Characteristics and Prevalence of Staphyloma Edges at Different Ages in Highly Myopic Eyes.

Purpose: The purpose of this study was to determine the characteristics of staphyloma edges in highly myopic eyes and how they progress. Methods: We conducted a cross-sectional analysis using baseline data and a longitudinal study with follow-up data from 256 patients (447 eyes) with high myopia, with a mean (SD) follow-up of 3.79 (0.78) years. Participants were divided into four age groups: children (<13), youth (13-24), mature (25-59), and elderly (>60). Ultrawide-field swept-source optical coherence tomography was used to analyze staphyloma edges, which were divided into four areas: nasal to the optic disc (OD), superior to the macula, inferior to the macula, and temporal to the macula. Results: Staphylomas were significantly more prevalent in the mature (42.49%) and the elderly (51.35%) groups than in the children (13%) and youth (9%) groups. Staphyloma edges were predominantly superior to the macula in the mature and elderly groups. In contrast, staphylomas were rare in children and youth, with their edges mainly located nasal to the OD. The edges of staphylomas located superior and temporal to the macula were more likely to be associated with myopic traction maculopathy. During the follow-up period, 11 new staphyloma edges developed primarily in the mature group (64%). Additionally, 12 edges had an increased degree of protrusion over time, with most cases occurring in the mature (75%) group. Conclusions: The prevalence and location of staphyloma edges show significant variations depending on age. As time progresses, staphyloma edges manifest at distinct sites and increase their protrusion, potentially playing a role in the emergence of fundus complications.

Hangeshashinto for prevention of oral mucositis in patients undergoing hematopoietic stem cell transplantation: a randomized phase II study.

PURPOSE: Oral mucositis (OM) is a side effect associated with cancer treatment. Hangeshashinto (HST), a Kampo medicine, was originally prescribed to treat diarrhea, gastritis, and stomatitis. Several reports have described the effects of HST for OM induced by chemotherapy in patients with gastric or colorectal cancer. In this study, the effects of HST for prevention of OM were investigated in patients undergoing hematopoietic stem cell transplantation (HSCT). METHODS: Thirty patients scheduled to receive allogeneic grafts were enrolled from July 2020 to December 2021. They were randomly assigned to two groups and instructed to wash their mouth using HST dissolved in saline solution or using only saline solution three times a day. The observation period was from the initiation date of the conditioning regimen to the date of engraftment, and the end point was the incidence of OM. RESULTS: Eighteen patients developed OM, the most severe of which was Grade (G)3. There was no significant difference in the incidence of OM between the HST group and the control group. However, a negative correlation tended to be observed between the duration using HST use and the duration of OM (G2-3: P = 0.027, G3: P = 0.047). CONCLUSIONS: The present study demonstrated that HST use did not clearly inhibit onset of OM but showed a tendency to inhibit OM exacerbation. However, further studies are necessary to fully understand the effects of HST on OM in patients undergoing HSCT. TRIAL REGISTRATION: This study was registered in the Japan Registry of Clinical Trials on 7 May 2020 (jRCTs071200012).

Dome-shaped macula with protrusion of inner part of sclera.

Purpose: To report our findings in a patient with a two layered dome shaped macula (DSM) in which only the inner layer of the sclera protruded anteriorly. Observations: An 84-year-old woman with high myopia had a DSM in both eyes. The optical coherence tomographic (OCT) image of the left eye showed a uniform thickening of the foveal sclera, but the DSM of the right eye was split into an inner and outer layer by intrascleral blood vessels running between the two layers. OCT showed that only the inner layer of the sclera protruded anteriorly while the outer layer remained in its normal position. Conclusions and importance: The two layered DSM suggests that the etiology of DSMs may be more complex.

LONGITUDINAL STUDY OF CHANGES IN INNER SCLERAL CURVATURE PATTERNS AND DEVELOPMENT OF POSTERIOR STAPHYLOMAS IN HIGHLY MYOPIC EYES OF CHILDREN AND ADOLESCENTS.

