Browsing by Author "Patel, Zaheed"

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    Heat transmission along the surface of dental implant
    (University of the Western Cape, 2009) Patel, Zaheed; Geerts, Greta A. V. M.; Dept. of Restorative Dentistry; Faculty of Dentistry
    Objectives: Temperature changes along an implant body have not been widely studied. The objectives of this in vitro study were (i) to establish if the temperature of the abutment influences the temperature of the implant surface, (ii) to establish the temperature transmission from abutment to implant body, and (iii) to establish for what abutment temperature the critical time/temperature threshold of 47oC for 1 minute at implant level is reached. Materials and method: Eight K-type thermocouples were attached to an abutment/implant configuration, mounted in a thermostatically controlled environment. The abutment was exposed to hot water. The temperature at each thermocouple along the implant was logged over a maximum period of 10 minutes using appropriate software. The test was repeated 200 times. A logistic regression model was used for the analysis of the time/temperature databases. Results: There was a positive correlation between the temperatures of the implant and its abutment, albeit with a time delay. Critical threshold values for bone necrosis were reached. The effective dose 50 was estimated at 62.3oC (95% confidence interval estimate): for an abutment temperature of 62.3oC there is a 50% chance that 47oC for 1 minute at implant level is reached. Conclusion: The results of this in vitro study support the hypothesis that abutment temperature is transmitted to a dental implant body. Results of in vitro studies should be interpreted with caution. However, clinicians should be aware of temperature changes along implants and the potential risk associated with this.
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    Temperature changes along a dental implant
    (Quintessence Publishing, 2011) Geerts, Greta; Patel, Zaheed
    AIMS: The aims of this in vitro study were to analyse temperature changes along the surface of a dental implant and to establish the abutment temperature that could cause the critical 47ºC/1min threshold at implant level. METHODS: Eight thermocouples were attached at 1 mm intervals to an abutment/implant configuration. The model consisted of 2 compartments in a thermostatically controlled environment. The upper compartment represented the oral cavity with the abutment, which was exposed to 20ml of hot water. The temperature at each thermocouple was logged over a period of 10 minutes. A Spearmans Rank correlation test and logistic regression model were used for the statistical analysis of the time/temperature databases and the estimation of the ‘effective dose 50’ for the abutment (95% confidence interval). RESULTS: For 53 test series, the abutment temperature ranged from 52.80ºC to 71.72ºC. There was a positive correlation between the maximum temperature at implant level and the temperature of the abutment. The 47ºC/1min threshold was reached 31 times at the most cervical implant level and decreased in frequency further away from the heat source (14, 6, 3, 1 and 1 times resp.) The ED50 was estimated at 62.3ºC. This means that for an abutment temperature of 62.3ºC there was a 50% chance that 47ºC for 1 minute at implant level would be reached. CONCLUSION: This in vitro study supports the hypothesis that abutment temperature is transmitted to an implant. Although results of in vitro studies should be interpreted with caution, clinicians should be aware of temperature changes along implants and the potential risk associated with it.