The use of pulse oximetry in evaluation of pulp vitality in immature permanent teeth

Background and aim: The current methods of pulp vitality assessment, either electric or thermal, are of limited use in children. Recently, traumatized and immature teeth may not respond to such methods and because such methods require subjective responses, it may not provide accurate results particularly in children. Pulse oximetry, an atraumatic approach, is used to measure oxygen saturation in vascular system. The aim of this study was to investigate the use of pulse oximetry to evaluate pulp vitality status in immature permanent teeth. Methods and materials: The study was conducted on 329 maxillary central and lateral incisors in children. The negative control group consisted of 10 root filled teeth. Systemic oxygen saturation was first measured on the thumb of the individual using a custom-made sensor. Oxygen saturation values of the teeth were then evaluated. The correlation between oxygen saturation measurement obtained from finger and tooth, and the correlation between oxygen saturation values and stage of root development were analyzed. A further comparison was made between the teeth with open and closed apex. Results: Mean oxygen values recorded in the patient's finger were 97.17, and mean oxygen values in the maxillary central and lateral incisors were 86.77 and 83/92, respectively. There was no significant correlation between blood oxygen levels in the finger and in the teeth. (P > 0.05) There was a significant negative correlation between the stage of root development and the blood oxygen levels in the patients' teeth. (P < 0.05) Mean oxygen values in the teeth with open apex were significantly higher than the teeth with closed apex. (P < 0.001). Conclusion: Vital teeth provided consistent oxygen saturation readings, and non-vital teeth recorded no oxygen saturation values. During tooth development, the oxygen saturation values decreased. These findings confirm that the pulse oximetry is capable of detecting the pulpal blood flow and oxygen saturation. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd

Spectrophotometric determination of pH and its influence in soils

It would be beneficial to develop an alternative pH measurement technique for soils, since the standard glass electrode method suffers deficiencies with unpredictability in liquid junction potential, high drift and the necessity for electrode calibration with variable ionic strength solutions if high accuracy is required. Other problems with the electrode method for use in soils include clogging of the porous fiber of electrodes, and the “suspension effect”, which can result in a negative bias when there is substantial H+ present on exchange sites. Spectrophotometric methods using indicators offer an alternative to eliminate several inherent issues with potentiometric pH measurement. This approach has been widely used in for pH determination of marine waters due to the high reproducibility achievable (≥ 0.001 pH units) but has not previously been developed for soils. The aims of this thesis were i) to develop a spectrophotometric method for measuring soil pH in the circumneutral (5-8) and acidic ( 0.95) with values determined using a glass electrode in both water and CaCl₂ soil extracts. Similar precision of ±0.02-0.08 pH unit was obtained for measurement on replicate soil extracts for both spectrophotometric and glass electrode methods. The application of the spectrophotometric method was then extended to use with acidic soils by employing an indicator, bromocresol green, with a lower pKa; again, a strong correlation (r2 > 0.99) was achieved between spectrophotometric and glass electrode pH measurements. In the next experiment, a mixed dye (bromophenol blue, bromocresol purple, m-cresol purple, and thymol blue) method was developed that has a much wider working pH range of 3-9; in comparison the working pH range of single dye methods is approx. ±1 pH unit from their pKa. In the mixed-dye method, pH was calculated based on ratio of absorbance at selected two wavelengths and individual dye properties using fundamental equations derived from Beer’s law. The accuracy of the method was found to be within ±0.00-0.06 pH units against certified pH buffers. In the last experiment, measurements and modelling was conducted to evaluate the consistency of the thermodynamics of the soil carbonate system. pH was calculated from a known concentration of pCO₂ applied for soil solution equilibration and alkalinity titration and then comparing the results with pH measured using spectrophotometer and glass electrode. The internal consistency of the soil carbonate system was shown with a precision of ±0.03 pH units. Difference of calculated pH from measured pH was within 0.00-0.1 pH units in soil solutions with alkalinity > 0.5 meq L⁻¹. In conclusion, the application of novel spectrophotometric pH measurement methods for soils has been developed. The indicators which have been calibrated allow wider soil pH measurement between 3-9 which is also useful for other application such as oceanic pH. This study will provide a better understanding of the role of pH in illuminating acid-base reactions in soils, especially including the geochemically significant carbon dioxide system.Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 201

