Temperature threshold levels for heat-induced bone tissue injury: a vital-microscopic study in the rabbit

Comparison of the thermal bone damage done by the oscillating saw and bone mill burr during total knee arthroplasty

Background

Thermal osteonecrosis from bone cutting during total knee arthroplasty (TKA) may cause aseptic implant loosening. The study compares thermal bone injury from oscillating saw (CTKA) and bone milling burr treatments (RATKA).

Method

A prospective study comparing thermal necrosis during CTKA and RATKA was performed. The sample size (n = 36) was determined with 18 patients per group, assuming a 15 % relative increase in thermal necrosis with RATKA, with statistical thresholds set at α = 5 % and β = 10 %. The upper tibia cut surface was analyzed, with histological sections examined from 20 randomly selected fields. Thermal necrosis was evaluated by determining the proportion of non-viable cells relative to viable ones and measuring the depth from the cut bone surface at which the first intact osteocyte was observed. Statistical analysis was conducted using appropriate comparative tests, including Chi-square and t-tests, with significance determined at a threshold of p < 0.05.

Results

There was no significant variability in preoperative patient characteristics (gender, age, body mass index, diagnosis, range of motion, deformity and comorbidities) between CTKA (n = 18) and RATKA (n = 18) groups. The percentage of dead osteocytes at the resected surface in CTKA and RATKA were 40.3 % and 46.5 % respectively (p = 0.6309). The minimum depth where viable osteocytes were found was 25.5 ± 3.5 μmm and 27.1 ± 3.6 μmm in CTKA and RATKA respectively (p value = 0.091).

Conclusion

Conventional TKA and RATKA produce similar thermal effects on bone, with no significant difference in osteocyte viability. This indicates that both surgical methods are comparable regarding thermal impact on bone health.

Mechanical and thermal efficiency of a single drill system for bone-anchored hearing implants

PURPOSE

This study aimed to evaluate the mechanical performance, heat generation, bone distortion, and characteristics of bone chips generated during drilling using a novel one-step guided drill system (MONO) for installing the bone-anchored hearing system (BAHS). A comparison was made with an existing three-stage drill system (MIPS).

MATERIALS AND METHODS

Drill force and torque were measured during drilling in cow tibia at different feed rates. Compact artificial bone was utilized to determine temperature increases using thermocouples placed at specific positions around the osteotomy site during drilling with the two systems at different feed rates and levels of irrigation. The effects of drilling on osteotomy characteristics and the formation of bone fragments were evaluated through micro-CT, Raman spectroscopy, and histology.

RESULTS

Force and torque increased with the feed rate in both systems, whereas the total work required to perform the osteotomy significantly decreased as the feed rate increased. Compared to the three-stage MIPS system, the MONO system required less work for one-step osteotomy creation, generated equal or less heat, and exhibited greater tolerance for procedural deviations in irrigation and drilling sequence. Additionally, heat generation for both systems decreased when drilling at higher feed rates. Compositional changes within the osteotomy were primarily observed under reduced irrigation protocols, while no differences were identified in bone chips across drilling protocols.

CONCLUSION

Compared with a multistep conventional drilling procedure, MONO drilling is less affected by variations in the drilling protocol, particularly in flapless and blind procedures, resulting in safer and more efficient osteotomy creation. The MONO system demonstrated superior performance in terms of energy efficiency and temperature control.

Slicing through complexity: a systematic review assessing the efficacy and safety of water-jet dissection in neurosurgical procedures with technical suggestions

Dissection methods are variable, and surgeons select the appropriate method based on its safety, efficiency and applicability. The water-jet dissection technique is a promising method that has been applied in different surgeries. We try to highlight the possible neurosurgical applications and evaluate the safety and efficacy of this technique. We conducted a comprehensive systematic review search in the following electronic databases: PubMed, Embase, Web of Science, and Cochrane Library from inception to January 2025. A qualitative synthesis was performed to summarize the findings on the efficacy, safety, and technical challenges of water-jet dissection in neurosurgery. A total of 401 patients were included in our review. Nine studies (351 patients) used the conventional water jet dissection technique, and 4 studies (50 patients) used the laser-based technique. Conventional water jet dissection has been employed in 183 cases involving glioma (52.1%), 32 cases involving meningioma (9.1%), 75 cases for other tumors (21.3%), 46 cases in epilepsy surgery (13.1%). Laser-based techniques have been less frequently used, with 10 cases reported for meningioma (12.3%), 25 cases for other tumors (30.8%), and 46 cases for vascular surgeries (56.7%). For conventional water-jet dissection, complications were observed, with vessel injury and wound infection/brain abscess occurring in 10 cases each (2.8%), post-operative edema in 3 cases (0.8%), air embolism in 1 case (0.3%), failed dissection in 13 cases (3.7%), other complications in 10 cases (2.8%), and no reported thermal injury. Only 3 (6%) complications were observed in the pulsed-based water-jet dissection technique. Water-jet dissection is a promising tool that can be used safely in neurosurgical interventions. However, precautions should be taken to minimize its potential risks and ensure optimal patient outcomes. Robust research in the form of randomized clinical trials and prospective case series should be recruited for further evaluation of this tool.

