Microbiome of periodontitis and peri-implantitis before and after therapy: Long-read 16S rRNA gene amplicon sequencing.

AIMS: The microbial profiles of peri-implantitis and periodontitis (PT) are inconclusive. The controversies mainly arise from the differences in sampling sites, targeted gene fragment, and microbiome analysis techniques. The objective of this study was to explore the microbiomes of peri-implantitis (PI), control implants (CI), PT and control teeth (CT), and the microbial change of PI after nonsurgical treatment (PIAT). METHODS: Twenty-two patients diagnosed with both PT and peri-implantitis were recruited. Clinical periodontal parameters and radiographic bone levels were recorded. In each patient, the subgingival and submucosal plaque samples were collected from sites with PI, CI, PT, CT, and PIAT. Microbiome diversity was analyzed by high-throughput amplicon sequencing using full-length of 16S rRNA gene by next generation sequencing. RESULTS: The 16S rRNA gene sequencing analysis revealed 512 OTUs in oral microbiome and 377 OTUs reached strain levels. The PI and PT groups possessed their own unique core microbiome. Treponema denticola was predominant in PI with probing depth of 8-10 mm. Interestingly, Thermovirga lienii DSM 17291 and Dialister invisus DSM 15470 were found to associate with PI. Nonsurgical treatment for peri-implantitis did not significantly alter the microbiome, except Rothia aeria. CONCLUSION: Our study suggests Treponemas species may play a pivotal role in peri-implantitis. Nonsurgical treatment did not exert a major influence on the peri-implantitis microbiome in short-term follow-up. PT and peri-implantitis possess the unique microbiome profiles, and different therapeutic strategies may be suggested in the future.

Prosthetic Rehabilitation After Transfemoral Amputation in a Patient With an Ipsilateral Girdlestone Hip: A Case Report.

To date, there have been no reported cases of patients walking with a prosthesis after receiving an ipsilateral transfemoral amputation following the Girdlestone procedure. We administered a four-month prosthetic rehabilitation program to a 66-year-old man after his transfemoral amputation following the Girdlestone procedure. As a result, he was able to walk using the prosthesis for his daily activities. The prosthesis socket featured a quadrilateral configuration. The patient's ability to ambulate after the Girdlestone procedure was attributed to his ischial tuberosity serving as the primary load-bearing site in the transfemoral prosthesis. With appropriate prosthetic design, fabrication, and rehabilitation, patients can walk using a transfemoral prosthesis even in cases of transfemoral amputation following the Girdlestone procedure.

Enhancement of in vitro antibacterial activity and bioactivity of iodine-loaded titanium by micro-scale regulation using mixed-acid treatment.

Postoperative infection and subsequent device loss are serious complications in the use of titanium dental implants and plates for jawbone reconstruction. We have previously reported that NaOH-CaCl2 -thermal-ICl3 -treated titanium (NaCaThIo) has a nano-scale surface and exhibits antibacterial activity against Staphylococcus aureus. The present study examined the surface properties of mixed-acid treated and then iodine-treated titanium (MA-NaCaThIo), and evaluated oral antibacterial activity and cytotoxicity compared with the results obtained with NaCaThIo. MA-NaCaThIo formed a surface layer with a nano-scale network structure having microscale irregularities, and both the thickness of the surface layer (1.49 ± 0.16 µm) and the average surface roughness (0.35 ± 0.03 µm) were significantly higher than those of NaCaThIo. Furthermore, MA-NaCaThIo maintained high hydrophilicity with a contact angle of 7.5 ± 1.7° even after 4 weeks, as well as improved apatite formation, iodine ion release, and antibacterial activity against Prevotella intermedia compared to NaCaThIo. Cell culture test revealed that MA-NaCaThIo exhibited no cytotoxicity against MG-63 and Vero cells, while increased cell proliferation, ALP activity and mineralization of MG-63 compared to NaCaThIo. This treated titanium is expected to be useful for the development of next-generation titanium devices having both bone-bonding and antibacterial properties.

Clinical Study of 14 Cases of Bone Augmentation with Selective Laser Melting Titanium Mesh Plates.

