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.

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 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.

Comparative evaluation of microbial profiles of oral samples obtained at different collection time points and using different methods.

OBJECTIVES: Recently, the oral microbiome has been found to be associated with oral and general health status. Although various oral sample collection protocols are available, the potential differences between the results yielded by these protocols remain unclear. In this study, we aimed to determine the effects of different time points and methods of oral sample collection on the outcomes of microbiome analysis. MATERIALS AND METHODS: Oral samples were collected from eight healthy individuals at four different time points: 2 h after eating, immediately after teeth brushing, immediately after waking up, and 2 h after eating on the subsequent day. Four methods of saliva collection were evaluated: spitting, gum chewing, cotton swab, and oral rinse. Oral microbiomes of these samples were compared by analyzing the bacterial 16S rRNA gene sequence data. RESULTS: The oral microbial composition at the genus level was similar among all sample collection time points and methods. Alpha diversity was not significantly different among the groups, whereas beta diversity was different between the spitting and cotton swab methods. Compared with the between-subject variations, the weighted UniFrac distances between the groups were not minor. CONCLUSIONS: Although the oral microbiome profiles obtained at different collection time points and using different methods were similar, some differences were detected. CLINICAL RELEVANCE: The results of the present study suggest that although all the described protocols are useful, comparisons among microbiomes of samples collected by different methods are not appropriate. Researchers must be aware of the issues regarding the impact of saliva collection methods.

Approximated super multi-view head-mounted display to reduce visual fatigue.

To reduce the visual fatigue of the head-mounted displays, we propose an approximated super multi-view technique in which multiple viewpoints are generated two-dimensionally with an interval smaller than the pupil diameter using the time multiplexing technique, and left and right virtual images are two-dimensionally shifted in synchronization with the viewpoint generation. The proposed technique enlarges the depth of field of eyes to provide the accommodation-invariant feature so that the vergence-accommodation conflict is mitigated. We constructed an experimental system by using two LED arrays for the viewpoint generation and one LCD panel vibrated by two stepping motors. The proposed technique was then experimentally validated.

Microsurgical mandibular reconstruction using a resin surgical guide combined with a metal reconstructive plate.

INTRODUCTION: In mandibular reconstruction, repositioning the mandibular position is still challenging and time consuming. We invented a new re-positioning technique using a resin plate combined with a reconstructive plate in reconstructing the mandible with an osteocutaneous free flap. The purpose of this report is to introduce this technique and evaluate the accuracy of mandibular reconstruction using free flaps. We hypothesized that this technique is precise and can reduce intraoperative plate bending at a low cost and short preparation period. METHODS: Mandibular reconstruction was successfully performed in a total of 10 cases without any complications. In this technique, a pre-bent reconstructive plate was prepared in accordance with a three-dimensional model, and then coated with resin. Intraoperatively, the mandibles were secured by fitting these plates snugly and fixing them using a reconstructive plate. Then the resin was removed and free osteocutaneous free flaps were transfer to the defect. Ten patients with a mean age of 68.2 who underwent mandibular resection for aggressive benign (n = 1) or malignant disease (n = 9) were reconstructed using this technique. Seven cases were reconstructed using fibular osteocutaneous free flaps, while scapular osteocutaneous free flaps were used in the remaining cases. The resections entailed: unilateral symphysis and lateral body in four cases, angle to ipsilateral angle in two, ramus to symphysis in two, and lateral body plus angle to symphysis in one case. The deviation of the mandible was evaluated by measuring the preoperative versus postoperative differences in the distances between six bilateral landmarks. RESULTS: There were no complications and flap failure in any of the 10 cases. No further intraoperative plate bending was required. One case underwent additional mucosal resection due to recurrence of cancer. Three cases were referred to postoperative chemoradiotherapy. Two patients expired during follow-up due to recurrence of cancer. Six cases were put back on a normal diet. The other cases who lacked opposing teeth had to remain on a soft diet. The mean follow-up period was 46.2 months. The average of the absolute deviation values was 1.45 mm. This value was 0.94 mm in six cases with mandibular body defects and 2.26 mm in four cases with mandibular defects involving the ramus. CONCLUSIONS: The present novel technique is simple, quick to prepare, and accurate. This technique can be a viable option for microsurgical mandibular reconstruction.

Removal of a Fixation Screw That Was Forced Into the Postsuperior Maxillary Sinus Wall: Case Report.

We have encountered a rare case in which the subject underwent maxillary sinus floor elevation at another hospital, and a screw to fix the grafted bone substitute was forced into the maxillary sinus and intruded into the bone. Various different foreign bodies have been reported as being forced into the maxillary sinus due to dental treatment, and these foreign bodies are often retained on the maxillary sinus mucous membrane. However, no reports have described a screw forced in and intruded into the peculiar position in the bone, as seen in the present case, which we report here with additional discussion.

Super multi-view near-eye display to solve vergence-accommodation conflict.

