Mandibular Movement Research Articles

Implementing an optical jaw tracking system to locate centric occlusion: A dental technique

Optical jaw tracking systems are designed to record the static maxillomandibular relationship and the mandibular motion of a patient, including excursive movements and mastication pattern. This digital data acquisition technology can be integrated into diagnostic and treatment planning procedures, as well as into designing dental prostheses. A step-by-step protocol to record a patient’s digital data, including the repeatable reference position of the jaw or centric relation, by using an intraoral scanner, Kois deprogrammer, and optical jaw tracking system is described. The data are then processed in the software program of the jaw tracking system to locate centric occlusion.

Fully digital workflow for the fabrication of occlusal stabilization splints based on individual mandibular movement

ObjectiveThis study was conducted to present a completely digital workflow for the fabrication of occlusal stabilization splints using CAD/CAM systems and a digital face bow based on optical sensor technology. MethodsDigital scans of the maxillary and mandibular arches of 20 volunteers were obtained using an intraoral scanner. Jaw relation and mandibular movements were recorded with a digital face bow via optical sensors. The virtual increase of the vertical dimension of occlusion (VDO) was then performed, after which computer-aided design (CAD) of the occlusal stabilization splints was carried out. The corresponding splints were then manufactured using digitally controlled technology. ResultsA completely digital workflow for the manufacturing of occlusal stabilization splints was found to be clinically feasible. The corresponding data analysis revealed high congruence between virtual and physical occlusal contacts on the occlusal splint. Moreover, the appropriate guidance of the anterior teeth area was easily obtainable, and the time for adjusting the occlusion was less. ConclusionsThis study demonstrated that the fabrication of occlusal stabilization splints using a fully digital workflow is feasible. Compared to traditional impression-based manufacturing, several advantages of digital manufacturing include easy accessibility, time-efficient manufacturing, high-level accuracy in splint quality, and potential to manufacture duplicate splints. Clinical significanceThe proposed fully digital approach may help young dentists fabricating stable occlusal splints with beneficial curative effects. Meanwhile, it could also improve the production efficiency of stable occlusal splints, saving time for both doctors and patients while reducing labor costs.

Comparison of three-dimensional soft tissue changes according to the split pattern after sagittal split osteotomy in patients with skeletal class III malocclusion

ObjectivesThis study aimed to analyse the changes in soft tissue and hard tissue stability associated with the split pattern, i.e. long split (LS) or short split (SS), after sagittal split osteotomy.Materials and methodsPatients who underwent sagittal split ramus osteotomy were classified into LS or SS groups according to postoperative computed tomography images. They were examined via lateral cephalography and three-dimensional (3D) optical scanning before surgery (T0) and 1 (T1), 3 (T2), and 12 (T3) months after surgery. Six standard angles (SNA, SNB, ANB, FMA, FMIA, and IMPA) were used as measures of hard tissue change. The two sets of 3D data were superimposed, and the volumetric differences were calculated as the soft tissue change. The areas evaluated were delimited by 10 × 20-mm rectangles in the frontal aspect and a 25 × 25-mm square in the lateral aspect.ResultsA total of 42 sides (26 patients) were analysed, including 20 (16 patients) in the SS group and 22 (16 patients) in the LS group. We found no significant differences in cephalographic angle or soft tissue changes in the frontal aspect between the SS and LS groups. We found significant differences in the subauricular region from T0–T1 (p = 0.02), T0–T2 (p = 0.03), and T0–T3 (p = 0.037) in terms of soft tissue changes in the lateral aspect. The volume increase associated with posterior mandibular movement was greater in the LS group.ConclusionsWe found that LS patients with mandibular prognathism exhibited increased subauricular volumes following mandibular setback.Clinical relevanceIt is essential to predict the postoperative facial profile before surgery. The split pattern after sagittal split osteotomy affects the postoperative profile of patients with mandibular prognathism.