Effect of Ti6Al4V Alloy Surface and Porosity on Bone Osseointegration: In Vivo Pilot Study in Rabbits

Unmodified Ti6Al4V can osseointegrate, but sometimes this capacity needs to be improved. This study aimed to see how much porosity improves osseointegration in a Ti6Al4V implant. Three types of Ti6Al4V cylindrical-shaped implants (13.00 mm length × 5.00 mm diameter) were evaluated: solid sandblasted acid-etched, sintered, and porous 3D-printed (681.00 µm average pore size). Fifteen 20-week-old nullipara female parasite-free New Zealand California white rabbits were used, employing the femoral condyle defect model and undertaking µ-CT analysis and pull-out testing eight weeks later. On µ-CT densitometric analysis, the solid sandblasted rod showed the highest new bone growth around the implant. Bone growth was higher inside the implants for the porous 3D-printed (54.00 ± 5.00 mm3) than for the sintered (1.00 ± 0.05 mm3) and zero for the sandblasted implants. In the pull-out test, there were no statistically significant differences in the ANOVA analysis between the sintered (900.00 N ± 310.00 N) and porous 3D-printed (700.00 N ± 220.00 N) implants. Such differences did exist between the sandblasted material (220.00 N ± 50.00 N) and the two other materials (sintered p 0.002, porous p 0.034). The porous 3D-printed and sintered implant pull-out strength were significantly better than that of the solid rod sandblasted implant. Still, there were no statistically significant differences between the first two.

Evaluation of heated sodium hypochlorite's effect on the accuracy of contemporary electronic apex locators: an in vitro study

BACKGROUND

Accurate determination of the working length (WL) is essential for successful root canal therapy. Although electronic apex locators (EALs) are widely used for this purpose, the impact of irrigant temperature on their precision remains poorly understood. Therefore, in this study, we investigated the effect of variations in sodium hypochlorite (NaOCl) temperature on the performance of modern EALs, with particular emphasis on the recently introduced EAL, Ai-Pex.

METHODS

Twenty extracted human teeth were embedded in alginate to simulate clinical conditions. WL was measured using four EALs (Root ZX Mini, Propex Pixi, Raypex 6, and Ai-Pex) under three NaOCl temperature conditions: 19.4 °C (± 1.5 °C), 36 °C, and 70 °C. A dental operating microscope was used to determine the actual working length (AWL). Deviations between electronic and AWLs were recorded, and statistical analyses were conducted using repeated-measures analysis of variance (ANOVA) and chi-square tests.

RESULTS

All EALs exhibited high accuracy, with deviations within ± 0.5 mm of AWL across all NaOCl temperature conditions (p > 0.05). Ai-Pex achieved 95% accuracy at room and body temperatures and 100% accuracy at 70 °C. Similarly, Root ZX Mini, Propex Pixi, and Raypex 6 demonstrated consistent performance, with no statistically significant differences in accuracy across temperature groups.

CONCLUSIONS

This study confirms that variations in NaOCl temperature do not significantly impact the accuracy of EALs in determining the WL for root canal therapy. These findings underscore the reliability of contemporary EALs under different clinical conditions, including the newly evaluated Ai-Pex. Further, in vivo studies are necessary to validate these results.

Real-Time Analysis of Changes in Internal and External Root Temperatures Using Different Systems for Activating the Irrigation Solution

Introduction: There is a concern regarding the heating transfer to the periodontal tissues after irrigating solution activation. Therefore, this study analyzed the real-time changes in internal and external root temperatures using different systems for activating the irrigant. Methods: Two single-rooted mandibular premolars were chemomechanically prepared. Three orifices were drilled on the root surface at 3, 6, and 9 mm from the apical foramen with a spherical diamond bur. In one tooth, drilling was restricted to the cementum. In another tooth, drilling was performed close to canal dentin. Thermocouple sensors were coupled to the orifices and fixed with resin for temperature measurement. Irrigation was performed with 2.5% NaOCl at 25°C or 45°C. The irrigant was activated for 20-, 30- and 60 s using 3 different systems: passive ultrasonic irrigation (PUI), Ultra X (UX), and endoactivator (EA). For each initial irrigant temperature, time, and activation system, the tests were repeated 8 times, resulting in a total of 96 evaluations for the external and internal root temperatures (n = 48 for each). Results: Data was statistically analyzed with a multilevel linear regression model and intraclass correlation coefficients (ICCs) were calculated. Then, four-way ANOVA with Bonferroni's post hoc tests performed intergroup and intragroup comparisons. EA promoted lower temperature increase than PUI and UX (p  < 0.05). PUI and UX induced similar internal and external temperature changes when irrigated with NaOCl at 25°C.. Conclusion: The initial temperatures (25°C or 45°C) and the activation systems of the irrigant had influence on the internal and external radicular temperatures. The activation period had little influence on root temperature changes, which may be deemed clinically safe.