Constraining the carbonate system in soils via testing the internal consistency of pH, pCO(2) and alkalinity measurements

Inorganic carbon exists in various dissolved, gaseous and solid phase forms in natural waters and soils. It is important to accurately measure and model these forms to understand system responses to global climate change. The carbonate system can, in theory, be fully constrained and modelled by measuring at least two of out of the following four parameters: partial pressure (pCO2), total alkalinity (TA), pH and dissolved inorganic carbon (DIC) but this has not been demonstrated in soils. In this study, this "internal consistency" of the soil carbonate system was examined by predicting pH of soil extracts from laboratory measurement of TA through alkalinity titration for solutions in which pCO2 was fixed through equilibrating the soil solution with air with a known pCO2. This predicted pH (pHCO2) was compared with pH measured on the same soil extracts using spectrophotometric and glass electrode methods (pHspec and pHelec). Discrepancy between measured and calculated pH was within 0.00-0.1 pH unit for most samples. However, more deviation was observed for those sample with low alkalinity (≤ 0.5 meq L-1). This is likely attributable to an effect of dissolved organic matter, which can contribute alkalinity not considered in the thermodynamic carbonate model calculations; further research is required to resolve this problem. The effects of increasing soil pCO2 was modelled to illustrate how internally consistent models can be used to predict risks of pH declines and carbonate mineral dissolution in some soils.Sima Bargrizan, Ronald J. Smernik and Luke M. Mosle

Spectrophotometric measurement of the pH of soil extracts using a multiple indicator dye mixture

This paper describes the development of a spectrophotometric method with an expanded pH range of 3–9 that uses a mixed indicator solution (equimolar bromophenol blue, bromocresol purple, m‐cresol purple and thymol blue). The method uses measurements of absorbance of the dye mixture at two wavelengths (434 and 585 nm), chosen to represent the average acid and base peak maxima of the individual dyes within the mixture. The ratio of absorbance at these two wavelengths was used to calculate pH based on measured dye properties (pKa, molar absorptivity) and fundamental equations derived from Beer's law. The mixed dye spectrophotometric pH measurement was tested using certified pH buffers (pH (NBS/NIST) 4.00, 6.86, 9.18) and was found to be accurate to within ± 0–0.06 pH units. Measurements made with the mixed dye showed good correlation against conventional soil pH measurement using a glass electrode (r = 0.99), and also an alkalinity titration (r = 0.99) through the pH range 3–9. The average standard deviation was 0.07 for spectrophotometric soil pH measurement (n = 30) using the dye mixture. The mixed dye technique expands the working range of spectrophotometric pH measurement methods in soils and other applications.S. Bargrizan, R.J. Smernik, L.M. Mosle

The application of a spectrophotometric method to determine pH in acidic (pH < 5) soils

Available online 24 April 2018pH is a "master variable" controlling many biogeochemical processes in soils. Acid sulfate soils undergo rapid and large pH changes from circumneutral pH under anaerobic soil conditions to sulfuric soils with ultra (pH  4) and transformed to sulfuric soils (pH  0.99) to glass electrode measurements under acidic conditions with high metal availability. The method has potential to improve understanding of biogeochemical processes in ultra and extremely acidic soils.Sima Bargrizan, Ronald J. Smernik, Rob W. Fitzpatrick, Luke M. Mosle

Sequential supernumerary teeth development in a non-syndromic patient; report of a rare case.

Isolated impacted supernumerary teeth are quite rare, but they can be seen associated with several syndromes such as cleidocranial dysostosis or Gardner's syndrome. This article aims to discuss a case of sequential formation of supernumerary teeth with no other associated disease or syndrome. A 17-year-old Iranian male with 8 impacted supernumerary teeth was referred to the department of pediatric dental clinic at Shahid Beheshti Medical University in Tehran with a history of several impacted unerupted teeth. Repeated and periodical clinical and radiographic examinations revealed newly formed teeth buds in unusual dental ages. All extra teeth were associated with generalized enamel hypoplasia to some degree on their relative permanent adjacent teeth. The patient did not have any record of a systemic disease or any syndromic condition to relate his dental problem to. This rare condition involved repeated and continued formation of extra teeth out of the normal numbers and dental age evident in serial radiographs

