The Effect of Ultrasonic Post Instrumentation on Root Surface Temperature

Removal of broken abutment screws using ultrasonic tip - a heat development in-vitro study

BACKGROUND

Dental implants can cause complications, including the loosening of the abutment screw or fracture. However, there is no standardized technique for removing broken abutment screws. This necessitates further research.

OBJECTIVE

This study aimed to measure heat generation during screw removal to better understand its implications for dental implant procedures.

MATERIAL AND METHODS

The experimental setup involved using synthetic bone blocks and titanium implants. An ultrasonically operated instrument tip was utilized for screw removal. Infrared thermometry was employed for accurate temperature measurement, considering factors such as emissivity and distance. Statistical analysis using linear regression and ANOVA was conducted.

RESULTS

The findings revealed an initial rapid temperature increase during the removal process, followed by a gradual decrease. The regression model demonstrated a strong correlation between time and temperature, indicating the heat generation pattern.

CONCLUSION

Heat generation during screw removal poses risks such as tissue damage and integration issues. Clinicians should minimize heat risks through an intermittent approach. The lack of a standardized technique requires further research and caution. Understanding the generated heat optimizes implant procedures.

Removal capability, implant-abutment connection damage and thermal effect using ultrasonic and drilling techniques for the extraction of fractured abutment screws: an in vitro study

The aim of this work was to analyze and compare the removal capability, conical internal hex implant-abutment connection damage and thermal effect using ultrasonic and drilling techniques for the extraction of fractured abutment screws. Twenty abutment screws were randomly fractured into twenty dental implants and randomly extracted using the following removal techniques: Group A: drilling technique without irrigation (n = 10) (DT) and Group B: ultrasonic technique without irrigation (n = 10) (UT). The dental implants were submitted to a preoperative and postoperative micro-computed tomography (micro-CT) scan to obtain a Standard Tessellation Language (STL) digital file that determined the wear comparison by morphometry. Moreover, the thermographic effects generated by the DT and UT removal techniques were registered using a thermographic digital camera. Comparative analysis was performed by comparing the volumetric differences (mm3) between preoperative and postoperative micro-CT scans and thermographic results (°C) using the Student t test. The DT extracted 8/10 and the US 9/10 abutment screws. The pairwise comparison revealed statistically significant differences between the volumetric differences of postoperative and preoperative micro-CT scans of the DT (− 0.09 ± − 0.02mm3) and UT (− 0.93 ± − 0.32mm3) study groups (p = 0.0042); in addition, the pairwise comparison revealed statistically significant differences between the thermographic values of the DT (38.12 ± − 10.82 °C) and UT (78.52 ± 5.43 °C) study groups (p < 0.001). The drilling technique without irrigation provides a less removal capability, less conical internal hex implant-abutment connection damage and less thermal effect than ultrasonic technique for the extraction of fractured abutment screws; however, the ultrasonic technique resulted more effective for the extraction of fractured abutment screws.

Separated Instrument in Endodontics: Frequency, Treatment and Prognosis

Instrument separation during endodontic therapy is a frequent accident with rotary instruments being more likely to separate than manual ones. The treatment of cases with a separated instrument can be either conservative or surgical. A conservative approach involves the following treatment choices: a) bypass of the fragment, b) removal of the fragment, c) instrumentation and obturation coronally to the fragment. Concerning the removal of a separated instrument, a variety of techniques and systems have been developed. Ultrasonics, in combination with the operative microscope constitute the most effective and reliable tools for removing a separated endodontic instrument from a root canal. The likelihood of successful removal depends on: the level of separation (coronal, middle or apical third); location in relation to the root canal curvature; the type of separated instrument; its length; the degree of canal curvature and the tooth type. Several complications may occur during the management of a separated instrument: separation of the ultrasonic tip or file used for bypassing or removing the instrument; further separation of the fragment; perforation; ledge; extrusion of the file into periapical tissues; tooth weakening due to dentin removal, as well as excessive temperature rise in periodontal tissues. Prognosis for a tooth retaining a separated instrument depends on the presence of a periapical lesion, the microbial load of the root canal during the time of separation and the quality of the obturation.