Temporomandibular disorders, occlusal splints, and treatment options: a survey-based investigation

Background: The term "temporomandibular disorders" (TMDs) refers to a group of painful conditions that affect both the hard and soft orofacial anatomical structures. The primary objectives of TMD treatment are to lessen pain and enhance mandibular movements, re-establishing proper functioning. One of the widely used treatment options for TMDs pathology is the occlusal splint. This non-invasive intraoral device, determines both the muscle relaxation and reversibly repositions the temporomandibular joint structures. The study aimed to compare the efficacy of different occlusal splint designs or materials in managing TMD symptoms. Methods: Twenty-six patients, nineteen of whom were female and seven of whom were male, ranging in age from twenty to seventy, met the criteria needed participate in this study. Two different questionnaires were formulated: a patient-focused and a clinician-focused questionnaire. The patient's data encompassed general health status and TMD signs and symptoms, whereas the clinician's questions addressed assessment and treatment alternatives, including the particularities of occlusal splint therapy. Results: The majority of the patients were diagnosed with disc displacement with reduction (61.5%), followed by myalgia (26.9%). The only form of treatment preferred by physicians was the Michigan occlusal splint, which was mainly used on the maxillary dental arch (84,6%). After the splint therapy was completed and the intended results were obtained, the treatment plan was finished using selective grinding, prosthetic dental restorations, orthodontic therapy, or a combination of these procedures. The patient was required to continue physical therapy (7,7%), wear a full-arch night guard (42.3%), and undergo rigorous periodic control sessions (34.6%) to maintain the final aesthetic and functional results. Conclusions: Occlusal splints are an efficient and reliable initial therapy preference for patients with temporomandibular disorders. In addition to improving symptoms in the temporomandibular joint, occlusal splints may determine mandibular repositioning, which also implies a variety of treatment approaches, ranging from the minimally invasive to the most complex, to achieve a functional occlusal status.

Daphnia magna digestive activity is differentially altered when exposed to equally turbid waters caused by either suspended sediment or suspended microplastics.

Turbidity can be a result of suspended natural particles, such as sediment, or anthropogenic particles such as microplastics. This study assessed whether Daphnia magna, a pelagic filter feeder known to ingest suspended particles, have an altered response to equally turbid environments caused by the presence of either suspended bentonite or suspended polyethylene microplastics. Compared to controls, daphnids exposed to suspended bentonite maintained their feeding efficiency and increased their digestive activity, as measured by mandibular movement, peristalsis, and expulsion, to pass bentonite through the digestive tract. The same effects were not seen in microplastic-exposed individuals, in which feeding efficiency was decreased and only peristaltic movement was increased but without a coordinated increase in expulsion, suggesting that microplastics do not have the same ability as bentonite to pass through the digestive tract. This study highlights the need to discern the identities of particulates contributing to turbid environments as different particles, even of the same size, can have different effects on filter feeders, which inherently ingest suspended particles.

Management of hemi-mandibulectomy patient with prosthetic devices

The success in rehabilitating a patient with hemi-mandibulectomy depends upon the nature and extent of the surgical defect, treatment plan, type of prosthesis, and patient co-operation. The management becomes more challenging when the prosthetic reconstruction has been delayed. The scar tissue forms and the soft tissue becomes stiff, causing severe deviation in the mandible towards the resected side. This case report presents a58year old male patient who underwent a mandibular resection surgery after he was diagnosed with buccal mucosa carcinoma. The patient had mandibular deviation and deranged occlusion making his speech, mastication and esthetics compromised.: The patient was provided with a cast guide flange prosthesis in the beginning as a training device to prevent the scar contracture and increase the mandibular movement towards healthy side to increase the intercuspation. After few months of training, when the deviation was reduced, flexible maxillary and mandibular partial dentures were fabricated with double occlusion in the maxillary denture to increase the masticatory efficiency of the patient.This case report attempts to formulate a treatment plan whereby the patient's discomfort could be minimized. The treatment starts with the fabrication of a removable guide flange as a physical therapy device to reduce the mandibular deviation followed by provision of a maxillary denture with double occlusion to obtain maximum intercuspation.The mandibulectomy patient is difficult to manage because a prosthodontist is limited in his ability to provide a reasonable and practical prosthesis. However, if the patients recognize the limitations of their rehabilitation, they would be more appreciative of the prosthodontic therapy that enhances their rehabilitative progress.

