The long and winding road of reprogramming-induced rejuvenation.

Organismal aging is inherently connected to the aging of its constituent cells and systems. Reducing the biological age of the organism may be assisted by reducing the age of its cells - an approach exemplified by partial cell reprogramming through the expression of Yamanaka factors or exposure to chemical cocktails. It is crucial to protect cell type identity during partial reprogramming, as cells need to retain or rapidly regain their functions following the treatment. Another critical issue is the ability to quantify biological age as reprogrammed older cells acquire younger states. We discuss recent advances in reprogramming-induced rejuvenation and offer a critical review of this procedure and its relationship to the fundamental nature of aging. We further comparatively analyze partial reprogramming, full reprogramming and transdifferentiation approaches, assess safety concerns and emphasize the importance of distinguishing rejuvenation from dedifferentiation. Finally, we highlight translational opportunities that the reprogramming-induced rejuvenation approach offers.

Global trends and future prospects of COVID-19 and physical activity: Bibliometric analysis.

BACKGROUND: Containment measures implemented during the COVID-19 pandemic have led to drastic changes in daily life and effects on health behaviors such as decrease in physical activity (PA) levels. This study aims to present a general framework to researchers on COVID-19 and PA research in relation with changes in studies within years, current trend topics, gaps in the research field and possible future trends. METHODS: A total of 1819 articles indexed in the WoS core collection database were analyzed according to publication year, citation, country and institution collaborations, coword, co-citation networks, concept-topic trends and topic clusters using bibliometric analysis. RESULTS: The most productive country was the USA(n = 335), and the most productive institution was University of London in UK (n = 38). The most cited publication was the study by Ammar et al, (2020) (n = 188). In 2020, the most popular topics were PA and health meanwhile in 2021 behavior, lifestyle, social media and in 2022 habits, long COVID, sleep quality topics were in the foreground. Studies in 2023 focus on how COVID-19 affects PA habits and the associations between COVID-19-based anxiety and sleep patterns. These studies focused especially on effects of sport participation on life quality, diet, depression, mental health on young athletes, children, adolescent persons, older adult groups. CONCLUSIONS: An important gap in the study area is research on effect of changing lifestyle due to pandemic on individuals and the society during the Post COVID-19 period. If benefits of PA will not be limited to only physical benefits and psychological emotional, cognitive and social benefits are also taken into consideration, it is important that researchers conduct long-term and widescale observations.

Bibliometric Analysis of Published Original Research Articles on Leisure Constraints between 1991 and 2019.

Background: The decrease in the frequency and duration of participation in leisure activities has negative effects on the physical, cognitive and psychological health of individuals. In this context, identifying the obstacles, which prevent individuals from participating in leisure activities, may offer important clues to institutions and organizations in taking measures to increase participation. Methods: The bibliometric analysis method was used in this study. The research was carried out with 306 articles scanned from the Web of Science (WoS) core database between 1991 and 2019. Results: Studies conducted in leisure area increased systematically according to 5-year periods and mostly authors from USA, Australia and Canada produced them. The mainstream subjects, which attracted the attention of researchers during recent years, are detected to be self-efficacy, segmentation, mental health and fear related to intrapersonal constraint topics. Conclusion: In order to cope with physical and mental health problems resulting from aging of the world population, and technological developments, and negative effects generated by inactive modern life style, priority should be given to studies on leisure constraints to be conducted on a more comprehensive basis. Another suggestion is to encourage health policies and applications which can increase participation in leisure activities.

Near-physiological-temperature serial crystallography reveals conformations of SARS-CoV-2 main protease active site for improved drug repurposing.

The COVID-19 pandemic has resulted in 198 million reported infections and more than 4 million deaths as of July 2021 (covid19.who.int). Research to identify effective therapies for COVID-19 includes: (1) designing a vaccine as future protection; (2) de novo drug discovery; and (3) identifying existing drugs to repurpose them as effective and immediate treatments. To assist in drug repurposing and design, we determine two apo structures of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) main protease at ambient temperature by serial femtosecond X-ray crystallography. We employ detailed molecular simulations of selected known main protease inhibitors with the structures and compare binding modes and energies. The combined structural and molecular modeling studies not only reveal the dynamics of small molecules targeting the main protease but also provide invaluable opportunities for drug repurposing and structure-based drug design strategies against SARS-CoV-2.