Properties of Tungsten Carbide Rings When Compressed to Failure or Cut with a Diamond Grinding Bit: A Biomechanical Study

BACKGROUND

Tungsten carbide rings are increasingly popular modern jewelry items. Tungsten carbide is an extremely dense, hard metal. Previously described methods to remove tungsten carbide rings include using locking pliers to compress the ring or cutting the ring with a high-speed dental drill.

METHODS

A universal mechanical testing system (MTS) machine was used to diametrically compress tungsten carbide rings 9 mm in length and 2.4 mm in thickness with a 23.4-mm outer diameter and a 21.0-mm inner diameter while measuring the force required to fracture the rings. A computer numerical control (CNC) machine was used to cut tungsten carbide rings with a diamond grinding bit with and without a flow of normal saline solution. An infrared thermal camera was used to record the temperature at the site of contact between the ring and the grinding bit and at a site one-quarter of the circumference along the ring.

RESULTS

A mean force with 95% confidence interval of 3.7 ± 1.2 kN was required to fracture the tungsten carbide rings via diametral compression (p = 0.05). The rings failed at a mean displacement with 95% confidence interval of 0.32 ± 0.13 mm (p = 0.05). The maximum temperature observed at the site of contact between the ring and grinding bit averaged 160.2°C including cases with and without coolant. The time to reach maximum temperature and the duration of maximum temperature differed significantly between the cases with and without coolant (p = 0.0007 and p = 0.0108, respectively).

CONCLUSIONS

Tungsten carbide rings fractured with minimal displacement using a small amount of force via diametral compression. The brittle fracture pattern of the rings produced minimal comminution. Tungsten carbide rings reached extreme temperatures when cut with a high-speed diamond grinding bit despite cooling with normal saline solution.

CLINICAL RELEVANCE

Previously documented methods to remove a tungsten carbide ring include breaking the ring by compressing it with pliers or cutting it off with a high-speed dental drill. Clinicians should be aware of potential complications of current methods to remove tungsten carbide rings.

Orthodontic Ceramic Bracket Removal Using Lasers: A Systematic Review

OBJECTIVE

The aim of this systematic review was to evaluate the effectiveness and safety of various laser systems for debonding ceramic orthodontic brackets compared to conventional mechanical removal methods. The primary outcomes assessed included enamel damage, pulp temperature changes, adhesive remnant index (ARI), and shear bond strength (SBS).

MATERIALS AND METHODS

A systematic search was conducted in November 2024 across the PubMed, Scopus, and Web of Science (WoS) databases following PRISMA guidelines. The initial search yielded 453 records, of which 41 studies met the inclusion criteria for qualitative and quantitative analysis. The risk of bias was assessed using a standardized scoring system, and only studies with accessible full texts were included.

RESULTS

The review highlighted significant heterogeneity in laser parameters, measurement protocols, and study methodologies. Among the evaluated lasers, CO2 and Er:YAG were the most frequently studied and demonstrated high efficacy in debonding ceramic brackets while maintaining enamel integrity. Sixteen studies assessing SBS reported a reduction from baseline values of 13-23 MPa to clinically acceptable ranges of 7-12 MPa following laser application. ARI was analyzed in 25 studies, with laser-treated groups exhibiting higher scores (2-3), indicating safer debonding with more adhesive remaining on the tooth surface, thereby reducing enamel damage. Pulpal temperature increases were examined in 23 studies, revealing that most laser types, when used within optimal parameters, did not exceed the 5.5 °C threshold considered safe for pulpal health. However, diode and Tm:YAP lasers showed potential risks of overheating in some studies.

CONCLUSIONS

Laser-assisted debonding of ceramic orthodontic brackets is an effective and safe technique when applied with appropriate laser parameters. CO2 and Er:YAG lasers were the most effective in reducing SBS while preserving enamel integrity. However, variations in laser settings, study methodologies, and the predominance of in vitro studies limit the ability to establish standardized clinical guidelines. Further randomized controlled trials (RCTs) are necessary to develop evidence-based protocols for safe and efficient laser-assisted bracket removal in orthodontic practice.

