBCT-based investigation.

PURPOSE: This study aimed to assess the maxillary sinus volume (MSV), Chronic Sinusitis incidence, and asymmetry of the zygomaticomaxillary complex (ZMC) following ZMC fracture surgery with various numbers of fixation points. MATERIALS AND METHODS: In a prospective non-randomized cohort, 50 adults with unilateral ZMC fractures who treated by open reduction and internal fixation (ORIF) between November 2019 and October 2021 were assigned to accomplish this study. They distributed into three groups as per fixation points (2, 3, or 4 Points). Preoperative (T1), Immediate postoperative (T2), and follow-up (T3) cone beam computed topography were analyzed using the Mimics software. The main measures were MSV and asymmetry indexes (ASI) of six paired bilateral anatomical landmarks (Orbital, Suprajugal, Jugale, Zygon, Maxillozygion 1, and Maxillozygion 2). RESULTS: MSV decreased significantly on the affected sides postoperatively in 2P and 3P groups, both in T2 and T3. Further, the T2-T3 comparisons showed a significant MSV change (p = 0.001). ASI reduced considerably to clinically tolerated levels (<3 mm) on landmarks near the fixation sites postoperatively. The ASI on the Zygon and Maxillozygion 1 landmarks showed significant changes among the three groups in both T2 and T3. Interestingly, only five cases had reported postoperative sinusitis symptoms. CONCLUSIONS: Although the MSV was changed among the different fixation point groups, the incidence of chronic sinusitis was uncommon. Bilateral asymmetry affected by number and position of the fixation points, fixation with 4 points provide more symmetry.

Effect of the magnitude of condylar head displacement on the TMJ function in skeletal class II patients undergoing different degrees of mandibular advancement: A retrospective comparative study.

PURPOSE: This study aimed to compare the condylar head displacement (CHD) after bilateral sagittal split ramus osteotomy (BSSO) between different degrees of mandibular advancement in skeletal class II patients and to evaluate whether the temporomandibular joint (TMJ) function would be affected. PATIENTS AND METHODS: Fifty-nine patients (118 condyles) were included in this retrospective study and were divided into three groups based on the distance of mandibular advancement. The CHD in three directions, x (sagittal direction), y (coronal direction), and z (axial direction), was measured before operation (T0), immediately after operation (T1), and at least 6 months after operation (T2), and the TMJ function of patients was followed up and scored using the Helkimo index system. All the abovementioned data were statistically analyzed, and p < 0.05 was considered the statistical difference standard. RESULT: During the BSSO surgery, the condyle was predominantly displaced in a lateral, posterior, and superior direction whenever in T1 and T2, even though the degree of CHD was different. Regarding the amount of CHD, the large advancement group was higher than the other two groups in T1 and T2 (p＜0.01). The Helkimo index scores of the three groups were evaluated, and there was no significant statistical difference between the Ai and Di index of the three groups. CONCLUSION: In our center, CHD occurred in lateral, posterior, and superior directions following mandibular advancement in skeletal class II patients, with a positive correlation between the CHD and the mandibular advancement; however, the TMJ function of the three groups did not show significant differences.

Development of postoperative velopharyngeal function in patients with cleft palate.

OBJECTIVE: Patients with a cleft palate often experience a velopharyngeal dysfunction known as velopharyngeal insufficiency (VPI). The purpose of this study was to examine the development of velopharyngeal function (VPF) following primary palatoplasty and the factors that are linked to it. METHODS: A retrospective study was conducted to examine the medical records of patients who had cleft palate, with or without cleft lip (CP ± L) and underwent palatoplasty at a Tertiary Affiliated Hospital between 2004 and 2017. Postoperative evaluation of VPF was conducted at two follow-up times (T1, T2) and was classified as either normal VPF, mild VPI, or moderate/severe VPI. The consistency of VPF evaluations between the two time points was then assessed, and patients were categorized into either the consistent or inconsistent group. The study collected and analyzed data on gender, cleft type, age at operation, follow-up duration, and speech records. RESULTS: The study included 188 patients with CP ± L. Out of these, 138 patients (73.4%) showed consistent VPF evaluations, while 50 patients (26.6%) showed inconsistent VPF evaluations. Among those with VPI at T1 (91 patients), 36 patients (39.6%) had normal VPF at T2. The rate of VPI decreased from 48.40% at T1 to 27.13% at T2, whereas the rate of normal VPF increased from 44.68% at T1 to 68.09% at T2. The consistent group had a significantly younger age at operation (2.90 ± 3.82 vs 3.68 ± 4.02), a longer duration of T1 (1.67 ± 0.97 vs 1.04 ± 0.59), and a lower comprehensive score of speech performance (1.86 ± 1.27 vs 2.60 ± 1.07) than the inconsistent group. CONCLUSIONS: It has been verified that there are changes in the development of VPF over time. Patients who underwent palatoplasty at a younger age were more likely to have confirmed VPF diagnosis at the first evaluation. The duration of follow-up was identified as a critical factor that affects the confirmation of VPF diagnosis.