Sleep bruxism and associated physiological events in children with obstructive sleep apnea: a polysomnographic study.

The aim of this study was to evaluate the physiological events associated with sleep bruxism (Sleep Bruxism [SB]; presence of mandibular movement activity) and the control window (4 minutes prior to SB event, where no mandibular movement activity was detected) in a polysomnography study in children with mild sleep apnea. Polysomnography data from children aged 4 to 9 years old diagnosed with mild sleep apnea were analyzed by 2 trained examiners. The mandibular movement activity (bruxism event; SB) was classified into phasic and tonic. The control window was selected 4 minutes prior to the SB event. All physiological events were recorded in both bruxism and control windows, including sleep phase (N1, N2, N3, and rapid eye movement), arousal, leg movements, tachycardia, bradycardia, oxygen desaturation, and number of obstructive and central sleep apnea events. The moment in which those phenomena occurred when associated with SB was also analyzed (before/after). Data were analyzed using 95% confidence intervals (α = 5%). A total of 661 mandibular movements were analyzed and classified as tonic (n = 372) or phasic (n = 289). The mean apnea-hypopnea index was 1.99 (SD = 1.27) events/h. The frequency of leg movements, microarousal, and tachycardia was increased in SB events when compared with the control window (P < .05). There was an increase in bradycardia frequency in the control window when compared with SB (in both tonic and phasic events). The frequency of obstructive and central apnea during SB was lower when compared with the other physiological phenomena. There is a difference in the physiological parameters evaluated in children with mild sleep apnea when comparing the 2 windows (SB and control). Sleep bruxism is associated with other physiological phenomena, such as leg movements, tachycardia, and microarousal. The use of a control window (where no mandibular activity was detected) was representative since it did not show activation of the sympathetic nervous system. Bonacina CF, Soster LMSFA, Bueno C, etal. Sleep bruxism and associated physiological events in children with obstructive sleep apnea: a polysomnographic study. J Clin Sleep Med. 2024;20(4):565-573.

Analysis of Mandibular Movement after insertion of Fixed Partial Dentures using Cadiax Compact II®

The aim of this clinical study was to analysis the mandibular movement in patients after insertion of fixed partial dentures using Cadiax Compact II and compares the Horizontal condylar angles and Bennette angles before and after insertion of posterior fixed partial denture.Material and methods: Mandibular movement of thirty two patients, sixteen males and sixteen female planed for posterior fixed partial dentures), had been recorded using Cadiax Compact II® for Horizontal Condylar Inclination and Bennette Angle. Three records had been obtained R1 before the abutments teeth preparations of the Fixed Partial Dentures, R2 after the cementation of the Fixed Partial Dentures and R3 after one month of the Fixed Partial Dentures cementation.Results: Statistical highly significant difference was found between R1&amp;R2 for Bennette angles in both males and females, and significant difference in group R1&amp;R3 for Horizontal condylar Inclination in females only. The other groups show no statistical significant difference.Conclusion: Within the limit of this clinical study, the insertion of fixed partial denture have no changing effect on the Horizontal Condylar inclination in males but in females have mild change. For Bennette angle there is highly significant change in both males and females immediately after the fixed partial denture cementation, but after one month this change disappeared.