Fibre post removal using ultrasonic tips: A comparative in vitro study using different protocols

This study evaluated the glass fibre post (GFP) removal using three different protocols with ultrasonic tips. Thirty-six extracted single-rooted teeth were endodontically treated and cemented with a 10-mm GFP. Three protocols were used for GFP removal: 20 s activated with cooling, 20 s activated without cooling and 40 s activated without cooling. The removal time and temperature increase on the external root surface were recorded. The amount of residual material and the volume of dentin loss were assessed using micro-computed tomography. Data were analysed using ANOVA with a 5% significance level. The removal time and the amount of residual material were not affected by the protocol. There was no difference in temperature increase between the 20-s groups. The 40s activated without cooling produced the highest temperatures, especially in the apical region, and greater dentin loss. It is not advisable to use the ultrasonic insert continuously for more than 20 s.

Impact of drill bit wear on temperature increase in dental implant osteotomy: an in vitro study

OBJECTIVES

Dental implant surgery relies extensively on bone drilling, a critical procedure with intrinsic challenges. Drill bits show significant wear and are frequently utilized beyond the manufacturer's recommended limits. Such practices can result in adverse effects, including friction and temperature rise in the surrounding bone area during interventions, with an increased risk of necrosis that can compromise the dental implant osseointegration. This study aimed to compare the quality of osteotomy obtained from two different protocols to determine a possible correlation between the drilling temperature and the tool wear and to evaluate their impact on potential health damage.

MATERIALS AND METHODS

Experimental evaluations were conducted using synthetic bone that reproduced human bone characteristics. The drilling phase involved real-time temperature acquisition and scanning electron microscopy analysis of tool wear evolution. After the operation, actual hole size and geometry were characterized using a coordinate measuring machine, and temperatures and torques were measured during the subsequent implantation phase.

RESULTS

The findings revealed a direct correlation between tool wear and the temperature rise during the drilling phase, while a lower correlation was found with the hole profile geometry variation. The implantation phase demonstrated temperature and torque values within acceptable ranges.

CONCLUSIONS

This study highlights the importance of adhering to proper tool maintenance and replacement protocols. By following recommended guidelines, practitioners can minimize adverse effects and enhance the success of dental implant procedures.

Ablative and Expansive Protocols for Bone Osteotomy in Rabbits

Background: Cortical and marrow bone layer have different histomorphometric features. The traditional implant insertion technique provides for fixture stabilization through the cortical area. However, this approach has been found to result in an overstress of this bone layer, which may lead to resorption. Therefore, the aim of this study was to evaluate bone healing by applying two different implant site preparation protocols across various bone densities. Materials and Methods: One implant was placed in each femur and tibia of the rabbits (four implants per animal), using two distinct site preparation methods: drilling alone or drilling followed by osteotomes (funnel technique). Three regions around the implant were evaluated: cervical, marrow, and apical. The study included 12 rabbits, divided into two groups of 6 animals each, which were euthanized at 3 and 6 weeks, respectively (n = 6 per group). Results: In the cervical region of both femur and tibia, no marginal bone resorption could be detected. Similar BIC% (bone-to-implant contact percentages) were observed for funnel and drill sites after 3 weeks and 6 weeks of healing. Differences, though not statistically significant, ranged between 2.8% and 4.7%. However, higher BIC% values were observed in the femora compared to the tibia in both periods. Conclusions: No marginal bone loss was observed in both techniques. No statistically significant differences in bone resorption or bone-to-implant contact around the implant collar were observed when comparing two implant site preparation protocols across various bone densities. The use of osteotome did not influence the healing in the marrow region.

External Root Temperature and Its Relationship With Dentin Thickness During Gutta-Percha Removal Procedures With Ultrasound. An Ex Vivo Study

INTRODUCTION

This study aims to evaluate the temperature rise on the external root surface during gutta-percha removal with 2 types of ultrasonic tips, and its relationship with the root dentin thickness.

METHODS

A total of 56 single-rooted teeth were prepared for gutta-percha removal procedures, conducted for 40 seconds using 2 types of ultrasonic tips at depths of 6 mm and 11 mm. The temperature generated was measured using a type K thermocouple at 3 measurement points. Nonparametric Wilcoxon test was used, and the correlation between thickness and temperature rise was evaluated with Spearman correlation test.

RESULTS

The temperature rise occurred in all groups, reaching maximum values of 21.0°C (mean = 14.6) with Clearsonic and 11.3°C (mean = 4.2) in the Clearsonic Black group, recorded at a 1-mm depth at 40 seconds (P < .05). At 20 seconds, the Clearsonic produced an increase ranging from 10.5°C and 12.9°C in 25% of teeth. No significant differences were observed between the 2 types of ultrasonic tips at an 11-mm depth, across all time intervals and measurement points. Spearman's coefficient showed significant correlations with Clearsonic use at 20 seconds. Significant correlations with Clearsonic Black were observed at 20 and 40 seconds at point T1.

CONCLUSIONS

The Clearsonic Black generates a smaller temperature increase at a depth of 6 mm compared to the Clearsonic and within a time not exceeding 20 seconds (P < .05). There is a partial correlation between temperature increase and dentin thickness.