An early microvascular training program of dental intern students and junior residents: a comparative prospective study.

BACKGROUND: Clinical instructional strategies and the climate in which teaching and learning take place have a significant impact on the quality of dental education. Therefore, this study aimed to evaluate the impact of early microsurgery training on the skills of dental intern students who are planning to join an oral and maxillofacial surgical field (DIS) as compared with junior residents within an oral and maxillofacial surgery department who had no microsurgery experience (JR). METHODS: A total of 100 trainees, 70 were DIS, while the other 30 were JR. The average age was 23.87 ± 2.05 years for DIS group and 31.05 ± 3.06 for JR group. All trainees attended a microsurgical course (theoretical and practical parts) for seven days within a Microvascular Laboratory for Research and Education of a university-affiliated tertiary hospital. Two blinded examiners had assessed the performance of trainees independently using a specific scoring system. The independent sample t-test was used to compare the effect of microsurgery training between DIS and JR groups. The significance level was set at 0.05. RESULTS: The DIS group had showed higher attendance rate than JR group (p < 0.01), with a lower absence score in DIS than JR groups (0.33 ± 0.58 vs. 2.47 ± 1.36). The total score of the theoretical test was significantly different between both groups (p < 0.01). In this context, the DIS group had revealed higher total score than JR group (15.06 ± 1.92 vs. 12.73 ± 2.49). In term of tissue preservation, there was a significant difference between both groups, with the DIS had better performance score than JR (1.49 ± 0.51 vs. 0.93 ± 0.59). Further, the practical exam score was significantly higher in DIS group than JR group (p < 0.01). CONCLUSION: Overall, the performance of dental intern students was favourably compared with junior residents in most aspects. Therefore, it is promising and essential for dental colleges to add a microsurgery course to the curriculum of dental intern students who plan to specialize in oral and maxillofacial surgery.

Lower lip reconstruction using McGregor fan technique with or without depressor anguli oris chimeric flap. Is there a difference in function and aesthetic outcomes?

BACKGROUND: Lower lip reconstruction aims to maintain facial subunit function and aesthetics. We present a minor modification of the McGregor flap technique, in which depressor anguli oris (DAO) muscle is separately elevated as a chimeric flap together to investigate the outcomes for reconstructing lower lip defects using various functional parameters. METHODS: The study included patients who underwent surgical repair of lower lip defects using a McGregor fan flap with or without DAO muscle chimeric flap between January 2018 and May 2021. The patients were divided into our modified technique with DAO chimeric flap (study group) and conventional McGregor (control group). The primary outcomes were functional evaluation of oral competency, speech intelligibility, and tactile sensation of reconstructed lip outcomes. The functional satisfaction and Patient and Observer Scar Assessment Scale (POSAS) were analyzed. RESULTS: A total of 20 patients were enrolled (10 patients for each group). Excellent oral competence was present in 12 patients, favorably significant in patients with DAO chimeric flap (n = 8/10, p = 0.018). All patients had intelligible speech with insignificant differences between the two groups. No patients demonstrated differences to light touch from baseline sensation at 1 year. Patients in the study group reported more lip function satisfaction (p = 0.049). The POSAS score indicates satisfaction with the appearance of all patients. CONCLUSION: McGregor fan technique combined with DAO muscle chimeric flap offers a good choice by maintaining sensory and motor functions. Our minor modification can ensure the integrity of the oral sphincter, leading to improved lower lip function.

Evaluation of Postoperative Outcomes in Two Cleft Palate Repair Techniques without Relaxing Incisions.