PURPOSE: To determine the longitudinal changes in patterns of inner scleral curvature and development of posterior staphylomas in the eyes of highly myopic youths. METHODS: A retrospective, longitudinal study. Ultra-widefield optic coherence tomographic (UWF-OCT) images from 47 eyes of 24 highly myopic patients with a follow-up period of 2 to 4 years were analyzed. Patients were divided into two groups, the children group younger than 10 years and the adolescents group aged 11 to 19 years. RESULTS: During the follow-up period, the scleral curvature patterns changed in either the horizontal or vertical optical coherence tomographic sections in 27 of the 46 eyes (58.7%) of both groups. The changes were significantly more frequent in children than adolescents. The change in the vertical section from symmetrical to asymmetrical in almost of children was correlated with an increase in the axial length and myopia. Four eyes had a staphyloma at the baseline. The staphyloma developed in six eyes of the remaining 43 eyes (14%). All staphyloma edges were found at or around the optic disc and were oriented in the horizontal direction. CONCLUSION: Our results showed that UWF-OCT images can be used to determine the process of new staphyloma formation and concurrent changes in scleral curvature patterns.

Determining posterior vitreous structure by analysis of images obtained by AI-based 3D segmentation and ultrawidefield optical coherence tomography.

AIMS: To determine the three-dimensional (3D) structure of the vitreous fluid including the posterior precortical vitreous pockets (PPVP), Cloquet's canal and cisterns in healthy subjects by AI-based segmentation of the vitreous of swept-source optical coherence tomography (OCT) images. In addition, to analyse the vitreous structures over a wide and deep area using ultrawidefield swept-source OCT (UWF-OCT). METHODS: Ten eyes of six patients with the mean age was 40.7±8.4 years and the mean refractive error (spherical equivalent) was -3.275±2.2 diopters were examined. RESULTS: In the UWF OCT images, the structure of the vitreous was observed in detail over 23 mm wide and 5 mm area. AI-guided analyses showed the complex 3D vitreous structures from any angle. Cisterns were observed to overlie the PPVP from the anterior. The morphology and locations of the cisterns varied among the subjects but tended to be similar in the two eyes of one individual. Cisterns joined the PPVPs superior to the macula to form a large trunk. This joined trunk was clearly seen in 3D images even in eyes whose trunk was not detected in the B scan OCT images. In some eyes, the vitreous had a complex appearance resembling an ant nest without large fluid-filled spaces. CONCLUSIONS: A combination of UWF-OCT and 3D imaging is very helpful in visualising the complex structure of the vitreous. These technologies are powerful tools that can be used to clarify the normal evolution of the vitreous, pathological changes of vitreous and implications of vitreous changes in various vitreoretinal diseases.

Hospital-based study of risk factors associated with development of myopic macular neovascularization in highly myopic eyes.

INTRODUCTION: Myopic macular neovascularization (MNV) is the most common cause of a reduction of central vision in eyes with pathologic myopia, and it can progress to macular atrophy in the long-term. The aim of this study was to determine the risk factors associated with the development of MNVs. METHODS: There were 17,198 follow-up records from 5,409 eyes of 2,784 highly myopic patients that were reviewed. The general information and ophthalmic information in the records were studied. The significance of the correlations of factors associated with the development and predicting the development of myopic MNV were determined. RESULTS: Being a woman (odds ratio [OR]: 0.727, P<0.001), having a longer axial length (OR = 0.948, P<0.001), a poorer baseline best-correct visual acuity (BCVA, OR = 2.098, P<0.001), having severe myopic maculopathy (overall: P<0.001), prior myopic MNV in the fellow eye (OR = 4.105, P<0.001), presence of patchy atrophy (overall P<0.001), lacquer cracks (OR = 1.718, P<0.001), prior foveal retinal detachment (RD, OR = 3.269, P<0.001), prior macular hole (MH, OR = 0.641, P <0.001), prior macular retinoschisis (OR = 1.533, P<0.001), and prior macular edema (OR = 1.508, P<0.001) were significantly correlated with the development of myopic MNV. Eyes with MNV and patchy atrophy would require an intensive follow-up examination for myopic patients as the fellow eye would have a risk of >70% for the development of myopic MNV in 3-years and nearly 80% in 5-years. CONCLUSIONS: Clinicians need to pay special attention to eyes with severe grades of myopic maculopathy, prior myopic MNV in the fellow eye, presence of patchy atrophy, and prior foveal retinal detachment to determine the onset of myopic MNV.