Parameter Optimization, Morphological and Histological Characteristics of Accurate Bone Ablation by Femtosecond Laser: An In Vitro Study

The use of femtosecond laser for bone ablation has been demonstrated in numerous studies; however, the clinical application requires further optimization to meet safety, accuracy, and efficiency standards. This study aims to optimize the energy density parameter of a robot-controlled femtosecond laser surgical system for bone ablation by assessing temperature changes, ablation efficiency, and ablation effects. Furthermore, the morphological and histological characteristics of bone tissue were compared with those of conventional mechanical methods. The results indicated that a laser energy density of 1.05 J/cm2 was optimal for bone ablation, maintaining the bone surface temperature below 47 °C and achieving an ablation efficiency of 0.145 mm3/s. The deviations in cavity diameters were significantly smaller for the laser group (6.58 ± 18.09 μm) compared to the bur group (80.09 ± 45.45 μm, p < 0.001, N = 5 per group). Femtosecond laser ablation produced cleaner cavity margins with minimal bone debris accumulation. Additionally, the adjacent Volkmann and Haversian canals retained their normal morphology, indicating limited mechanical and thermal damage to the bone tissue. The robot-controlled femtosecond laser system demonstrated the potential for achieving safe, accurate, efficient, and clean bone ablation, offering promising prospects for clinical applications.

In-vitro investigation of bone temperature changes in osteotomies performed with different brands of implant burs

The aim of this study was to investigate in-vitro the temperature changes occurring in the bone during drilling with implant drills manufactured by different companies. Bone blocks obtained from fresh bovine ribs were used in the study. Bone blocks were drilled with drills manufactured by Ankylos, Astra Tech, Nobel Biocare, Bredent and Straumann implant brands at an ambient temperature of 30 ± 2° C under a constant pressure of 2 kg. Two K-type thermocouple sensors were placed on the bone blocks at 5th and 10th mm depths and the temperature changes were measured at a distance of 1 mm from the implant drill. In the study, working models were created under different conditions for implant socket preparation. In group 1, the first time drills were used at 150 rpm without irrigation, in group 2, the first time drills were used at 1200 rpm with 40 ml/min irrigation, in group 3, the 30th time drills were used at 150 rpm without irrigation, and in group 4, the 30th time drills were used at 1200 rpm with 40 ml/min irrigation. All osteotomy procedures were performed with 3.5 ± 0.3 mm diameter burs for a period of 8 s and the temperature values obtained at equal time intervals were recorded. Repeated Measures and Kruskall Wallis-H tests were used for statistical analysis of the data. No significant difference was observed between the implant drills and the temperature changes in the bone during drilling (p < 0.05). None of the groups reached critical temperature values (47° C+) throughout the study. At the 5th and 10th mm depths, the temperature changes in the sensors used were close to each other. It was also calculated that although the average temperatures were close to each other in the non-irrigated and irrigated systems, the difference values obtained by subtracting the initial temperature were significantly higher in the non-irrigated systems. The results showed that implant drills did not cause significant temperature increases in bone blocks depending on the difference in manufacturers (Ankylos, Astra Tech, Nobel Biocare, Bredent, Straumann) and the number of uses. It was also concluded that irrigated and non-irrigated systems are safe as long as they are used under the recommended conditions.

Osseointegration in relation to drilling speed in the preparation of dental implants sites: A systematic review

STATEMENT OF PROBLEM

The drilling speed used for preparing dental implants may affect bone-implant contact (BIC), implant stability quotient (ISQ), and bone area fraction occupancy (BAFO). Different rotational speeds and the presence or absence of irrigation during site preparation have been investigated, but an established protocol for achieving the best osseointegration results is lacking.

PURPOSE

The purpose of this systematic review was to investigate the influence of drill rotational speed on bone drilling for dental implant placement and its relationship with osseointegration.

MATERIAL AND METHODS

This review included the preferred reporting items for systematic reviews and meta-analyses (PRISMA) and was registered in the international prospective register of systematic reviews (PROSPERO) database. Electronic searches were performed in the MEDLINE (PubMed), Scopus, Science Direct, and Embase databases. The risk of bias was analyzed by using the systematic review center for laboratory animal experimentation (SYRCLE).

RESULTS

A total of 1282 articles were found, and after removing duplicates and applying the eligibility criteria to in vivo articles on animals that addressed drilling speed and its relationship to osseointegration, 8 articles were selected for analysis. Of these, 5 articles showed no statistical differences, and 3 others showed significantly better osseointegration results by analyzing the parameters of BIC, BAFO, ISQs, and pull-out forces (PoFs). In all selected articles, high-speed drilling was performed with irrigation.

CONCLUSIONS

Although drilling speed seems to affect bone perforation, no definitive protocol was found in the literature consulted. The results vary depending on the combination of different factors, including bone type, irrigation, and drilling speed.