Chewing Analysis by Means of Electromagnetic Articulography: Current Developments and New Possibilities

Chewing is a complex procedure that involves sensory feedback and motor impulses controlled by the trigeminal system in the brainstem. The analysis of mandibular movement is a first approximation to understanding these mechanisms. Several recording methods have been tested to achieve this. Video, ultrasound, the use of external markers and kinesiographs are examples of recording systems used in research. Electromagnetic articulography is an alternative method to those previously mentioned. It consists of the use of electromagnetic fields and receiver coils. The receiver coils are placed on the points of interest and the 3D coordinates of movement are saved in binary files. In the Oral Physiology Laboratory of the Dental Sciences Research Center (Centro de Investigación en Ciencias Odontológicas—CICO), in the Faculty of Dentistry at the Universidad de La Frontera (Temuco, Chile) several research studies have been carried out using the AG501 3D EMA articulograph (Carstens Medizinelektronik, Lenglern, Germany). With this device, they developed a series of protocols to record mandibular movement and obtain new information, such as the 3D Posselt polygon, the area of each polygon, individualized masticatory cycles and speed and acceleration profiles. Other investigations have analyzed these parameters, but separately. The AG501 allows for holistic analysis of all these data without altering natural movement. A limitation of this technology is the interference generated by its metallic elements. The aim of the present work is to show the developed methods used to record mandibular movement in the CICO, using the AG501 and compare them with others used in several research studies.

Condylar volume and positional changes following a bilateral sagittal split ramus osteotomy in skeletal class II and III malocclusions

BackgroundMandibular condyle remodeling and displacement are post-orthognathic surgery concerns that can potentially lead to occlusal issues after bilateral sagittal split ramus osteotomy. This retrospective study examined the relationship between condylar volume changes and position alterations after surgery in patients with skeletal class II and III malocclusions using cone-beam CT.MethodsThe study included 16 patients (6 with Class II malocclusion, 10 with Class III malocclusion) who underwent bilateral sagittal split ramus osteotomy at Chonnam National University Hospital. Cone-beam CT data were collected at three specific time points: before surgery, immediately after surgery, and approximately 6 months post-surgery. Mandibular movement was measured using InVivoDental 5.4.6. ITK-SNAP 3.8.0 was used to assessed condylar volume changes post-surgery. Condyle positions were evaluated in four parts with RadiAnt DICOM Viewer 4.6.9. Statistical analyses were performed using the SPSS version 23.ResultsConsidering both Class II and III malocclusion, a 2.91% volume reduction was noted immediately and at 6 months after surgery. Both Class II and III cases demonstrated a decrease in superior joint space by -0.59 mm and medial joint space by -1.09 mm. No significant correlation was found between this process and condylar volume change.ConclusionsThe mandibular condyle volume decreased, and superior-medial movement of the condyle was detected in patients with Class II and III malocclusion immediately and at 6 months after surgery with no volume-position correlation.

Comparative evaulation of condylar guidance obtained by digital panoramic radiographic images with that of obtained during jaw relation and try-in using two different interocclusal record material in completely edentulous patients: an in vivo study

Background: In completely edentulous patients, maintaining the patient's TMJ health and intraoral components is very important. This can be achieved by an accurate interocclusal record, which can we taken by various materials and also at various stages. Simulation of the temparomandibular joint anatomy and mandibular movements is possible on a semi adjustable articulator which is use widely in prosthodontics. Transferring the record on articulator is a critical step in fabrication of complete dentures so it should be done precisely to reduce chair side time and also to avoid complications for patients. This study examines which material is more accurate and also records which stage gives more precision, by comparing the Condylar guidance on radiographs. This is because it has consistent bony landmarks and is comparable to clinical methods in terms of standardisation. The objective will be to determine the inter occlusal records created during Jaw Relation stage and Try-in using reinforced wax and Polyvinyl siloxane and compare these values to the condylar guidance obtained by OPG. Methods: Recording the Condylar Guidance value on OPG, obtained with tracing Glenoid fossa, Articular eminence and the Frankfurt Horizontal Plane. Followed with conventional steps in making complete dentures, at jaw relation and try-in stage. we will record values of condylar guidance with the two different Interocclusal record materials. Expected result: It will help the clinicians to get knowledge about obtaining precise condylar inclination angle by using right interocclusal record materials. Conclusions: This study will help us to obtain condylar inclination which inturn helps the patients satisfaction as it maintains the patient's TMJ health and intraoral components.