Can renewable energy be used as an effective tool in the decarbonization of the Mediterranean region: fresh evidence under cross-sectional dependence.

Many studies in the literature confirm the validity of the technique effect, which improves the quality of the environment by investigating whether an inverted U-shaped relationship exists between environmental pollution and economic growth. Ignoring the role of the technological obsolescence effect, which may also exert influence on an economy, these studies reach an optimistic conclusion for growth policies. By controlling renewable energy, this study examines the existence of the obsolescence effect by constructing an N-shaped relationship between economic growth and environmental degradation for the most vulnerable countries in the Mediterranean region to climate change. We conducted a battery of cross-sectional dependence tests, second-generation panel unit root, and cointegration tests in 17 selected Mediterranean countries covering 1990-2017. The results provide evidence of an N-shaped relationship between economic growth and environmental degradation. The study provides important policy recommendations and discusses how renewable energy can be deployed to reduce CO2 emissions.

Investigation of the Exercise Dependence of Athletes Doing Kickboxing, Taekwondo, and Muay Thai.

Debates about the conditions in which the frequency and intensity principles of regular exercise, depending on the fact that a sports background can be accepted as extremism, are still a controversial topic. The purpose of this research was to investigate the exercise dependence of athletes who practice Kickboxing, Taekwondo, and Muay Thai. The study included 141 athletes, consisting of 87 men and 54 women. The Exercise Dependence Scale-21 (EDS-21), composed of 21 items developed by Hausenblas and Downs and adapted into the Turkish version by Yeltepe and Ikizler, was applied to the athletes. As a result of the research, while athletes showed more sensitivity to the EDS (=71.41), this scale was also defined as symptomatic. It was found that five athletes (3.5%) were asymptomatic-nondependent, 117 athletes (83.0%) were symptomatic-nondependent, and 19 athletes (13.5%) were at risk for exercise dependence. It was determined that athletes were at risk for exercise dependence as follows: Eight athletes were doing Kickboxing, ten athletes were doing Taekwondo, and one athlete was doing Muay Thai. A significant difference was observed according to years of regular training and number of trainings per a day. Other variables presented no significant differences. It was possible to say that years of regular training could be effective in revealing exercise dependence.

The impact of economic growth, energy consumption, trade openness, and financial development on carbon emissions: empirical evidence from Turkey.

This study examines the impact of economic growth, energy consumption, trade openness, financial development on carbon emissions for the case of Turkey by using annual time series data for the period of 1960-2013. The Lee and Strazicich test suggests that the variables are suitable for applying the bounds testing approach to cointegration. The cointegration analysis reveals that there exists a long-run relationship between the per capita real income, per capita energy consumption, trade openness, financial development, and per capita carbon emissions in the presence of structural breaks. The results show that in the long run, carbon emissions are mainly determined by economic growth, energy consumption, trade openness, and financial development. The VECM Granger causality analysis indicates a long-run unidirectional causality running from economic growth, energy consumption, trade openness, and financial development to carbon emissions. The findings also show that the EKC hypothesis is valid for Turkey both in the long run and short run. The study provides some implications for policy makers to decrease carbon emissions in Turkey.

Effect of St.John's wort (Hypericum perforatum) oily extract for the care and treatment of pressure sores; a case report.