Antibacterial properties and biological activity of 3D-printed titanium alloy implants with a near-infrared photoresponsive surface

PURPOSE

SLM 3D printing technology is one of the most widely used implant-making technologies. However, the surfaces of the implants are relatively rough, and bacteria can easily adhere to them; increasing the risk of postoperative infection. Therefore, we prepared a near-infrared photoresponsive nano-TiO2 coating on the surface of an SLM 3D-printed titanium alloy sheet (Ti6Al4V) via a hydrothermal method to evaluate its antibacterial properties and biocompatibility.

METHODS

Using SLM technology, titanium alloy sheets were 3D printed, and a nano-TiO2 coating was prepared on its surface via a hydrothermal method to obtain Ti6Al4V@TiO2. The surface morphology, physicochemical properties, and photothermal response of the samples were observed. The Ti6Al4V groups and Ti6Al4V@TiO2 groups were cocultured with S. aureus and E. coli and exposed to 808 nm NIR light (0.8 W/cm2) and viable plate count experiments and live/dead bacterial staining were used to assess their in vitro antibacterial properties.

RESULTS

The hydrophilicity of the nano-TiO2 coating sample significantly improved and the sample exhibited an excellent photothermal response. The temperature reached 46.9± 0.32 °C after 15 min of irradiation with 808 nm NIR light (0.8 W/cm2). The Ti6Al4V group showed significant antibacterial properties after irradiation with 808 nm NIR light, and the Ti6Al4V@TiO2 group also had partial antibacterial ability without irradiation. After irradiation with 808 nm NIR light, the Ti6Al4V@TiO2 group showed the strongest antibacterial properties, reaching 90.11± 2.20% and 90.60± 1.08% against S. aureus and E. coli, respectively.

CONCLUSIONS

A nano-TiO2 coating prepared via a hydrothermal method produced synergistic antibacterial effects after NIR light irradiation.

Comparative Analysis of Temperature Changes with Preheated and Intracanal Heated Solutions and Ultrasonic Activation in Immature Teeth

INTRODUCTION

The aim of this study was to examine the temperature changes on root canal and root surface in immature teeth with thin dentinal walls when irrigation solutions are preheated or intracanal heated, as well as the additional effects of passive ultrasonic irrigation (PUI) on these temperature changes.

METHODS

Sixteen maxillary canine teeth were trimmed to a length of 20 mm and prepared to mimic immature teeth with an apical width of 1.3 mm by enlarging those using Gates Glidden burs. To measure temperatures inside the canal and on the root surface, one thermocouple was placed from the apex into the root canal, while the other thermocouple was positioned outside the root. Irrigation was performed by heating the irrigation solution with different methods (room temperature, preheated to 60°C, 5 sec intracanal heated, 20 sec intracanal heated), and PUI was applied after each method. Temperature changes occurring inside the root canal and on the root surface were recorded and subjected to statistical analysis.

RESULTS

Using the irrigation solution preheated and intracanal heated resulted in a significant increase in both intracanal and root surface temperatures compared to using at room temperature (P < .05). The application of PUI significantly increased the temperature of the irrigation solution only at room temperature group (P < .05). None of the applications caused an increase in temperature on the root surface exceeding 10°C.

CONCLUSIONS

Applying PUI to heated solutions does not significantly increase the temperature in heating methods, but it does prolong heat retention in the canal by slowing down the cooling process. Although using preheated solution for 20 seconds results in higher intracanal temperatures, it should be noted that the solution cools rapidly within the canal. Short-term heating applications, such as 5 seconds, repeated frequently, can help maintain the high temperature during activation.

Comparative analysis of bone healing in subcritical defects with air turbine and electric handpiece in a rat model

Rotatory devices are essential in clinical surgical practice, however, depending on the different systems available, their function can impact bone repair and postoperative responses on varying scales. This impact underscores the need to explore new techniques aiming to enhance bone repair. This study aimed to assess the immediate and delayed effects on bone healing in subcritical bone defects using both air turbine and an electric handpiece. For this purpose, 40 male Wistar rats were allocated into two groups. The Control Group (CG) had bone defect made using an air turbine device, while the Experimental Group (EG) had defects made using an electric handpiece. Ten animals were sacrificed for each time of evaluation. Bone neoformation, microstructure, and collagen organization were assessed ate 7, 15 and 30 days postoperative. Inflammatory profiling was conducted at 7 and 15 days. Immediate thermal osteonecrosis were evaluated after the use of rotary systems. Multivariate analysis was used to access statistical differences. The EG exhibited enhanced parameters of bone neoformation in all analyses, with statistical difference between 15 and 30 days (P = .0002) and in comparison with CG in 30 days (P = .0009). A reduced number of inflammatory cells and increased angiogenesis in the initial periods was seen in EG, corroborating the consistent values of collagen type 1 and a decrease of collagen type 3 over times. Immediate thermal osteonecrosis was statistically higher for the CG (P < .05), which showed adequate neoformation of subcritical defects but consistently lower values than those found in the EG. These data suggest that the electric handpiece demonstrated more bone repair area, proving to be an excellent alternative to surgical practice.