Three-Dimensional Navigation-Assisted Open Reduction and Internal Fixation of a Subcondylar and Ramus Fracture on a Maxillary Oligodontia Patient.

Treatment of condylar fractures in patients with edentulous mandibles or no-occlusion reference is particularly challenging due to the absence of important anatomical structures and landmark for occlusion analysis. In this case, a 69-year-old female maxillary oligodontia victim suffered from a traumatic accident with a right facial contusion, resulting in a right-side subcondylar and mandibular ramus fracture with right ramus height loss. In the preoperative planning, the 3-dimensionalimage of the left-side mandible was highlighted by the navigation software. A mirror image of the left-side mandible was made and superimposed on the right side of the face. Surgical intervention with an endoscope and 3-dimensional navigation-assisted open reduction and internal fixation of the right-side subcondylar and ramus fracture was performed. The patient recovered well with no restriction in mandibular movement, no limitation in mouth opening, and a satisfied esthetic outcome.

A clinical comparison of sagittal condylar inclination and Bennett angle derived from a conventional electronic tracking device and an optical jaw tracking device

The challenges of conventional methods to measure the sagittal condylar inclination and the Bennett angle include patient discomfort and an output of averaged values calculated on the arc of mandibular movement. Programming these average values into a mechanical or mathematically simulated articulator may introduce occlusal errors. The purpose of this clinical study was to compare the sagittal condylar inclination and Bennett angle measurements derived from a conventional electronic tracking device and an optical tracking device. Fifteen dentate participants with at least 12 occluding units, 25 years old and above, participated in the study. Each participant's mandibular movements were recorded by the 2 systems for different condylar guidance values. A conventional tracking device, the Cadiax Compact 2, and an optical tracking device, the MODJAW, were used for this study. Sagittal condylar inclination was measured at 3mm and 5mm using protrusive records and the values of the Bennett angle at 3mm were measured using excursive records along the path traced by mandibular condyles. The Wilcoxon signed-rank test was used to analyze the paired data from the 2 methods. A significant difference was found between right (P=.007) and left sagittal condylar inclinations (P=.010) measured at 3mm with the conventional and optical tracking devices. A significant difference was found between right (P=.015) and left sagittal condylar inclinations (P=.004) measured at 5mm with the conventional and optical tracking devices. The right and left Bennett angles measured at 3mm with the conventional and optical tracking devices were statistically different (P=.043 and P=.035 respectively). The sagittal condylar inclination and Bennett angle measured at different positions along the path of movement exhibited significant differences. The sagittal condylar inclination and Bennett angle values obtained from the conventional tracking device were generally significantly less than those derived from the optical tracking device.

Bilateral fibro-osseous TMJ ankylosis in Marie-Strumpell disease: a case report

Reporting a case of bilateral fibro-osseous TMJ ankylosis in Marie-Strumpell disease. Managed with interposition gap arthroplasty with temporalis myofacial flap. Marie-Strumpell disease or ankylosing spondylitis is a chronic inflammatory disorder affecting predominantly the axial skeleton although peripheral joint involvement may be a significant feature. Temporo-mandibular joint involvement in ankylosing spondylitis varies from 4% to 35%. A 53-year-old male patient reported to our department with a chief complaint of difficulty in opening his mouth and difficulty in eating food. The case was diagnosed as a case of bilateral fibro-osseous TMJ ankylosis associated with ankylosing spondylitis. The individual was managed with aggressive resection of ankylotic segments and inter-position of the temporalis myofascial flap bilaterally with early mobilization and aggressive physiotherapy. Aggressive resection of the ankylotic mass with inter-positional gap arthroplasty with early mobilization and aggressive physiotherapy is a highly effective and safe surgical management option for the management of TMJ ankylosis and with acceptable immediate and long-term outcome with minimum re-ankylosis and have produced satisfactory mandibular movements.