ETHNOPHARMACOLOGICAL RELEVANCE: Topical formulations such as oily extracts or ointments prepared with the flowering aerial parts of St. John's wort (Hypericum perforatum L., Hypericaceae) have been used in the management of a wide range dermatological problems including superficial wounds and burns, bruises, contusions and many others in the worldwide traditional medicines. AIM OF THE STUDY: This is the first case study reporting the beneficial effects of an oily extract of St. John's wort in the treatment of pressure sores in a intensive care unit (ICU) patient. MATERIAL AND METHODS: The oily extract of St. John's wort was applied to a volunteer patient at ICU daily for forty successive days for wound care and treatment. Healing status was monitored macroscopically by measuring the wound size and stages at certain intervals as well as histopathological evaluation of the tissue sections taken at the initial and final dates of treatment. RESULTS: Evaluation of the results obtained from the macroscopical and histopathological experimentation have shown that oily extract of St. John's wort provided significant efficacy for the treatment of pressure sore wounds. CONCLUSION: St. John's wort oily extract may be suggested as a cost-effective option for the prevention or treatment of pressure sores in ICU patients.

Comparison of lornoxicam and low-dose tramadol for management of post-thyroidectomy pain.

OBJECTIVES: The present study sought to compare the analgesic efficacy and adverse effects of intravenous (IV) lornoxicam and tramadol to investigate if lornoxicam is a reasonable alternative to a weak opioid for post-thyroidectomy pain. METHODS: Fifty patients of American Society of Anesthesiologists class I or II, 18 to 65 years of age, and who underwent thyroidectomy were assigned to 2 groups in a randomized manner. Group L received 8 mg of lornoxicam IV and Group T received 1 mg/kg of tramadol IV at conclusion of the operation. Pain intensity of patients was recorded at 15 and 30 minutes, and at 1, 2, 3, 4, 6, 12, and 24 hours after the initial dose with Numerical Rating Scale (NRS) and Ramsey Sedation Scale. Electrocardiogram, heart rate, systolic/diastolic and average artery pressure and peripheral oxygen saturations were monitored continuously during this period. Patients completed satisfaction questionnaires at 24th hour. RESULTS: Both drugs produced acceptable analgesia; however, significantly fewer patients reported 1 or more adverse events with lornoxicam than with tramadol. Most commonly seen in Group T was nausea/vomiting. NRS scores at 15 minutes, 30 minutes, and 1 hour were lower in Group L than in Group T (p<0.05), but there was no significant difference between groups after postoperative first hour. First analgesic requirement time was significantly longer in Group L compared to Group T (p<0.001). No serious complications were seen in either group. CONCLUSION: Lornoxicam is a safe and effective analgesic that may be used with fewer complications than low-dose tramadol for treatment of moderate to severe postoperative pain.

Comparison of final irrigation techniques in removal of calcium hydroxide.

The aim of this study was to compare new irrigation systems with a conventional irrigation technique for the removal of inter-appointment calcium hydroxide [Ca(OH)2 ]. Forty-seven extracted human single-rooted teeth were instrumented, and Ca(OH)2 paste was placed into root canals by using a lentulo spiral at the apical third. Teeth were randomly divided into three groups according to different irrigation protocols using a 30-gauge slot-tipped needle, EndoVac system and ProUltra® PiezoFlow™ ultrasonic irrigation system. Scanning electron microscopic images of the selected root canal surfaces (cervical, middle and apical third) were evaluated using a 5-grade scale. The influence of the irrigation system was evaluated using a two-way analysis of variance test and Tukey's test. The EndoVac and PiezoFlow groups demonstrated the lowest scale values (cleanest canals); however, there was no statistical difference between these two groups. The conventional irrigation group exhibited significantly higher scores (P < 0.05). The conventional needle irrigation was not sufficient to remove Ca(OH)2 from the root canal system. Irrigation with EndoVac and PiezoFlow™ ultrasonic irrigation systems improved the removal of the intracanal medicament resulting in cleaner root canal walls.

Effect of sodium ascorbate on the bond strength of silorane and methacrylate composites after vital bleaching.