Effect of an Informative Leaflet on Knowledge Level of Mothers Regarding Traumatic Dental Injuries

Objectives: The present study aimed to assess the level of knowledge regarding traumatic dental injuries (TDIs) among mothers and evaluate the efficacy of a simple educational leaflet, as an informative tool, to raise their awareness in this respect. Methods: A total of 150 mothers with their children receiving dental care were included in this study and assigned to two groups of intervention and control. Before the intervention, a questionnaire was distributed among all the recruited mothers (time 0). After its completion, an informative leaflet with basic first aid information regarding what to do in case of TDIs was given to the mothers in the intervention group and their knowledge level was examined immediately after reading the leaflet (time 1). The knowledge of both groups was evaluated again after 3 months (time 2). The data were analyzed by SPSS version 21. Results: The mean knowledge score was 6.53 out of 10 at baseline. A significant increase in knowledge score was noted in the intervention group (9.20) at time 1 (P&lt;0.001). The knowledge score improved in both the intervention (8.57) and control groups (7.61) after 3 months (P&lt; 0.001). The intervention group had significantly higher score than the control group at time 2 (P&lt; 0.001).&nbsp; Conclusion: The informative leaflet enhanced the knowledge level of mothers regarding TDIs. Use of leaflets is suggested as an effective tool to inform mothers about the management of TDIs

Oral Melatonin Versus Midazolam as Premedication for Intravenous Sedation in Pediatric Dental Patients

Objectives: This study aimed to evaluate the effect of oral melatonin and oral midazolam as premedication for intravenous (IV) sedation of pediatric dental patients. Materials and Methods: This crossover, double-blind randomized clinical trial was conducted on 23 uncooperative 2-6-year-olds with definitely negative behaviors according to the Frankl's scale. Each child served as their own control. The children were randomly divided into two groups: group I received 0.5mg/kg of oral melatonin one hour before IV sedation, while group II received 0.5mg/kg of oral midazolam 30 minutes before IV sedation on their first visit. Every child received the other premedication on their second visit. The degree of sedation was judged according to the Houpt scale. Physiologic parameters including blood pressure (PB), heart rate (HR), and blood oxygen saturation (SpO2) and side effects including dizziness, nausea, vomiting, and sleepiness were assessed. The parents' and the operator's satisfaction rates were scored. Data were analyzed using paired t-test and Wilcoxon signed-rank test. Results: There were significant differences in sedation scores between the two sessions (P0.05). Nausea and vomiting were more common during the first two hours in the midazolam group (P=0.002). Tremors were more common in the melatonin group (P=0.013). Dizziness was more evident when melatonin was used (P<0.001). The clinician and the parents were more satisfied with the results of midazolam intake (P<0.05). Conclusions: Premedication with oral midazolam in pediatric patients is superior to that with melatonin with a higher parents' and operator's satisfaction.  

Comparison of nitrous oxide/midazolam and nitrous oxide/promethazine for pediatric dental sedation: A randomized, cross-over, clinical trial

Background: This study compared the safety and efficacy of nitrous oxide (N2O)/midazolam and N2O/promethazine for dental treatment of uncooperative children. Materials and Methods: In this randomized, cross-over, clinical trial investigation Eighteen healthy uncooperative children with a pair of similar teeth requiring the same treatment were included.Combination of N2O/midazolam was given in one visit, where N2O/promethazine was administrated in the other appointment for each patient in a cross-over manner. Oxygen saturation and heart rate as well as behavior parameters according to Houpt behavior scales were recorded. Postoperatively, patients' anxiety and parents' satisfaction were assessed by visual analog score and a questionnaire, respectively. Data were analyzed using Wilcoxon' s signed rank test and Paired t-tests with a P value set at 0.05. Results: Physiologic parameters were within normal limit in both groups. Children in midazolam group were significantly deeper sedated compared to other groups. In the first phase, children sedated with midazolam behaved superiorly in comparison to promethazine, while there was no difference at the final phase of the treatment between the two groups. Conclusion: Both of the drug combinations resulted in acceptable, efficient, and safe sedation outcomes