The efficacy of combining low-level laser therapy with oral motor exercises in patients with temporomandibular disorders (pilot study)

Background: The term temporomandibular disorders (TMDs) is used for clinical signs and symptoms affecting the masticatory muscles, temporomandibular joints (TMJs) and associated structures or both. TMDs may present clinically with facial pain in the region of the TMJs and/or muscles of mastication, limitation in mouth opening, and TMJ clicking during mastication. Treatment of TMDs includes occlusal splints, drug therapy, physiotherapy, auriculotherapy and low-level laser therapy (LLLT). Methods: Ten patients with TMD were recruited from the Oral Medicine clinics at Prince Sultan Military Medical City. The participants were randomly allocated into two equal groups. All participants attended a total of eight laser treatment sessions using a 940 nm diode laser. The deep-tissue laser hand-piece was applied perpendicular to the Temporalis muscle, Masseter muscle and TMJ region bilaterally. Patients in the second group attended physiotherapy sessions in addition to the laser sessions. Participants were evaluated for range of mandibular movement, pain, and tenderness to palpation before treatment, one-week post-treatment, and thirty days after treatment completion. Results: This study, being a pilot study, was conducted in a comparatively small number of patients. It allowed for the assessment of research feasibility, methodology, limitations, and preliminary outcomes. Moreover, variations in the response to treatment were observed between the two groups, with results of this study supporting previous findings that LLLT is an effective treatment for TMD symptoms, tenderness to palpation, as well as improving jaw functional behavior. Conclusions: Therefore, LLLT therapy may be a promising tool for the management of TMD, especially when combined with physiotherapy.

Mandibular lateral incisor-first premolar transposition in early mixed dentition: a rare case.

Dental transposition is an anomaly of eruption which is usually seen in the maxilla and rarely in the mandible. The mandibular lateral incisor's transposition with the permanent canine has a prevalence of less than 0.03%. The following case presents an even rarer situation, of a right lateral mandibular incisor that erupted in the place of the first premolar, in transposition with the temporary canine. In the first phase, a series of extractions have been performed, to ensure the necessary free space for moving the lateral incisor closer to its appropriate place, and after that a fixed orthodontic appliance was used. The biomechanics for intra-arch tooth movement was ingenious enough to ensure a perfect alignment of all permanent teeth and a functional Class I canine and molar final occlusion. Early intervention and successful move of the permanent canine in its correct position ensured the functionality of the mandibular movements and a good long-term prognosis.

Considerations for the Use of Alloplastic Temporomandibular Joint Replacement in Irradiated Patients: Report of an Off-Label Indication.

Custom-made alloplastic temporomandibular joint replacement (ATMJR) is not validated in irradiated patients. However, in specific situations, after previous reconstructive surgical failures, the authors hypothesized the role of a customized ATMJR after radiotherapy. A 65-year-old male patient was referred to Instituto Português da Face-Lisbon, Portugal-after failed attempts of mandibular reconstruction secondary to oral carcinoma resection and partial hemi-mandibulectomy plus radiotherapy of 60 total Grays. Primary reconstruction was performed with fibula free flap. Due to failure, secondary reconstructions were performed with osteosynthesis plate without success. The patient was unable to have adequate mastication and deglutition due to a severe crossbite. The authors treated the patient with an extended customized alloplastic temporomandibular joint replacement (F0M2). With 3 years of follow-up, the patient showed an improvement in masticatory function, mandibular motion, pain levels, and overall quality of life. No complications were observed related to ATMJR. The presented case described how ATMJR, although not a validated option after radiotherapy, can be considered to restore functionality in complex cases with bone and soft tissues problems.

Characterization of labiomandibular movements induced after isolated LeFort I osteotomy in the surgical management of class III malocclusion.