We investigated the effect of sodium ascorbate (SA) on the microtensile bond strengths (MTBSs) of different composites to bovine enamel after vital bleaching with hydrogen peroxide (HP) or carbamide peroxide (CP). Thirty bovine incisors were randomly divided into five groups and treated with no bleaching application (control), 35% HP alone, 35% HP+10% SA for 10 minutes (HP+SA), 16% CP alone, or 16% CP+10% SA for 10 minutes (CP+SA). Specimens were restored with Silorane adhesive and Filtek Silorane composite (designated as S/group) or with Clearfil SE bond and Filtek Supreme XT (designated as F/group). Composite build-up was created on the enamel. Sectioned specimens (n=10 per group; 1 mm2; cross-sectional area) were created and stressed in a universal testing machine at 1 mm/min crosshead speed. The application of 10% SA immediately after bleaching with 16% CP or 35% HP increased the enamel MTBS, regardless of the adhesive/composite resin used. The resulting MTBS values were similar to those of the control groups. Use of 16% CP and 35% HP alone decreased the enamel MTBS, regardless of the adhesive/composite resin used, with F/CP+SA=F/HP+SA=F/CP=S/CP+SA=S/HP+SA=S/C>S/CP=S/HP=F/CP=F/HP (p<0.05). We concluded that the application of SA for 10 minutes immediately after vital bleaching increases the enamel BS for dimethacrylate- and silorane-based composites.

Effect of sodium ascorbate on the bond strength of silorane and methacrylate composites after vital bleaching

We investigated the effect of sodium ascorbate (SA) on the microtensile bond strengths (MTBSs) of different composites to bovine enamel after vital bleaching with hydrogen peroxide (HP) or carbamide peroxide (CP). Thirty bovine incisors were randomly divided into five groups and treated with no bleaching application (control), 35% HP alone, 35% HP + 10% SA for 10 minutes (HP + SA), 16% CP alone, or 16% CP + 10% SA for 10 minutes (CP + SA). Specimens were restored with Silorane adhesive and Filtek Silorane composite (designated as S / group) or with Clearfil SE bond and Filtek Supreme XT (designated as F / group). Composite build-up was created on the enamel. Sectioned specimens (n = 10 per group; 1 mm2; cross-sectional area) were created and stressed in a universal testing machine at 1 mm/min crosshead speed. The application of 10% SA immediately after bleaching with 16% CP or 35% HP increased the enamel MTBS, regardless of the adhesive / composite resin used. The resulting MTBS values were similar to those of the control groups. Use of 16% CP and 35% HP alone decreased the enamel MTBS, regardless of the adhesive / composite resin used, with F / CP + SA = F / HP + SA = F / CP = S / CP + SA = S / HP + SA = S / C > S / CP = S / HP = F / CP = F / HP (p < 0.05). We concluded that the application of SA for 10 minutes immediately after vital bleaching increases the enamel BS for dimethacrylate- and silorane-based composites.

Effects of air-polishing powders on color stability of composite resins

OBJECTIVES: The purpose of this study was to investigate the effect of different air-polishing powders on the color stability of different types of composite resin restorative materials. MATERIAL AND METHODS: Thirty cylindrical specimens (15×2 mm) were prepared for each of 7 composite resin restorative materials. All specimens were polished with a series of aluminum oxide polishing discs (Sof-Lex). The prepared specimens of each composite resin were randomly divided into 3 groups of 10 specimens each, for control (Group-C) and two air-powder applications (Group-CP: Cavitron Prophy-Jet; Group-PS: Sirona ProSmile prophylaxis powder). A standard air-polishing unit (ProSmile Handly) was used. All specimens were air-powdered for 10 s at 4-bar pressure. The distance of the spray nosel from the specimens was approximately 10 mm and angulation of the nosel was 90°. Specimens were stored in 100 mL of coffee (Nescafe Classic) for 24 h at 37°C. Color measurement of all specimens was recorded before and after exposure to staining agent with a colorimeter (Minolta CR-300). Color differences (∆E*) between the 2 color measurements (baseline and after 24 h storage) were calculated. The data were analyzed with a 2-way ANOVA test, and mean values were compared by the Tukey HSD test (p<0.05). RESULTS: According to the 2-way ANOVA results, composite resin restorative materials, air-polishing powders, and their interaction were statistically significant (p<0.05) For Aelite Aesthetic Enemal, Filtek Z250, Grandio, CeramX Mono, and Quixfil composite resin restorative materials, no significant difference was observed between Group-PS and Group-CP (p>.05) and these groups demonstrated the highest ∆E* values. For Filtek Silorane and IntenS, the highest ∆E* values were observed in Group-PS. The lowest ∆E* values for all composite resin groups were observed in Group-C. When comparing the 7 composite resin restorative materials, Aelite Aesthetic Enemal demonstrated significantly less ∆E* values than the other composite resins tested. The highest ∆E* values were observed in Quixfil. CONCLUSION: Except for Quixfil, all control groups of composite resins that were polished Sof-Lex exhibited clinically acceptable ∆E values (<3.7). Air-polishing applications increased the color change for all composite resin restorative materials tested. Composite restorations may require re-polishing after air-polishing.