Additive manufacturing techniques are being used in the medical field. Orthopedic hip prostheses and denture bases are designed and fabricated based on the patient's computer-aided design (CAD) data. We attempted to incorporate this technique into dental implant bone augmentation. Surgical simulation was performed using patient data. Fourteen patients underwent bone augmentation using a selective laser melting (SLM) titanium mesh plate. The results showed no evidence of infection in any of the 14 patients. In 12 patients, only one fixation screw was used, and good results were obtained. The SLM titanium mesh plate was good adaptation in all cases, with bone occupancy greater than 90%. The average bone resorption of the marginal alveolar bone from the time of dental implant placement to the time of the superstructure placement was 0.69 ± 0.25 mm. Implant superstructures were placed in all cases, and bone augmentation with SLM titanium mesh plates was considered a useful technique.

Prosthetic Rehabilitation of a Female With Bilateral Transfemoral Amputation in Japan: A Case Report.

Individuals with bilateral transfemoral (TF) amputation experience difficulties when walking with lower limb prostheses. Walking with prostheses is even more difficult when the cause of the amputation is nontraumatic, or the gender is female. We provided prosthetic rehabilitation to a woman who underwent bilateral TF amputation due to internal disease.  A 42-year-old woman underwent bilateral TF amputation for ischemic necrosis of the lower extremities during septic shock treatment. Upon admission to our convalescent rehabilitation ward 3 months after surgery, the patient weighed 32 kg and was underweight. After admission, she underwent strength training of the trunk and hip muscles, hip joint range of motion exercises, and bottom shuffle exercises on the physical therapy table. The prosthetist created stubby prostheses for standing and standing-up exercises on the floor, as well as gait exercises. We gradually extended the length of her prostheses and subsequently switched her knee joints to Ottobock locking and polycentric knees and eventually to Kenevo, which are microprocessor-controlled prosthetic knees (MPK). During occupational sessions, she practiced household activities such as washing dishes, cleaning, and cooking while wearing her prostheses. Six months after admission, the patient was discharged and could walk outdoors alone with two canes without using a wheelchair. At discharge, the Kenevo modes were Mode C on the right and Mode B + on the left. The patient's weight recovered to 41 kg. The patient completed the 10-meter walk test at 0.50 m/s at a comfortable walking speed, the 6-minute walk test at 180 meters, and the timed up and go (TUG) test in 26 seconds. The motor Functional Independence Measure (FIM) score was improved from 60 on admission to 83 on discharge.  Strengthening the hip and trunk muscles, improving endurance and balance, preventing hip contracture, and maintaining the hip range of motion are necessary for walking with bilateral TF prostheses. In the prosthetic rehabilitation of bilateral TF amputations, stubby prostheses, protocols for gradual extension of the prosthetic length, and Kenevo, a mode-changeable MPK, are helpful. MPK is essential for individuals with bilateral TF amputations to walk independently and use their prostheses daily. This report is a valuable reference for healthcare professionals involved with bilateral TF amputees in the future who need prosthetic rehabilitation.

Changes in salivary microbiota due to gastric cancer resection and its relation to gastric fluid microbiota.

Gastric cancer is one of the leading causes of death worldwide, and resections are performed to cure the disease. We have previously reported the changes in the gastric microbiota after gastric cancer resection, which may be associated with the oral microbiota; however, the changes in the oral microbiota remain uncharacterized. This study aimed to characterize the changes in the salivary microbiota caused by gastric cancer resection and to evaluate their association with the gastric fluid microbiota. Saliva and gastric fluid samples were collected from 63 patients who underwent gastrectomy before and after surgery, and a 16S rRNA metagenomic analysis was performed to compare the microbiota composition. The number of bacterial species in the salivary microbiota decreased, and the bacterial composition changed after the resection of gastric cancer. In addition, we identified several bacterial genera that varied significantly in the salivary microbiota, some of which also showed similar changes in the gastric fluid microbiota. These findings indicate that changes in the gastric environment affect the oral microbiota, emphasizing the close association between the oral and gastric fluid microbiota. Our study signifies the importance of focusing on the oral microbiota in the perioperative period of gastrectomy in patients with gastric cancer.

Results of Neuropathy Screening Test for Lower Limb Amputees With Diabetes Mellitus and Their Prosthetic Rehabilitation: A Cross-Sectional Study.