ANOMALIES OF CHOROIDAL VENOUS STRUCTURE IN HIGHLY MYOPIC EYES.

PURPOSE: To identify anomalies of choroidal venous structure in highly myopic (HM) eyes. METHODS: Widefield indocyanine green angiographic images of 175 HM eyes (refractive error ≤ -6.0D diopters or axial length >26.5 mm) and 100 control eyes taken between January 2014 and December 2018 were reviewed. RESULTS: There were no significant differences in age and gender between HM patients and controls. Three types of changes of large choroidal veins were found in 103 HM eyes (58.86%): Asymmetry of vortex veins in 44 eyes (25.14%), isolated long vein across the macula in 58 eyes (33.14%), and intervortex anastomoses in 25 eyes (14.29%). Similar changes in controls were found in 12 eyes (12%), 0 eye (0%), and 2 eyes (2%), respectively, which were significantly lower than those in the HM group (all P < 0.05). The patterns of asymmetry were affected by steeper staphyloma edges and anastomoses were observed through large trunks and terminal venules. In two eyes with large trunk anastomosis, attenuation of the less dominant vortex vein was observed afterward. CONCLUSION: Choroidal venous anomalies are more common in HM eyes than controls. Choroidal venous structure in HM eyes may be altering continuously, and such changes may underlie the development of myopic maculopathy.

Quantitative Evaluations of Posterior Staphylomas in Highly Myopic Eyes by Ultra-Widefield Optical Coherence Tomography.

Purpose: To determine the shape of posterior staphylomas using ultra-widefield optical coherence tomographic (UWF-OCT) images and to identify the factors contributing to the shape and grade of the staphylomas in eyes with pathologic myopia. Methods: This was an observational case series study. Highly myopic patients who were ≥40 years old with wide or narrow type of macular staphylomas were studied. High myopia was defined as a myopic refractive error (spherical equivalent) greater than -8.0 diopters (D) or an axial length (AL) > 26.5 mm. The maximum diameter and depth of the staphylomas were measured in the 12 radial scans of UWF-OCT images by ImageJ software and were compared between the two types of staphylomas. Results: We studied 197 eyes of 138 patients with a mean age of 64.7 ± 10.4 years and mean AL of 30.0 ± 1.9 mm. The AL was significantly longer in the eyes with the narrow type than the wide type of staphyloma (P = 0.036). Multiple regression analyses showed that age was significantly correlated with the maximum depth/maximum diameter ratio (wide type, P < 0.001; narrow type, P = 0.003) of both types of staphylomas. The AL was significantly correlated with the depth/diameter ratio of only the narrow type of staphylomas (P = 0.005). Conclusions: The significant correlations of age and AL with the wide and narrow types of posterior staphylomas indicate that the factors for their formations may be distinctly different. Quantitative analyses of UWF-OCT images are helpful in determining the shape of the staphylomas.

Structural Abnormalities in the Papillary and Peripapillary Areas and Corresponding Visual Field Defects in Eyes With Pathologic Myopia.