Effects of air-polishing powders on color stability of composite resins.

OBJECTIVES: The purpose of this study was to investigate the effect of different air-polishing powders on the color stability of different types of composite resin restorative materials. MATERIAL AND METHODS: Thirty cylindrical specimens (15×2 mm) were prepared for each of 7 composite resin restorative materials. All specimens were polished with a series of aluminum oxide polishing discs (Sof-Lex). The prepared specimens of each composite resin were randomly divided into 3 groups of 10 specimens each, for control (Group-C) and two air-powder applications (Group-CP: Cavitron Prophy-Jet; Group-PS: Sirona ProSmile prophylaxis powder). A standard air-polishing unit (ProSmile Handly) was used. All specimens were air-powdered for 10 s at 4-bar pressure. The distance of the spray nosel from the specimens was approximately 10 mm and angulation of the nosel was 90°. Specimens were stored in 100 mL of coffee (Nescafe Classic) for 24 h at 37°C. Color measurement of all specimens was recorded before and after exposure to staining agent with a colorimeter (Minolta CR-300). Color differences (∆E*) between the 2 color measurements (baseline and after 24 h storage) were calculated. The data were analyzed with a 2-way ANOVA test, and mean values were compared by the Tukey HSD test (p<0.05). RESULTS: According to the 2-way ANOVA results, composite resin restorative materials, air-polishing powders, and their interaction were statistically significant (p<0.05) For Aelite Aesthetic Enemal, Filtek Z250, Grandio, CeramX Mono, and Quixfil composite resin restorative materials, no significant difference was observed between Group-PS and Group-CP (p>.05) and these groups demonstrated the highest ∆E* values. For Filtek Silorane and IntenS, the highest ∆E* values were observed in Group-PS. The lowest ∆E* values for all composite resin groups were observed in Group-C. When comparing the 7 composite resin restorative materials, Aelite Aesthetic Enemal demonstrated significantly less ∆E* values than the other composite resins tested. The highest ∆E* values were observed in Quixfil. CONCLUSION: Except for Quixfil, all control groups of composite resins that were polished Sof-Lex exhibited clinically acceptable ∆E values (<3.7). Air-polishing applications increased the color change for all composite resin restorative materials tested. Composite restorations may require re-polishing after air-polishing.

Effect of filler ratio in adhesive systems on the shear bond strength of resin composite to porcelains.

This in vitro study evaluated the effect of six different adhesive systems on the shear bond strength of resin composite to feldspathic and low-fusing porcelains. Sixty porcelain blocks were prepared for each low-fusing (Matchmaker) and feldspathic (MVK95) porcelain specimen. After surface preparation, the porcelain specimens were divided into six groups (n = 10) for different adhesive systems (Adper Prompt L-Pop, QuadrantUnil Bond, Te-Econom, PQ1, One-StepPlus and Prime&Bond NT). After adhesive application, a universal resin composite (FiltekZ250) was condensed on the specimens. The prepared specimens were then stored in distilled water at 37 degrees C for 24 hours, then all the samples were thermal cycled 1000 times between 5 degrees C and 55 degrees C. Shear testing was performed on a universal test machine using a crosshead speed of 0.5 mm/minute. The statistical analysis of the bond strength data included two-way ANOVA. Then, the means were compared by Tukey HSD test (alpha = 0.05). The lowest bond strength was observed in Adper Prompt L-Pop. No statistically significant difference was observed between One-Step Plus and Prime&Bond NT. The highest bond strength was observed in PQ1. When low-fusing or feldspathic porcelain restorations are repaired with resin composite, self-etching adhesive systems may not be indicated. If maximum bond strength is the goal in porcelain resin bonding, adhesive systems that have a high filler ratio should be used.