Introduction To prevent foot ulcers and subsequent amputation on the non-amputated side, we conducted tests for diabetic neuropathy. The results were then used in prosthetic rehabilitation for lower limb amputees with diabetes mellitus. Materials and methods This cross-sectional retrospective study included patients admitted to our convalescent rehabilitation ward for prosthetic rehabilitation between April 2019 and December 2022 following lower limb amputation due to diabetes. We investigated the positive rate of the modified Ipswich Touch Test (mIpTT) in lower limb amputees with diabetes, and physical and orthotic therapy and prosthetic rehabilitation based on medical records. Results Twenty-seven transtibial amputees and nine transfemoral amputees had diabetes. The mIpTT results were positive in 22 (81%) transtibial and eight (89%) transfemoral amputees. There were no apparent differences in positivity rates by amputation level, gender, or age. Based on these results, personalized physical therapy and insoles were prescribed for the non-amputee foot in parallel with prosthetic rehabilitation. Conclusions Lower limb amputees with diabetes have diabetic neuropathy more frequently than diabetic patients without amputation. As a result, they may also be at a higher risk of developing foot ulcers and subsequent amputation due to neuropathy. Therefore, rehabilitation to prevent amputation on the non-amputated side of lower limb amputees with diabetes had better encompassing foot exercises and orthotic therapy on the non-amputated side during the prosthetic rehabilitation period.

Bone Shortening After Amputation: A Report of Two Cases.

We report two cases of shortening of the bone at the stump after amputation. Case 1 was a 57-year-old male with a traumatic transhumeral amputation. The remaining humerus had shortened by 3.5 cm in eight months. Case 2 was a 27-year-old male with a traumatic transtibial amputation. The remaining tibia had shortened by 1.4 cm in 72 months. These two cases had the same cause of amputation, but the amputation site, age, and time course differed. Few studies have examined the bone length of stumps after amputation. The bone length of stumps is generally assumed to not change after amputation. However, the residual bone at the stump can shorten after amputation.

Determination of protamine and heparin based on their effects on a glucose oxidase enzymatic reaction.

This paper describes a sensitive method for determining protamine and heparin by utilizing a glucose oxidase enzymatic reaction. Polycationic protamine significantly promoted the enzymatic reaction rate with [Fe(CN)6]3-, so that the increase could be used to determine protamine. The promotion effect was stoichiometrically decreased by the addition of polyanionic heparin through the polyion complex formation with protamine, so that the enzymatic reaction also allowed for the determination of heparin. We thus applied the proposed method to blood plasma containing heparin and found that heparin did not stoichiometrically form a polyion complex with protamine, likely due to strong interactions between heparin and some components of the plasma. The proposed method allowed for the detection of free protamine (and/or weakly binding protamine with heparin) existing in the condition that protamine did not neutralize all of the heparin in the plasma. The method also permitted for the estimation of heparin concentrations using calibration curves. Thus, the proposed method would help reduce the risks of protamine overdose in heparin neutralization and would be a helpful tool in clinical practices that use heparin and protamine.

Characterization of Oral Microbiota Following Chemotherapy in Patients With Hematopoietic Malignancies.

Oral microbiota may be associated with serious local or systemic medical conditions resulting from chemotherapy. This study was conducted to evaluate the changes in the oral microbiota following the initiation of chemotherapy in patients with hematopoietic malignancies and to identify the characteristics of the oral microbiota associated with oral mucositis. Oral samples were collected from 57 patients with hematopoietic malignancies at 2 time points: before the start of chemotherapy and 8 to 20 days after the start of chemotherapy, when chemotherapy-induced oral mucositis often occurs, and 16S rRNA metagenomic analyses were performed. Comparative and linear discriminant analysis effect size (LEfSe) analyses were used to determine the characteristic bacterial groups before and after the initiation of chemotherapy and in those who developed oral mucositis. The alpha and beta diversities of oral microbiota before and after the initiation of chemotherapy differed significantly (operational taxonomic unit index, P < .001; Shannon's index, P < .001; unweighted UniFrac distances, P = .001; and weighted UniFrac distances, P = .001). The LEfSe analysis revealed a group of bacteria whose abundance differed significantly before and after the initiation of chemotherapy. In the group of patients who developed oral mucositis, a characteristic group of bacteria was identified before the start of chemotherapy. In conclusion, we characterized the oral microbiota associated with the initiation of chemotherapy in patients with hematopoietic malignancies. In addition, our findings suggest that oral microbiota composition before the start of chemotherapy may be associated with oral mucositis. The results of this study emphasize the importance of oral management focusing on the oral microbiota during chemotherapy in patients with hematologic malignancies.

Effect of high-intensity interval walking on microvascular endothelial function among community-dwelling older people.