Piezosurgery in Third Molar Extractions: A Systematic Review

Background: The aim of this systematic review was to evaluate the clinical efficacy, benefits, and limitations of piezosurgery in tooth extractions compared to conventional methods. Piezosurgery has emerged as a minimally invasive alternative, promoting better preservation of soft tissues and bone structures. Understanding its impact on postoperative outcomes such as pain, swelling, trismus, and bone healing is critical for its application in oral surgery; Materials and Methods: We restricted our search to English-language articles published between 1 January 2004 and 28 August 2024, in PubMed, Scopus, and Web of Science. The Boolean search keywords "piezosurgery AND tooth extraction" were used. Results: A total of 983 articles were identified, and after duplicates were removed, 766 studies were screened. Following the application of inclusion and exclusion criteria, seven articles were selected for qualitative analysis. Conclusions: The literature suggests that piezosurgery offers advantages, such as reduced postoperative pain, swelling, and trismus, despite longer surgical times compared to conventional methods. While piezosurgery shows promise for improved patient comfort and soft tissue preservation, further research is required to validate its long-term impact on bone healing and regeneration.

Dental health concerns for patients suffering from facial, peri-oral burns, and inhalation injury: A persistent yet underappreciated challenge

Demographic data reveal a correlative relationship between facial burns and profoundly impaired dental health, while inhalation injury correlates with a high Periodontal Screening and Recording Index, both of which significantly reduce quality of life for the burn injury patient. Despite these facts, few if any burn centers surveyed in the U.S. or Germany enlist specialized services and well-defined follow-up protocols for patients who might well be at risk. Facial burns represent a severe injury, the consequence of which may tragically lead to significant and long lasting functional, esthetic, and psychological sequelae such as perioral scarring, deformity and microstomia. Inhalation injury from inhaled heated air, gas, and chemical exposure are well-known causes of early as well as late airway injury, morbidity, and death. Thermal injury patterns to perioral-related and dental structures is increasingly being recognized. This review delineates current burn-related dental health pathology and when available the underlying causation. These findings may help guide future research as well as therapeutic strategies to improve dental health and outcome for our patients.

Influence of Humeral Component Cement and Bone Grafting on Greater Tuberosity Healing and Functional Outcomes After Reverse Shoulder Arthroplasty for Proximal Humerus Fractures: A Systematic Review and Meta-Analysis

BACKGROUND

Reverse shoulder arthroplasty (RSA) is increasingly used in the treatment of displaced proximal humerus fractures (PHFs) with reliable clinical improvement. However, the preferred techniques for humeral stem fixation are varied and may be influenced by patient and injury characteristics, including bone quality and fracture pattern. This systematic review and meta-analysis sought to determine the effect of humeral component cementing and bone grafting on tuberosity healing rates and functional outcomes after RSA for PHFs.

METHODS

A systematic review was performed per Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. PubMed/MEDLINE, EMBASE, Web of Science, and Cochrane were queried for clinical studies on RSA performed for PHFs that reported on the use of cemented humeral stems and autograft bone. The primary outcome was the rate of greater tuberosity healing between the various techniques. Secondarily, the authors compared clinical outcomes including postoperative external rotation, forward elevation, abduction, Constant score, and the incidence of complications and revision surgery. Outcomes were compared based on the use of an uncemented press-fit stem, a fully cemented stem without bone graft, or a partially cemented stem with humeral head autograft (i.e., black and tan technique).

RESULTS

Forty-eight studies reporting on 1,797 RSAs were included (mean patient age, 75 years; follow-up, 34 months; 81% female). Tuberosity healing was highest in the uncemented cohort, then the black and tan cohort, and lowest in the cemented cohort (80% vs. 70% vs. 61%, p = 0.006). No significant differences in postoperative range of motion, Constant score, complication rates, or revision rates were found.

CONCLUSION

Uncemented fixation with a press-fit stem was associated with superior greater tuberosity healing rates; however, functional outcomes and complications did not differ among techniques.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Evaluation of Bone Density for Primary Implant Stability Using a Newly Designed Drill: An In Vitro Study on Polyurethane Bone Blocks

OBJECTIVES

Bone density is an important factor for long-term implant success. Peri-implant bone density evaluation before implant placement can be useful for treatment planning, such as the selection of proper implant size or drilling protocol in each case. In this study, we aimed to establish an objective intraoperative bone density evaluation method by measuring the drilling torque value using a newly designed density measurement drill.