BACKGROUND: A modified palatoplasty was established by incorporating the designs of both Sommerlad and Furlow techniques in addition to a novel incision on the medial pterygoid plate's surface, named the Sommerlad-Furlow modified technique. Thus, this study aimed to evaluate the clinical and functional outcomes of the Sommerlad-Furlow modified technique against an accepted standard, the Furlow technique. METHODS: A retrospective review was conducted for 212 consecutive nonsyndromic cleft palate patients who underwent Sommerlad-Furlow ( n = 106) and Furlow ( n = 106) repairs without relaxing incision on the hard palate between 2011 and 2016. The success of surgical procedures was estimated by the rate of postoperative fistula, speech outcomes, and velopharyngeal insufficiency (VPI)-related quality of life. The demographic and surgical data, including sex, age, cleft type, cleft width, and follow-up period were recorded. RESULTS: There was no statistically significant difference between the two treatment groups regarding demographic and surgical data, except the cleft width ( P < 0.001). The incidence of the fistula was 7.5% and 6.6% after the Sommerlad-Furlow and Furlow procedures, respectively. The two groups showed no significant differences in speech outcomes, and adequate velopharyngeal function was found in 84% and 82.1% in Sommerlad-Furlow and Furlow procedures, respectively. Besides, the rate of severe VPI was slightly lower in Sommerlad-Furlow (0.9%) than in Furlow (2.8%) procedures. Moreover, an adequate VPI-related quality of life was found in 80.4% of the Sommerlad-Furlow group and 78.6% of the Furlow group. CONCLUSION: The Sommerlad-Furlow technique has obtained acceptable postoperative outcomes and could be a choice for cleft palate repair, especially in wider clefts. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Three dimensional condylar positional and morphological changes following mandibular reconstruction based on CBCT analysis: a prospective study.

OBJECTIVE: This study aimed to evaluate the condylar positional changes following mandibular reconstruction with preservation of the condylar head using Cone-Beam Computed Tomography (CBCT). Also, to assess joint space changes and the overall volumetric space compared to the preoperative status. METHODOLOGY: This prospective study included 30 patients (60 joints) subjected to unilateral mandibular resection and reconstruction with preservation of the condylar head. The Helkimo index and preoperative (T1), two weeks postoperative (T2), and follow-up CBCTs (T3) after at least six months were gathered and processed to evaluate the condylar position and TMJ joint space using Anatomage Invivo 6. A student's t-test and repeated-measures ANOVA statistics were used. A P value of less than 0.05 was considered statistically significant. RESULTS: Thirty patients (14 males, 16 females) with a mean age of 40.01 ± 12.7 years (a range of 18.1-62.9 years) were included. On the tumor side, there were significant variances in the vertical and mediolateral condylar positions between the three-time points (T1, T2, T3). Immediately after the operation, the condyles were significantly displaced in a downward direction at T2, which became larger after the last follow-up period (T3) (p = 0.007). The condylar positions at the anteroposterior direction were relatively stable without significant differences between the three times points (p = 0.915). On the non-tumor side, the condylar positions were relatively stable in the mediolateral and anteroposterior positions. In the tumor side, all of the TMJ spaces were significantly increased in size following the mandibular reconstructions (T2 and T3). However, on the non-tumor side, the anterior, posterior, and medial joint spaces were significantly changed postoperatively. CONCLUSION: After mandibular reconstruction with condylar preservation, the condylar position and volumetric measurement immediately changed noticeably and continued to be a permanent change over time compared to relatively stable condyles on the non-tumor side. According to Helkimo index, patients become adapted to the postoperative changes without significant differences between the two sides.

Evaluation of the Properties of 3D-Printed Ti Alloy Plates: In Vivo and In Vitro Comparative Experimental Study.

Titanium (Ti)-based implants play a significant role in rigid internal fixation in maxillofacial surgery. No study has reported that three-dimensional-printed Ti alloy plates (3D-Ti plates) have comprehensively excellent properties similar to standard plates (Matrix-MANDIBLE, SYNTHES, Switzerland) (Synthes-Ti plates). In this work, we manufactured 3D-Ti plates by selective laser melting with Ti6Al4V powder. The surface morphology, mechanical properties, and bone-plate contact rate of the 3D-Ti plates and the Synthes-Ti plates were characterized and compared via electron microscopy, atomic force microscopy, Vickers hardness test, three-point bending test, and software calculation. Human bone marrow stromal cells (HBMSCs) were cultured on the plates to test their biocompatibility. Importantly, the 3D-Ti plates were placed into a mandibular fracture model to assess the effect of medical application for 4 and 24 weeks. The 3D-Ti plates were demonstrated to have similar biocompatibility and stability for rigid internal fixation with the Synthes-Ti plates, lower roughness (106.44 ± 78.35 nm), better mechanical strength (370.78 ± 1.25 HV10), and a higher bone-plate contact rate (96.9%). These promising results indicate the feasibility of using 3D-Ti plates for irregular shapes and complex anatomical structures in a clinical context.