AIM: To investigate the effects of high-intensity interval exercise training on microvascular endothelial function among community-dwelling older people. METHODS: We analyzed the data from a nonrandomized controlled trial. This study's participants were 48 men (aged 75 ± 5 years; exercise training group, n = 24; control group, n = 24) and 83 women (aged 75 ± 4 years; exercise training group, n = 36; control group, n = 47). The exercise training group underwent a high-intensity interval walking training for 5 months. RESULTS: In the exercise group, 100% and 91.7% of men and women, respectively, achieved brisk walking times ≥50 min/week. The change in the reactive hyperemia index significantly differed between the groups of men, whereas that in the control group was not significant; however, a significant increase was observed in the exercise training group. Among women, changes in the reactive hyperemia index were not significant in either group; however, for women in the exercise training group, these changes negatively and positively correlated with the change in body mass index (Spearman's rho = -0.342; P = 0.041) and baseline body mass index (rho = 0.362, P = 0.030), respectively. Additionally, the distribution of body mass index was broader in women than in men. CONCLUSIONS: Interval walking training increased the reactive hyperemia index in men rather than in women. A higher variation in baseline body mass index may be associated with no statistical increase in reactive hyperemia index in women. Geriatr Gerontol Int 2023; 23: 103-110.

Salivary Microbiota Associated with Peripheral Microvascular Endothelial Dysfunction.

AIMS: Oral health is associated with atherosclerotic cardiovascular disease (ACVD). We previously identified the salivary microbiota characteristics of patients with ACVD. However, whether salivary microbiota is characteristic under impaired vascular endothelial function before ACVD onset remains unclear. Therefore, we aimed to evaluate the characteristics of salivary microbiota associated with peripheral microvascular endothelial dysfunction. METHODS: We collected saliva samples from 172 community-dwelling elderly individuals without a history of ACVD and performed 16S rRNA metagenomic analysis. We assessed the peripheral microvascular endothelial function using reactive hyperemia index (RHI) and compared the salivary microbiota in the groups with normal (RHI ≥ 2.10), borderline, and abnormal (RHI ＜1.67) peripheral endothelial function. Furthermore, we applied machine learning techniques to evaluate whether salivary microbiota could discriminate between individuals with normal and abnormal endothelial function. RESULTS: The number of operational taxonomic units (OTUs) was higher in the abnormal group than in the normal group (p=0.037), and differences were found in the overall salivary microbiota structure (unweighted UniFrac distances, p=0.038). The linear discriminant analysis (LDA) effect size (LEfSe) algorithm revealed several significantly differentially abundant bacterial genera between the two groups. An Extra Trees classifier model was built to discriminate between groups with normal and abnormal vascular endothelial function based on the microbial composition at the genus level (AUC=0.810). CONCLUSIONS: The salivary microbiota in individuals with endothelial dysfunction was distinct from that in individuals with normal endothelial function, indicating that the salivary microbiota may be related to endothelial function.

Application of the Homologous Modeling Technique for Precision Medicine in the Field of Oral and Maxillofacial Surgery.

In the field of oral and maxillofacial surgery, establishment of a new method for predicting morphology is desirable. Therefore, the purpose of the present study was to establish a new method for predicting the original shape of a mandibular defect site using the homologous modeling technique. This study used data from 44 patients who underwent computed tomography in the Department of Oral Surgery at Osaka Medical College. Two types of homologous models were constructed: total mandible (TM) and half mandible (HM). Principal component analysis (PCA) was performed using point cloud data of the homologous model M and homologous model HM, and a multiple regression equation was created using the PC value of TM as the object variable and PC value of HM as the explanatory variable. The predicted PC (M) was created from PC (HM) using a regression formula, back-calculated from point cloud data from PC (M), to create the predicted mandible model. Finally, the original image (TC-M) and estimated mandible were superposed and examined. The mean absolute error between the predicted mandible and actual mandible was 1.04 ± 1.35 mm. We believe that this method will be applicable in actual clinical practice.

Determination of polyanion utilizing a promoted glucose oxidase enzymatic reaction by ε-poly-L-lysine.

In this paper, a sensitive determination method for polyanion using a glucose oxidase (GOx) enzymatic reaction with ferricyanide ion is described. We previously reported that the GOx enzymatic reaction was significantly promoted by a cationic polymer of ε-poly-L-lysine (εPL), and the enzymatic reaction could be utilized for the determination of εPL. Generally, polycation stoichiometrically forms polyion complex with polyanion. Thus, it is expected that the promotion effect of εPL on the enzymatic reaction is interfered by polyanion, and the enzymatic reaction is also applicable to the determination of polyanion. Predictably, the promotion effect of εPL was stoichiometrically interfered by polyanions, such as polyvinyl sulfate and polyacrylate, and the interference effect allowed for the determination of the polyanions. The detection limit of polyanion was estimated to be ~ 0.3 µeq L-1. As a preliminary application, the proposed method was applied to the determination of anionic polymer of heparin in a human plasma.