Purpose: To identify structural abnormalities in the papillary and peripapillary area in eyes with pathologic myopia (PM) and normal IOP and to determine their relationship to visual field (VF) defects. Methods: One hundred eight eyes of 70 patients with PM were retrospectively studied. The disc-centered swept source optical coherence tomographic images and the Goldmann VF recorded within 1 year of the optical coherence tomographic examination were analyzed. Four structural abnormalities were identified: lamina cribrosa (LC) defects, ridge protrusions, intrachoroidal cavitations (ICC), and prelaminar schisis. The correspondence of the VF defects with the structural abnormalities was assessed. Results: The mean age, axial length, and optic disc area of the 108 eyes were 58.7 ± 10.0 years, 31.1 ± 2.4 mm, and 4.7 ± 2.2 mm2, respectively. Eighty-five of the 108 eyes (78.7%) had at least one abnormality and 49.4% (42/85) had two or more abnormalities. LC defects, ridge protrusions, ICC, and prelaminar schisis were detected in 47.2%, 33.3%, 21.3%, and 30.6% of the eyes, respectively. VF defects at the corresponding areas of these structural abnormalities were seen in 63% of the eyes with LC defects, 39% of the eyes with ridge protrusions, and 21% of the eyes with ICC. Conclusions: Four kinds of structural abnormalities with corresponding VF defects are commonly observed in the papillary and peripapillary region of eyes with PM. The presence of these abnormalities suggests a possibility of functional damage.

Validation of Soft Labels in Developing Deep Learning Algorithms for Detecting Lesions of Myopic Maculopathy From Optical Coherence Tomographic Images.

PURPOSE: It is common for physicians to be uncertain when examining some images. Models trained with human uncertainty could be a help for physicians in diagnosing pathologic myopia. DESIGN: This is a hospital-based study that included 9176 images from 1327 patients that were collected between October 2015 and March 2019. METHODS: All collected images were graded by 21 myopia specialists according to the presence of myopic neovascularization (MNV), myopic traction maculopathy (MTM), and dome-shaped macula (DSM). Hard labels were made by the rule of major wins, while soft labels were possibilities calculated by whole grading results from the different graders. The area under the curve (AUC) of the receiver operating characteristics curve, the area under precision-recall (AUPR) curve, F-score, and least square errors were used to evaluate the performance of the models. RESULTS: The AUC values of models trained by soft labels in MNV, MTM, and DSM models were 0.985, 0.946, and 0.978; and the AUPR values were 0.908, 0.876, and 0.653 respectively. However, 0.56% of MNV "negative" cases were answered as "positive" with high certainty by the hard label model, whereas no case was graded with extreme errors by the soft label model. The same results were found for the MTM (0.95% vs none) and DSM (0.43% vs 0.09%) models. CONCLUSIONS: The predicted possibilities from the models trained by soft labels were close to the results made by myopia specialists. These findings could inspire the novel use of deep learning models in the medical field.

Posterior vitreous detachment and paravascular retinoschisis in highly myopic young patients detected by ultra-widefield OCT.

The purpose of this study was to determine the relationship between a posterior vitreous detachment (PVD) and retinoschisis (RS) in 73 highly myopic (HM) young patients age 16.4 ± 6.9 years and 24 non-HM children age 8.4 ± 1.5 years. The presence of the paravascular retinal abnormalities was determined in the images obtained by a ultra-widefield OCT (UWF OCT) instrument with an image field of 23 × 20 mm. The results showed that a partial PVD was detected in 15 (21%) of the HM patients, and the number increased significantly with increasing age (P = 0.02). PVDs of any type were not found in the non-HM eyes. The number of microvascular folds also increased with age in the HM patients (P = 0.03). Medium-reflective columnar tissues were present between the detached vitreous and inner retinal surface in 4 (5%) eyes of the HM patients. Myopic RS was found in 3 (4%) HM patients in the paravascular area but not in the macular area. These results suggest that early partial PVD may play a role in pathological and proliferative vitreous changes of HM eyes. An intense vitreoretinal traction with bridging tissues may cause the various paravascular retinal abnormalities. In HM eyes, paravascular RS is already present at an early age which may progress to macular RS with aging.