Temperature rise during removal of fractured components out of the implant body: an in vitro study comparing two ultrasonic devices and five implant types

BACKGROUND

Ultrasonic instrumentation under magnification may facilitate mobilization of screw remnants but may induce heat trauma to surrounding bone. An increase of 5°C is considered detrimental to osseointegration. The objective of this investigation was to examine the rise in temperature of the outer implant body after 30 s of ultrasonic instrumentation to the inner part, in relation to implant type, type of ultrasonic equipment, and the use of coolants in vitro.

METHODS

Two ultrasonic devices (Satelec Suprasson T Max and Electro Medical Systems (EMS) miniMaster) were used on five different implant types that were provided with a thermo couple (Astra 3.5 mm, bone level Regular CrossFit (RC) 4.1 mm, bone level Narrow CrossFit (NC) 3.3 mm, Straumann tissue level regular body regular neck 3.3 mm, and Straumann tissue level wide body regular neck 4.8 mm), either with or without cooling during 30 s. Temperature rise at this point in time is the primary outcome measure. In addition, the mean maximum rise in temperature (all implants combined) was assessed and statistically compared among devices, implant systems, and cooling mode (independent t-tests, ANOVA, and post hoc analysis).

RESULTS

The Satelec device without cooling induces the highest temperature change of up to 13°C, particularly in both bone level implants (p < 0.05) but appears safe for approximately 10 s of continuous instrumentation, after which a cooling down period is rational. Cooling is effective for both devices. However, when the Satelec device is used with coolant for a longer period of time, a rise in temperature must be anticipated after cessation of instrumentation, and post-operational cooling is advised.

CONCLUSIONS

The in vitro setup used in this experiment implies that care should be taken when translating the observations to clinical recommendations, but it is carefully suggested that the EMS device causes limited rise in temperature, even without coolant.

Thermal irritation of teeth during dental treatment procedures

While it is reasonably well known that certain dental procedures increase the temperature of the tooth's surface, of greater interest is their potential damaging effect on the pulp and tooth-supporting tissues. Previous studies have investigated the responses of the pulp, periodontal ligament, and alveolar bone to thermal irritation and the temperature at which thermal damage is initiated. There are also many in vitro studies that have measured the temperature increase of the pulp and tooth-supporting tissues during restorative and endodontic procedures. This review article provides an overview of studies measuring temperature increases in tooth structures during several restorative and endodontic procedures, and proposes clinical guidelines for reducing potential thermal hazards to the pulp and supporting tissues.

Infrared thermographic comparison of temperature increases on the root surface during dowel space preparations using circular versus oval fiber dowel systems

PURPOSE

The purpose was to evaluate temperature increases during dowel space preparations with oval and circular fiber dowel systems.

MATERIALS AND METHODS

This study included 42 single-rooted human mandibular premolars. Roots were scanned with cone-beam computerized tomography (CBCT) to determine the ovoid root canal morphology. Root canals were treated with Ni-Ti rotary instruments and obturated. A second CBCT was taken to determine the thinnest dentin thickness of each root. Roots were randomly divided into two groups (n = 21) according to the fiber dowel system used: group 1, circular fiber dowel system (D.T. Light-Post); group 2, oval fiber dowel system (Ellipson Post). Dowel spaces were prepared using a circular fiber dowel drill and a diamond-coated ultrasonic tip with an oval section under water cooling until 9 mm dowel spaces were obtained. Temperature changes were recorded from the thinnest root surfaces using a FLIR E60 thermal imaging camera.

RESULTS

Temperature increases were significantly greater with the circular fiber dowel system than with the oval fiber dowel system (p < 0.05).

CONCLUSIONS

Although both dowel systems generated high temperature increases on root surfaces, the relatively lower temperature increase associated with the use of oval fiber dowels in ovoid canals makes it preferable to the use of circular fiber dowels.