Comparison of the gastric microbiome in Billroth I and Roux-en-Y reconstructions after distal gastrectomy.

The changes in gastric microbiota following reconstruction after gastrectomy have not been reported. This study aimed to compare the gastric microbiota following Billroth I and Roux-en-Y reconstructions after distal gastrectomy. We enrolled 71 gastrectomized patients with gastric cancer; 31 and 40 underwent Billroth I and Roux-en-Y reconstructions, respectively. During upper gastrointestinal endoscopy, gastric fluid was collected immediately before and 6 months after distal gastrectomy. Deoxyribonucleic acid isolated from each sample was evaluated using 16S ribosomal ribonucleic acid metagenomic analysis. Analysis revealed that the gastric microbiota's species richness (expressed as the alpha diversity) was significantly lower after than before distal gastrectomy (operational taxonomic units, p = 0.001; Shannon index, p = 0.03). The interindividual diversity (beta diversity) was significantly different before and after distal gastrectomy (unweighted UniFrac distances, p = 0.04; weighted UniFrac distances, p = 0.001; Bray-Curtis, p = 0.001). Alpha and beta diversity were not significantly different between Billroth I and Roux-en-Y reconstructions (observed operational taxonomic units, p = 0.58; Shannon index, p = 0.95; unweighted UniFrac distances, p = 0.65; weighted UniFrac distances, p = 0.67; Bray-Curtis, p = 0.63). Our study demonstrated significant differences in gastric microbiota diversity, composition, and community before and after distal gastrectomy but no difference between Billroth I and Roux-en-Y reconstruction after distal gastrectomy.

Topical Xerostomia Treatment with Hyaluronate Sheets Containing Pilocarpine.

Sjogren's syndrome and radiation therapy for head and neck cancers are often accompanied by xerostomia. Oral pilocarpine (PCP) to treat xerostomia produces systemic side effects, such as runny nose and lacrimation. To improve the therapeutic efficacy of PCP and reduce the aforementioned side effects, we developed a topical delivery system for PCP using freeze-dried sheets of hyaluronic acid (HA). The advantages of HA sheets over conventional oral formulations were examined through in vivo pharmacokinetic and pharmacodynamic studies after their application to oral tissues and salivary glands. The concentration of PCP in the submucosal tissue of the oral cavity was determined using the microdialysis (MD) method after buccal application of HA sheets containing PCP to hamsters. The concentration of PCP in the MD outflow was quite low after gastric administration, whereas the PCP concentration in plasma was high. In contrast, after buccal application of HA sheets containing PCP, the concentration of the drug in the MD outflow increased, despite the negligible concentration in plasma. These findings indicated that both enhancement of saliva secretion and the avoidance of systemic side effects could be achieved through buccal administration of PCP-loaded HA sheets. In addition, the pharmacodynamic study showed that when compared with intravenous and gastric administration, salivary application of HA sheets containing PCP resulted in similar volumes of saliva secretion and reduced lacrimal secretions. In conclusion, freeze-dried HA sheets allow for the development of a novel buccal delivery system with enhanced therapeutic efficacy and safety to treat xerostomia.

Characterization of Salivary Microbiota in Patients with Atherosclerotic Cardiovascular Disease: A Case-Control Study.

AIMS: Oral bacteria have been reported to be associated with the pathogenesis of atherosclerosis; however, the relationship between the oral microbiota and atherosclerosis remains unclear. The present study aimed to investigate whether or not salivary microbiota of patients with atherosclerotic cardiovascular disease (ACVD) differs from that of subjects without ACVD, and to characterize the salivary microbiota of patients with ACVD. METHODS: This study included 43 patients with ACVD and 86 age- and sex-matched non-ACVD individuals. 16S rRNA metagenomic analysis were performed using DNA isolated from the saliva samples of the participants. To select unique operational taxonomic unit (OTU) sets of ACVD, we conducted the random forest algorithm in machine learning, followed by confirmation via 10-fold cross-validation Results: There was no difference in richness or evenness between the ACVD and non-ACVD groups (alpha diversity; observed OTU index, p=0.503; Shannon's index, p=0.478). However, significant differences were found in the overall salivary microbiota structure (beta diversity; unweighted UniFrac distances, p=0.001; weighted UniFrac distances, p=0.001). The Actinobacteria phylum was highly abundant in patients with ACVD, while the Bacteroidetes phylum was less abundant. The random forest classifier identified 43 OTUs as an optimal marker set of ACVD. In a 10-fold cross validation using the validation data, an area under the curve (AUC) of 0.933 (95% CI, 0.855-1.000) was obtained. CONCLUSIONS: The salivary microbiota in patients with ACVD was distinct from that of non-ACVD individuals, indicating that the salivary microbiota may be related to ACVD.