Continued Increase of Axial Length and Its Risk Factors in Adults With High Myopia.

IMPORTANCE: Pathologic myopia due to an excessive increase of axial length is associated with severe visual impairments. Systematic analyses to determine the rate of and the risk factors associated with the axial elongation in adults with high myopia based on long-term follow-up of a large population are needed. OBJECTIVE: To determine the risk factors associated with axial elongation in adults with high myopia. DESIGN, SETTING, AND PARTICIPANTS: This cohort study used the medical records of 43 201 patient visits in a single-hospital database that were collected from January 3, 2011, to December 28, 2018. A total of 15 745 medical records with the patients' sex, best-corrected visual acuity (BCVA), axial length, type of myopic maculopathy, and the presence or absence of choroidal neovascularization (CNV) were reviewed. Data were analyzed from April 3, 2019, to August 5, 2020. MAIN OUTCOMES AND MEASURES: Changes in the axial length at each examination were calculated. The significance of the associations between the annual increase of the axial length and age, sex, baseline axial length, types of myopic maculopathy, and a history of CNV was determined. Generalized linear mixed models were used to evaluate the strength of the risk factors associated with an increase of the axial length in high myopia. RESULTS: Among 1877 patients with 9161 visits included in the analysis, the mean (SD) age was 62.10 (12.92) years, and 1357 (72.30%) were women. The mean (SD) axial length was 29.66 (2.20) mm with a mean (SD) growth rate of 0.05 (0.24) mm/y. Among the 9161 visits, 7096 eyes (77.46%) had myopic maculopathy and 2477 eyes (27.04%) had CNV. The odds ratio for inducing a severe elongation of the axial length was 1.46 (95% CI, 1.38-1.55) for female sex, 0.44 (95% CI, 0.35-0.56) to 0.63 (95% CI, 13 0.50-0.78) for older than 40 years, 1.33 (95% CI, 1.15-1.54) for BCVA of less than 20/400, 1.67 (95% CI, 1.54-1.81) to 2.67 (95% CI, 2.46-2.88) for baseline axial length of 28.15 mm or greater, 1.06 (95% CI, 0.96-1.17) to 1.39 (95% CI, 1.24-1.55) for the presence of maculopathy, and 1.37 (95% CI, 1.29-1.47) for prior CNV. CONCLUSIONS AND RELEVANCE: This cohort study found continuing axial elongation in adults with high myopia. The risk factors for elongation do not appear to be modifiable, so prevention of myopia may be the best approach to reduce the incidence of pathologic myopia and its complications in the future.

Risk factors associated with the development of aspiration pneumonia in patients receiving radiotherapy for head and neck cancer: retrospective study.

BACKGROUND: Patients with head and neck cancer who are receiving radiotherapy can develop aspiration pneumonia. Determination of the incidence of aspiration pneumonia and the associated risk factors could facilitate the identification of high-risk patients. METHODS: In this retrospective study, we determined the incidence of aspiration pneumonia in 357 patients receiving radiotherapy along with oral care for head and neck cancer. We also performed univariate and multivariable logistic regression analyses to investigate the risk factors for this complication. RESULTS: The incidence of aspiration pneumonia was 17.6%. Hypopharyngeal cancer, grade 3 oral mucositis, and nasogastric tube feeding were independent risk factors. Moreover, the development of aspiration pneumonia was one of the major effects on the discontinuation of radiotherapy. CONCLUSION: Approximately, one-sixth of the patients developed aspiration pneumonia despite appropriate oral care during radiotherapy for head and neck cancer. Aspiration pneumonia during radiotherapy could adversely affect head and neck cancer management.

A retrospective study of factors associated with the development of oral candidiasis in patients receiving radiotherapy for head and neck cancer: Is topical steroid therapy a risk factor for oral candidiasis?