Maxillary surgery alone can be proposed for the surgical management of class III malocclusion, but anticipating outcomes for the labiomental muscle complex is challenging due to the mandibular autorotation phenomenon. The objective of this study was to quantify the mandibular and labiomental movements induced by maxillary osteotomy alone in the management of class III malocclusion according to different clinical and surgical variables. The post-operative changes in mandibular and labiomental shapes were studied by geometric morphometry from the pre- and post-operative lateral cephalometric radiograph of 25 patients. The explanatory variables tested were maxillary advancement, maxillary rotation, and divergence. Soft tissues repositioning are different from postoperative mandibular repositioning after maxillary osteotomy. Neuromuscular adjustments of mandible depend on divergence and the maxillary rotation. Labiomental response only depends on divergence. The surgical procedure does not have the same bone-related and musculocutaneous effects on patients with the same class III malocclusion. It is therefore essential for surgeons to understand the effects of their procedure on musculocutaneous tissues in order to best anticipate post-operative outcomes.

The effect of photobiomodulation auriculotherapy in the treatment of temporomandibular disorders: A double-blind randomized feasibility study

IntroductionTemporomandibular disorders (TMD) are considered the most common complaint associaetd with orofacial pain. A treatment approach for TMD is photobiomodulation auriculotherapy, however, a method that which still requires studies mainly with pulsed frequency. ObjectiveTo evaluate the feasibility of conducting a randomized clinical trial using pulsed frequency photobiomodulation auriculotherapy and determine the relevant sample size. MethodsThe study was a controlled randomized pilot study. Twenty one volunteers with TMD were randomized into experimental and placebo groups. The evaluation periods were pre-intervention and again after four weeks. The instruments used for the assessment were axis I (mandibular movement measurements [MMM]) and axis II (Graded Chronic Pain Scale [GCPS], Jaw Functional Limitation Scale [JFLS-8], The Patient Health Questionnaire [PHQ-4], and Generalized Anxiety Disorder [GAD-7]) from Diagnostic Criteria for Temporomandibular Disorders (DC/TMD). Mann–Whitney and Wilcoxon tests were used for comparison of groups. The intervention protocol was performed once a week for foour weeks. ResultsThe GCPS question about “pain at this exact moment” indicated lower values for the treated group compared to the placebo group (U = 15.50; p = 0.005) after the intervention. The calculation of the total sample was 22 volunteers. The JFLS-8 variable showed no difference between the groups and the sample calculation ranged from 39 to 281 volunteers. The MMM showed no difference between the groups, and the calculation of the necessary sample ranged from 27 to 2.317. The variable PHQ-4 (U = 21.00; p = 0.02) and GAD-7 (U = 20.00; p = 0.02) showed differences between groups with type I error. The required sample was 22 volunteers for PHQ-4 and 25 for GAD-7. ConclusionWe conclude that this study is feasible and that the required sample should be 11 volunteers for each group in the GCPS subitem “pain intensity at this exact moment”. We were able to find results for this GCPS subitem. However, for other variables we need 25 volunteers for GAD7 and 22 volunteers for PHQ-4. Other variables, such as JFLS-8 and MMM, made it impossible to conduct these scales for future studies.

Risk factors for postoperative infection after bilateral sagittal split ramus osteotomy: A retrospective analysis

BackgroundThis retrospective clinical study investigated risk factors for infection following bilateral sagittal split ramus osteotomy (BSSO) as orthognathic surgery, including the patients' general condition, local factors, and surgical factors. Patients and methodsThe cases of 160 mandibular sites of 80 Japanese patients (26 males, 54 females; mean ± SD age: 25.3 ± 7.7 years, range 16–55 yrs) with a jaw deformity who underwent BSSO orthognathic surgery at our Department of Oral and Maxillofacial Surgery between Jan. 2017 and Dec. 2022 were analyzed. Potential risk factors were classified as clinical predictive variables. Descriptive and univariate statistics were computed. A multivariate analysis was performed with logistic regression. ResultsFifteen mandibular sites (9.4 %) were complicated with postoperative infection. The multivariate analysis revealed significant differences in facial asymmetry (OR 24.0, p = 0.0002) and the amount of mandibular movement (OR 0.664, p = 0.011) between the sites with and without infection. ConclusionsAmong clinical variables, facial asymmetry was the strongest risk factor for post-BSSO infection, followed by the amount of mandibular movement.