Correlation between mandibular anatomy and bad split occurrence during bilateral sagittal split osteotomy: a three-dimensional study.

OBJECTIVES: This study aimed to find out the correlation between different anatomical parameters of the mandible and the occurrence of a bad split in patients who had undergone bilateral split sagittal ramus osteotomy (BSSRO). MATERIALS AND METHOD: At both the distal roots of the first molar (1) and the retromolar area (2), we measured the distance from the buccal margin of the inferior dental canal (IDC) to the buccal margin of the cortical bone (MCBC), the thickness of both buccal cortical (WBCB) and cancellous bone (WBCA), distance from the superior border of IDC to the alveolar crest (MCAC), buccolingual thickness (BLT), and thickness of cancellous bone (WCA). At the ramus, the distances between the sigmoid notch to the upper part of the lingula (SL) and the inferior border of the mandible (SIBM), the thickness of the ramus at the level of the lingula (BLTR), and the anteroposterior width of the ramus (APWR) were measured. The paired and independent t-tests were used when applicable, and a P-value < 0.05 was considered significant. RESULTS: MCBC1 showed a significant difference between bad and non-bad split sides (P = 0.037). Both WBCA1 and WBCA2 show the same significant difference (P = 0.023, 0.024). Similarly, WCA1 and WCA2 showed a statistical difference between the bad and non-bad split sides (P = 0.027, 0.036). There were no statistically significant differences between the compared sides of WBCB1, WBCB2, MCAC1, MCAC2, SIBM, APWR, SL, and BLTR. CONCLUSION: Narrow space between IDC and the buccal cortical margin, along with the decrease in the thickness of both buccal cancellous bone and total cancellous bone at the inferior border of the mandible along the course of SSRO, has been implicated in the occurrence of bad split intraoperatively.

Influence of Inferior Alveolar Nerve Exposure During Sagittal Split Osteotomy on the Rate and Timing of Baseline Sensory Recovery.

PURPOSE: Neurosensory disturbance is the most common consequence of sagittal split osteotomy (SSO). The purpose of this study is to quantitatively assess neurosensory deficiency and recovery to the preoperative status when the inferior alveolar nerve (IAN) was exposed versus unexposed during SSO. METHODS: This is a single-center, prospective, cohort study of all patients undergoing bilateral SSO between August 2018 and July 2019. Patients were included in the study sample if they underwent bilateral SSO with an intact intraoperative IAN and were received follow-up assessment for at least a year. The predictor variable was the intraoperative IAN status (exposed vs unexposed). The outcomes of interest were the rate and timing of recovery to the preoperative status. The covariates were age, sex, and the magnitude and direction of surgical movements. Neurosensory function was quantitatively evaluated using the Semmes-Weinstein monofilament test at follow-up intervals of 1, 3, 6, and 12 months. Descriptive statistics, bivariate statistics, Cox proportional hazards regression, and Kaplan-Meier analyses were performed. P value <.05 was considered statistically significant. RESULTS: Of 90 patients, 86 patients who underwent 172 SSOs were included in this study. The mean age was 22.95 ± 3.34 years (range, 17 to 30), 65 were women, and the range of surgical movements was 3 to 8.3 mm of advancement and 2 to 12 mm of setback. Eighty-five nerves (49.4%) were allocated to the unexposed group, and 87 (50.6%) to the exposed group, with statistically significant differences in the rate and timing of recovery (hazard ratio = 2.368; 95% confidence interval, 1.662 to 3.376; P < .001). Among those with recovered nerves, the median time to recovery was 90 days in the unexposed group and 364 days in the exposed group (P < .0001). CONCLUSIONS: IAN exposure during SSO is associated with an increased risk of neurosensory deficiency and an increased time of sensory recovery to the baseline threshold in patients aged 17 to 30 years. When the IAN remained fully enclosed in the canal of the distal segment, only 11% of patients had a measurable sensory deficit 1 year after surgery. In those patients with any degree of IAN exposure, 36% had a residual sensory deficit 1 year after surgery.