Effect of different water flows on root surface temperature during ultrasonic removal of posts

OBJECTIVE

This in vitro study evaluated rises in temperature on the outer root surface of human incisors during ultrasonic post removal with different water flows.

STUDY DESIGN

Thirty-six extracted teeth (12 maxillary central incisors, 12 maxillary lateral incisors, and 12 mandibular incisors) were used. After root canal preparation, the teeth were obturated, and prefabricated posts were cemented into the prepared spaces. Posts were ultrasonically instrumented dry and with irrigation at 20 mL/min and 40 mL/min. Temperature changes on the entire mesial outer surfaces of the roots were measured at 10-second intervals using an infrared thermal imaging camera.

RESULTS

Increases in root surface temperature were significantly lower when posts were instrumented with 40 mL/min water irrigation compared with dry vibration and 20 mL/min irrigation, which also significantly differed from each other. Statistical analysis among tooth groups showed differences in the mean temperature rise of maxillary central incisors and maxillary lateral incisors compared with mandibular incisors when posts were instrumented dry or with 20 mL/min irrigation. There were no significant differences in mean temperature rises between the studied groups when 40 mL/min irrigation was used.

CONCLUSIONS

Water cooling during ultrasonic post instrumentation significantly reduced temperature increases on the outer root surface; however, the intensity of the cooling was also important. Our results suggest that copious water irrigation during post removal is an effective method to protect the root's surrounding tissue.

Influence of water cooling on root surface temperature generated during post space preparation

INTRODUCTION

This in vitro study evaluated the temperature increases on the root surface of teeth during preparation of post space with and without water cooling.

METHODS

Thirty premolar teeth with a single canal were used. After root canal obturation, the teeth were divided into 2 groups, and post spaces were prepared by using a drill without cooling (dry group) and with water irrigation of 25 mL/min(-1) (wet group). Temperatures were measured on the entire root surface by using a thermal imaging camera.

RESULTS

Root surface temperature increases were significantly lower when post spaces were created with water cooling compared with dry post preparation (P < .0001 for root canal filling removal and P < .0001 for post space preparation). In both groups, significantly higher temperatures were recorded during the post space preparation than during the filling removal (P < .001 for nonirrigated teeth and P < .001 for irrigated teeth).

CONCLUSIONS

Irrigation during post space preparation significantly influenced the outer root surface temperature. The risk of irreversible injury to the root surrounding tissues is potentially minimized when post space is prepared by using water cooling.

Insufficient evidence for the effectiveness of ultrasonic instrumentation for root canal treatment

DATA SOURCES

Relevant studies were sourced using the Cochrane Oral Health Group Trials Register, Cochrane Central Register of Controlled Trials (CENTRAL), Medline and Embase. The reference lists of relevant articles were searched and personal databases of trial reports used, in an attempt to locate additional published and unpublished trials. No language restriction was applied.

STUDY SELECTION

Randomised controlled trials (RCT) were selected that involved people of age >/=18 years with single and multiple permanent teeth with a completely formed apex and no evidence of internal resorption, who required root canal treatment. Patients undertaking retreatment of a tooth were excluded.

DATA EXTRACTION AND SYNTHESIS

Screening of eligible studies was conducted in duplicate and independently by two review authors. Results were to be expressed as fixed- or random-effects models using mean differences for continuous outcomes and risk ratios for dichotomous outcomes with 95% confidence intervals. Heterogeneity was to be investigated including both clinical and methodological factors.

RESULTS

No eligible RCT could be found.

CONCLUSIONS

This review illustrates how there are no published or ongoing RCT relevant to this review question and that there is currently insufficient evidence regarding the effectiveness of ultrasonic instrumentation used alone for orthograde root canal treatment. Future RCT might focus more closely on evaluating the effectiveness of hand instrumentation compared with hand instrumentation and adjunctive ultrasonic instrumentation.