The aims of this study were to investigate the incidence and risk factors for oral candidiasis in patients receiving radiotherapy for head and neck cancer, and to determine the influence of topical steroid therapy on the development of oral candidiasis.We conducted a retrospective study of 300 patients receiving radiotherapy to the head and neck region. The primary endpoint was the incidence of oral candidiasis during radiotherapy. Associations between the incidence of oral candidiasis and various clinical factors were investigated. The cumulative incidence rate of oral candidiasis was calculated using the Kaplan-Meier method and analyzed by the log-rank test and Cox regression. Propensity score-matched analysis was used to assess the influence of topical steroid therapy on the development of oral candidiasis.Oral candidiasis occurred in 75 (25.0%) of the 300 patients. Multivariate analysis identified minimum lymphocyte count and severity of oral mucositis during radiotherapy as independent risk factors for the development of oral candidiasis. Topical steroid therapy for oral mucositis was not associated with the incidence of oral candidiasis according to multivariate and propensity score matching analyses.Oral candidiasis was associated with the suppression of the host's immunity and severe oral mucositis, but not topical steroid therapy. Proper oral health care during radiotherapy and the prevention of severe oral mucositis may reduce the incidence of oral candidiasis.

The effect of abrading and cutting instruments on machinability of dental ceramics.

The aim was to investigate the effect of machining instruments on machinability of dental ceramics. Four dental ceramics, including two zirconia ceramics were machined by three types (SiC, diamond vitrified, and diamond sintered) of wheels with a hand-piece engine and two types (diamond and carbide) of burs with a high-speed air turbine. The machining conditions used were abrading speeds of 10,000 and 15,000 r.p.m. with abrading force of 100 gf for the hand-piece engine, and a pressure of 200 kPa and a cutting force of 80 gf for the air-turbine hand-piece. The machinability efficiency was evaluated by volume losses after machining the ceramics. A high-abrading speed had high-abrading efficiency (high-volume loss) compared to low-abrading speed in all abrading instruments used. The diamond vitrified wheels demonstrated higher volume loss for two zirconia ceramics than those of SiC and diamond sintered wheels. When the high-speed air-turbine instruments were used, the diamond points showed higher volume losses compared to the carbide burs for one ceramic and two zirconia ceramics with high-mechanical properties. The results of this study indicated that the machinability of dental ceramics depends on the mechanical and physical properties of dental ceramics and machining instruments. The abrading wheels show autogenous action of abrasive grains, in which ground abrasive grains drop out from the binder during abrasion, then the binder follow to wear out, subsequently new abrasive grains come out onto the instrument surface (autogenous action) and increase the grinding amount (volume loss) of grinding materials.

Skeletal stability after sagittal split ramus osteotomy with physiological positioning in patients with skeletal mandibular prognathism and facial asymmetry.

The correction of deformities of the jaw in patients with facial asymmetry is challenging because of the high rate of relapse, which may partly be caused by skeletal interference and inappropriate seating of the condylar head. We evaluated outcomes in 30 patients who were treated by short lingual osteotomy with physiological positioning. Nine had facial symmetry (absolute displacement of the menton<2mm), 14 had minor asymmetry (displacement of >2 to <4mm), and 7 severe asymmetry (displacement of >4mm). The postoperative position of the menton (Me) was stable in each group, but deviated by 3.56mm in those with severe asymmetry. This deviation remained immediately after operation and after more than one year in this group, which implies that the Me was not on the mandibular midline. The lateral swing of both sides of the proximal segment did not change immediately after operation in any group. Although short lingual osteotomy with physiological positioning can result in skeletal stability, it is important to assess the association between the dental arch and the mandible using computed tomography to ensure a good outcome in patients with a skeletal class III deformity and facial asymmetry.

The three-dimensional assessment of dynamic changes of the proximal segments after intraoral vertical ramus osteotomy.