A super multi-view (SMV) technique is applied to near-eye displays to solve the vergence-accommodation conflict that causes visual fatigue. The proposed SMV near-eye display employs a high-speed spatial light modulator (SLM), a two-dimensional (2D) light source array, and an imaging optics for each eye. The imaging optics produces a virtual image of the SLM and real images of the light sources to generate a 2D array of viewpoints. The SMV images are generated using a time-multiplexing technique: the multiple light sources sequentially emit light while the SLM synchronously displays corresponding parallax images. A monocular experimental system was constructed using a ferroelectric liquid crystal display and an LED array. A full-parallax SMV image generation with 21 viewpoints was demonstrated and a comparison of full-parallax and horizontal parallax SMV images provided.

Reconstruction of the Alveolar Bone Using Bone Augmentation With Selective Laser Melting Titanium Mesh Sheet: A Report of 2 Cases.

Bone augmentation is used to supplement bone defects during dental implant treatment. In this technique, the area filled with bone prosthetic material is covered with an artificial space-making device or titanium mesh sheet, which must be manually adapted to the bone defect during the procedure before being fixed in place. Selective laser melting (SLM) method can be used to preadapt the titanium mesh sheet based on preoperative CT data. This method enables shorter surgery times compared with conventional titanium mesh sheet methods, as well as regeneration of an ideal alveolar bone shape. Here, we present 2 cases of bone augmentation using the SLM titanium mesh sheet method. The postoperative course was without complications in both cases; neither patient experienced mesh exposure or infection during healing. The SLM titanium mesh sheet method should be considered as a new and effective bone augmentation method.

New Bone Formation Process Using Bio-Oss and Collagen Membrane for Rat Calvarial Bone Defect: Histological Observation.

PURPOSE: We carried out guided bone regeneration of cranial bone defects in rats using the bovine bone substitute Bio-Oss and a collagen membrane and performed histological observations of the bone repair process. MATERIALS AND METHODS: Bone defects were created in the cranial bones of 30 15-week-old Sprague-Dawley rats. We made 3 groups. A is unfilled, B is Bio-Oss, and C is Bio-Oss plus a collagen membrane. At 4 or 8 weeks postoperatively, tissue samples were taken. The Kawamoto technique was used for histological evaluation. RESULTS: There was no new bone formation in group A. In groups B and C, new bone formation was evident around the Bio-Oss. In group C, new bone formation was evident in the centers of the bone defects, detached from the cut edge of the cranial bone. CONCLUSION: Our results suggested that the Bio-Oss acts as a scaffold for bone repair, and the use of a collagen membrane may anchor the Bio-Oss closely to the cranial bone and assist the bone repair response.

Newly Formed Bone Induced by Recombinant Human Bone Morphogenetic Protein-2: A Histological Observation.

PURPOSE: To observe, histologically, bone induced by recombinant human bone morphogenetic protein-2 (rhBMP-2) in onlay grafted and sinus lifted alveolaris. MATERIAL AND METHODS: Eighteen patients were treated with rhBMP-2 at concentration 1.5 mg/mL with an absorbable collagen sponge (ACS). The treated bone was harvested with small trephine bur at 5 or 7 months after surgery for the micro Computer Scanning (CT) and light microscopic observation. RESULTS: Micro CT showed clearly 3-dimensional trabecular bone structure. New bone formation and bone marrow structure were observed in the observed area. Osteoblastic cells existed along the new bone, and osteopontin was localized in the bone matrix weakly. In the connective tissue around the new bone, many CD34-positive blood vessel cells were present. Some tartrate-resistant acid phosphatase (TRAP)-positive osteoclastic cells were observed around bone at this stage. CONCLUSION: The application of rhBMP-2 with ACS induced a new bone accompanied by blood vessels in atrophied alveolaris. This suggests that rhBMP-2 is capable of osteoinductivity in human jaw.

Rapid and Easy Histological Evaluation of Alveolar Human Bone Quality at Dental Implant Sites Using a Nondecalcified Frozen Cryofilm Section Technique: A Technical Report.

INTRODUCTION: The evaluation of bone quality at the site of the alveolar bone for a dental implant is very important. This study presents an easy technique for direct evaluation of alveolar bone quality using nondecalcified cryofilm frozen sections on human alveolar bone core samples. MATERIALS AND METHODS: Core samples harvested from alveolar bone were immediately frozen in cooled hexanen and slowly cut using a disposable tungsten carbide blade; the sliced sections were collected with adhesive cryofilms. Staining was performed using von toluidine blue and von Kossa for microscopic observations. RESULTS: All core samples clearly showed bone structure components of cortical bone, trabecular bone, bone marrow, blood vessels, and bone-related cells. CONCLUSION: These results suggest the efficacy of a nondecalcified cryofilm frozen section technique for histological observation of surgical implant sites.

[Concept of the Pain Management in the Convalescent Rehabilitation].

Convalescent rehabilitation is a treatment designed to facilitate the process of recovery from disease or injury to as normal a condition as possible. The effective rehabilitation is required to improve functions to bring about the highest possible level of independence, physically, psychologically, socially and economically within a limited hospitalization period. Pain often inhibits the effective rehabilitation, and the pain management in the convalescent rehabilitation ward is important. In particular, it is important to evaluate the pain promptly and accurately, and to treat it by a multidisciplinary team approach, preventing a shift to chronic pain. In this article, we describe the role of each member in the convalescent rehabilitation team and the characteristic pains caused by representative diseases.

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.

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.

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.

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.