The effect of simple heat treatment on apatite formation on grit-blasted/acid-etched dental Ti implants already in clinical use.

Grit-blasted/acid-etched titanium dental implants have a moderately roughened surface that is suitable for cell adhesion and exhibits faster osseointegration. However, the roughened surface does not always maintain stable fixation over a long period. In this study, a simple heat treatment at 600°C was performed on a commercially available dental Ti implant with grit-blasting/acid-etching, and its effect on mineralization capacity was assessed by examining apatite formation in a simulated body fluid (SBF). The as-purchased implant displayed a moderately roughened surface at the micrometer scale. Its surface was composed of titanium hydride accompanied by a small amount of alumina particles derived from the grit-blasting. Heat treatment transformed the titanium hydride into rutile without evidently changing the surface morphology. The immersion in SBF revealed that apatite formed on the heated implant at 7 days. Furthermore, apatite formed on the Ti rod surface within 1 day when the metal was subjected to acid and heat treatment without blasting. These indicate that apatite formation was conferred on the commercially available dental implant by simple heat treatment, although its induction period was slightly affected by alumina particles remaining on the implant surface. The heat-treated implant should achieve stronger and more stable bone bonding due to its apatite formation.

Characterization of salivary microbiota in elderly patients with type 2 diabetes mellitus: a matched case-control study.

OBJECTIVE: The importance of oral health in type 2 diabetes mellitus (T2DM) is widely recognized; however, oral microbiota characteristics associated with T2DM in the elderly population are not well-understood. This study was conducted to evaluate the characteristics of the salivary microbiota in elderly Japanese patients with T2DM. METHODS: Saliva samples were collected from 42 elderly Japanese patients with T2DM and 42 age- and sex-matched subjects without T2DM (control). 16S ribosomal RNA metagenomic analysis and comparative analysis of both groups were performed. Random forest classification by machine learning was performed to discriminate between the salivary microbiota in the two groups. RESULTS: There were significant differences in the overall salivary microbiota structure between the T2DM and control groups (beta diversity; unweighted UniFrac distances, p = 0.001; weighted UniFrac distances, p = 0.001). The phylum Firmicutes was abundant in patients with T2DM, whereas the phylum Bacteroidetes was abundant in controls. The T2DM prediction model by random forest based on salivary microbiota data was verified with a high predictive potential in five cross-validation tests (area under the curve (AUC) = 0.938 (95% CI, 0.824-1.000)). CONCLUSION: Characterization revealed that the salivary microbiota profile of the elderly patients with T2DM is significantly distinct from that of the controls. CLINICAL RELEVANCE: These data indicate the necessity of oral health management based on the characteristics of the salivary microbiota in elderly patients with T2DM. Our findings will contribute to future research on the development of new diagnostic and therapeutic methods for this purpose.

Three-Dimensional Geometric Morphometry of Facial Soft Tissue Changes After Bilateral Sagittal Split Ramus Osteotomy.

ABSTRACT: This study aimed to evaluate the performance of geometric morphometry (GM) to assess the changes in facial soft tissue after orthognathic surgery. Subjects were 27 patients (skeletal class III) who underwent bilateral sagittal split ramus osteotomy and 27 volunteers as a control group. Computed tomography images of each patient were obtained before surgery (T0) and 6 months after surgery (T1). Computed tomography images of 27 volunteers (skeletal class I) were also obtained as a control group. Using a three-dimensional (3D) modeling software, 3D models were created and exported to a 3D surface analyzing software for geometric morphometry and principal component (PC) analysis. Significant differences in facial soft tissue were found in the first and second of 15 PC. The first PC represented variation in the lower facial height, and the second PC represented variation in the anterior-posterior position of the chin. Comparing the pre- and post-operative images, they illustrated that lower facial height was decreased, and the chin and lower lip moved posteriorly. Geometric morphometry showed to be a successful tool to isolate surgery-related changes from interindividual morphological variations.