Effects of polishing procedures on color stability of composite resins

The purpose of this study was to investigate the effect of different polishing methods on color stability of posterior, universal and nanohybrid composite resin restorative materials upon exposure to a staining agent. Twenty-five specimens were prepared for each of 5 different composite resins (Filtek Z250, Filtek P60, Quadrant LC, Grandio and Filtek Supreme). Specimens were divided into 5 groups and different polishing procedures, including polishing discs (Pd), polishing discs then diamond polishing paste (PdP), polishing discs then a liquid polishing system (Biscover) (PdB), and combinations of these (PdPB) were used. Unpolished specimens served as the control (C). The specimens were stored for 48 h in a coffee solution. The color of all specimens was measured before and after exposure with a colorimeter, and total color change (DE*) were calculated. The data were analyzed with a two-way ANOVA and the means were compared by Tukey HSD test (a=0.05). The lowest color difference was observed in the groups PdP and C, while the highest color difference was observed in PdPB, and PdB. When comparing the five different restorative materials, no significant difference was observed between FiltekP60 and FiltekZ250, and these materials demonstrated significantly less color change than Quadrant LC and the nanohybrid materials (Grandio, Filtek Supreme). The posterior (Filtek P60) and universal (Filtek Z250) composite resin restorative materials, which do not contain tetraethyleneglycol dimethacrylate (TEGDMA), were found to be less stainable than the nanohybrid (Grandio, Filtek Supreme) and universal (Quadrant LC) composite resins, which contain TEGDMA. The use of diamond polishing paste after polishing with polishing discs significantly decreased staining when compared to the groups that used polishing discs alone, for all restorative materials tested. The highest color change values were obtained for the specimens that were polished with the...

Effects of polishing procedures on color stability of composite resins.

The purpose of this study was to investigate the effect of different polishing methods on color stability of posterior, universal and nanohybrid composite resin restorative materials upon exposure to a staining agent. Twenty-five specimens were prepared for each of 5 different composite resins (Filtek Z250, Filtek P60, Quadrant LC, Grandio and Filtek Supreme). Specimens were divided into 5 groups and different polishing procedures, including polishing discs (Pd), polishing discs then diamond polishing paste (PdP), polishing discs then a liquid polishing system (Biscover) (PdB), and combinations of these (PdPB) were used. Unpolished specimens served as the control (C). The specimens were stored for 48 h in a coffee solution. The color of all specimens was measured before and after exposure with a colorimeter, and total color change (DeltaE*) were calculated. The data were analyzed with a two-way ANOVA and the means were compared by Tukey HSD test (alpha=0.05). The lowest color difference was observed in the groups PdP and C, while the highest color difference was observed in PdPB, and PdB. When comparing the five different restorative materials, no significant difference was observed between FiltekP60 and FiltekZ250, and these materials demonstrated significantly less color change than Quadrant LC and the nanohybrid materials (Grandio, Filtek Supreme). The posterior (Filtek P60) and universal (Filtek Z250) composite resin restorative materials, which do not contain tetraethyleneglycol dimethacrylate (TEGDMA), were found to be less stainable than the nanohybrid (Grandio, Filtek Supreme) and universal (Quadrant LC) composite resins, which contain TEGDMA. The use of diamond polishing paste after polishing with polishing discs significantly decreased staining when compared to the groups that used polishing discs alone, for all restorative materials tested. The highest color change values were obtained for the specimens that were polished with the Biscover liquid polish system (PdB and PdPB groups).