OBJECTIVES: The aim of this study was to assess the positional changes of the proximal segments after intraoral vertical ramus osteotomy (IVRO). METHOD: Fifteen patients underwent IVRO and were followed according to the authors' unique postoperative management regimen. The analyses of the positions and angles of the proximal segments were performed on frontal and lateral cephalograms, which were taken before surgery (T1) and within 3 days (T2), at 4 weeks (T3), and later than 6 months after surgery (T4). The three-dimensional positions of the condylar heads were also assessed by CT images, which were taken before and 1 year after surgery. RESULTS: The proximal segments temporarily swung posteriorly and laterally with a center on the condylar head as a fulcrum point at T2 and T3, compared with T1, and they repositioned at T4. The condylar heads moved inferior approximately 2 mm with lateral rotation one year after surgery, as seen in the CT. DISCUSSION: The condylar heads changed their positions physiologically for newly established jaw movement after IVRO with the authors' post-operative management regimen because the post-operative skeletal stability and the jaw function were good and stable using this method.

Effects of Vertical Movement of the Anterior Nasal Spine on the Maxillary Stability After LeFort I Osteotomy for Pitch Correction.

Few reports have so far evaluated the maxillary stability after LeFort I osteotomy (L-1) for pitch correction. In the current study, the authors assessed the SN-PP (palatal plane) to evaluate the skeletal stability after osteotomy with clockwise or counter-clockwise rotation and investigated the effects of anterior nasal spine (ANS) and posterior nasal spine (PNS) movement on the stability of the SN-PP.The SN-PP and the positions of ANS, PNS, and point A were measured on lateral cephalograms before surgery (T1), immediately after surgery (T2), and more than 1 year after surgery (T3).All measured angle and points were stable in 4 cases of counter-clockwise rotation. In the 16 cases of clockwise rotation, T3-T2 of SN-PP, ANS, and point A was -2.05°, -2.56 mm, and -1.64 mm, when the SN-PP increased more than 4° after osteotomy. When the ANS moved downward more than 3 mm, the ANS and point A relapsed significantly by 2.75 and 2.31 mm, while the SN-PP relapsed 1.61° more than 1 year after surgery.When the SN-PP increased by more than 4° or the ANS moved downward by more than 3 mm, the authors suggest shifting the PNS upward instead of moving the ANS downward.

Joining characteristics of titanium-based orthodontic wires connected by laser and electrical welding methods.

This study investigated the possibility of electrical and laser welding to connect titanium-based alloy (beta-titanium and nickel-titanium) wires and stainless-steel or cobalt-chromium alloy wires for fabrication of combination arch-wires. Four kinds of straight orthodontic rectangular wires (0.017 × 0.025 inch) were used: stainless-steel (S-S), cobalt-chromium (Co-Cr), beta-titanium alloy (ß-Ti), and nickel-titanium (Ni-Ti). Homogeneous and heterogeneous end-to-end joints (15 mm long each) were made by electrical welding and laser welding. Non-welded wires (30 mm long) were also used as a control. Maximum loads at fracture (N) and elongation (%) were measured by conducting tensile test. The data (n = 10) were statistically analyzed using analysis of variance/Tukey test (P < 0.05).The S-S/S-S and Co-Cr/Co-Cr specimens showed significantly higher values of the maximum load (ML) at fracture and elongation (EL) than those of the Ni-Ti/Ni-Ti and ß-Ti/ß-Ti specimens for electrical welding and those of the S-S/S-S and Co-Cr/Co-Cr specimens welded by laser. On the other hand, the laser-welded Ni-Ti/Ni-Ti and ß-Ti/ß-Ti specimens exhibited higher values of the ML and EL compared to those of the corresponding specimens welded by electrical method. In the heterogeneously welded combinations, the electrically welded Ni-Ti/S-S, ß-Ti/S-S and ß-Ti/Co-Cr specimens showed significantly (P < 0.05) higher ML and EL than those of the corresponding specimens welded by laser. Electrical welding exhibited the higher values of maximum load at fracture and elongation for heterogeneously welded combinations than laser-welding.