Intravitreal triamcinolone improves recovery of visual acuity in nonarteritic anterior ischemic optic neuropathy.

BACKGROUND: The visual outcome in untreated nonarteritic anterior ischemic optic neuropathy (NAION) is dismal. Because intravitreal triamcinolone (IVTA) has shown promise in improving edematous retinal disorders, a pilot trial of this therapy in NAION was considered reasonable. METHODS: Four eyes of 4 patients with severe visual loss due to NAION were treated with 4 mg IVTA (study group). The control group consisted of 6 consecutive patients with NAION who received no treatment. Patients were evaluated by the visual acuity and visual field measurements of the Early Treatment Diabetic Retinopathy Study (ETDRS) and fluorescein angiography. RESULTS: All patients completed at least 9 months of follow-up. In the study group, the mean improvement in visual acuity were 4, 5.8, and 6.2 ETDRS lines at the first and third weeks and final visit, respectively. Optic disc swelling and leakage had markedly decreased at the first postinjection week and had disappeared by the third week examination in all eyes. In the control group, the mean improvements in visual acuity were 0, 0.7, and 1.3 ETDRS lines at the first and third weeks and final visit, respectively. Control eyes showed resolution of the optic disc swelling between the fourth week and third month visits. No marked change in visual field defects was observed in either group. CONCLUSIONS: IVTA provided relatively improved recovery of visual acuity and relatively rapid resolution of optic disc swelling in a small sample of patients with acute NAION. It did not provide visual field improvement. A larger trial is merited by the results of this small pilot study.

The pH changes of calcium hydroxide mixed with six different vehicles.

OBJECTIVE: The aim of this study was to determine the pH values of calcium hydroxide mixed with sterile saline, glycerin, Xylocaine pump spray, Citanest Octapressin, 0.2% chlorhexidine solution, and Ultracaine DS. STUDY DESIGN: pH values of all vehicles were measured by a pH microelectrode before calcium hydroxide powder was added to 2 mL of the vehicle until the solutions were saturated (n = 10). After all the saturated samples were prepared, pH was remeasured at 0, 10, 20, 30, and 45 minutes; 1, 24, and 48 hours; and 7 days. RESULTS: When pH changes over the time course were compared, there were no statistically significant differences among mean pH values of 0, 10, 20, 30, 45 minutes, 1 hour, and 24 hours (P = .754) and mean pH values of these groups were significantly lower than the mean pH value of 48 hours and 7 days (P < .05). The highest mean pH value was observed at day 7. When different vehicles were compared, the lowest mean pH value was observed in sterile saline. The mean pH value of Xylocaine was the highest (P < .05). CONCLUSION: The result of this study indicated that when calcium hydroxide powder was mixed with glycerin, Xylocaine pump spray, Citanest Octapressin, 0.2% chlorhexidine solution, Ultracaine DS, and sterile saline solution, the mixtures became very highly alkaline. However, the pH values of the mixtures increased significantly after 24 hours. When one of these vehicles is used for root canal medication, a calcium hydroxide mixture might be left in place at least 7 days.

Nonsurgical endodontic retreatment of geminated teeth: a case report.

The purpose of this case presentation is to describe nonsurgical retreatment of anterior teeth with gemination. A 21-year-old male patient was referred for endodontic treatment of his maxillary left lateral incisor. In the clinical examination, a large crown was observed in the left maxillary incisor region when compared with the right maxillary lateral incisor. In the present case, a tooth gemination of a maxillary lateral incisor has been described. A periapical radiograph showed that the tooth had partially separated two crowns having a single root and one root canal, but the access cavity of the distal crown had not been opened, and the root canal had been obturated with single cone technique. Nonsurgical endodontic retreatment was decided for geminated lateral incisor. At the 6-month follow-up, the tooth was asymptomatic and there was no radiolucency around the apical region.