MATERIALS AND METHODS

Drilling torque value measurement was performed intraoperatively using three types of drills; two previously reported drills and a newly designed drill as a density measurement drill. Polyurethane bone blocks of different densities (D1-D4) were used in this experiment. After the measurement, implants were inserted based on the scheduled plan, and insertion torque (IT) and implant stability quotient (ISQ) were measured to assess primary implant stability.

RESULTS

The drilling torque value increased with the bone blocks' density, and there were significant differences among different densities in all groups (p < 0.05). The drilling torque value showed a positive correlation with IT in all groups (p < 0.05). In addition, the drilling torque value increased with the increase in ISQ in all groups.

CONCLUSIONS

Within the limitations of this study, a newly designed density measurement drill was able to classify D1-D4 in polyurethane bone blocks despite its narrow diameter, and an objective intraoperative bone evaluation can be achieved. An intraoperative assessment of the drilling torque value can predict primary implant stability and provide valuable information for intraoperative treatment planning, such as undersized drilling protocol and implant size change.

Clinical Outcomes of Lunocapitate Arthrodesis: A Retrograde Single-Screw Approach

BACKGROUND

A single-site retrospective study was designed to evaluate the clinical outcomes of single-screw lunocapitate arthrodesis (LCA) using a retrograde approach for the treatment of scapholunate advanced collapse (SLAC) wrist.

METHODS

We retrospectively identified 31 patients (33 cases) between September 2010 and December 2019 with SLAC wrist changes who were treated with single-screw LCA. Objective outcomes included time to fusion, union rate, range of motion, and grip and pinch strength recovery. Subjective outcomes included Disabilities of the Arm, Shoulder, and Hand (DASH) scores.

RESULTS

We report on 33 cases (7 female), mean age 58.4 years (range: 41-85), with SLAC wrist who underwent LCA. Our cohort reported a 94% union rate and a 90-day mean time to fusion. Final active wrist range of motion was 38° dorsiflexion, 35° volarflexion, 17° radial deviation, 17° ulnar deviation, 82° pronation, and 83° supination (mean: 450.8 days). Final grip and pinch strengths recovered was 75% gross grip, 84% lateral pinch, and 75% precision pinch (mean: 379.0 days) compared with the contralateral side. The mean postoperative DASH score was 27 (mean: 1203.9 days). Two nonunions were observed. Two hardware complications occurred: one symptomatic screw and one screw fatigue fracture.

CONCLUSIONS

We found retrograde single-screw LCA to be an effective salvage procedure for SLAC wrist. LCA is a less-taxing procedure, requires shorter operating time, and produces range of motion and grip and pinch strength recovery comparable to those of 4-corner arthrodesis. Furthermore, the viability of single-screw fixation may reduce hardware-related operative costs without compromising union rates.

Photothermal Effect of 970 nm Diode Laser Irradiation on Enterococcus faecalis Biofilms in Single-Rooted Teeth Ex Vivo

Objective: The aim of this study was to evaluate the photothermal effect of a 970 nm diode laser on Enterococcus faecalis biofilms. Methods: 72 extracted human single-rooted teeth were prepared, sterilized, and inoculated with Enterococcus faecalis to establish a two-week-old biofilm. The specimens were divided into six groups (n = 12): Group 1 (G1)-negative control (PBS-no laser), Group 2 (G2)-positive control (1% NaOCl rinse-no laser), Group 3 (G3)-a 970 nm laser in 1.5 W pulse mode, Group 4 (G4)-a 970 nm laser in 2 W pulse mode, Group 5 (G5)-a 970 nm laser in 1.5 W continuous mode, Group 6 (G6)-a 970 nm laser in 2 W continuous mode. Bacterial viability was evaluated using the LIVE/DEAD BacLight kit and analyzed by flow cytometry (FCM). Temperature changes on the root surface during irradiation were analyzed using a K-type thermocouple. Data were statistically analyzed using one-way ANOVA and Tukey's multiple comparison test (α = 0.05). Results: Bacterial viability was significantly reduced after laser irradiation in continuous mode using 1.5 W (21% of live bacteria) and 2 W (14% of live bacteria). When the pulsed mode was applied, the reduction in bacterial viability was less, with a mean survival of 53% (1.5 PF, whereas 29% of bacteria survived after 2 W irradiation). Conclusions: The 970 nm diode laser at 2 W continuous mode effectively reduced the viability of E. faecalis biofilms in root canals without causing unacceptable temperature rises at the root surface.

Thermal Evaluation of Bone Drilling: Assessing Drill Bits and Sequential Drilling

Sequential drilling is a common practice in dental implant surgery aimed at minimizing thermal damage to bone. This study evaluates the thermal effects of sequential drilling and assesses modifications to drilling protocols to manage heat generation. We utilized a custom drill press and artificial bone models to test five drill bits under various protocols, including sequential drilling with different loads, spindle speeds, and peck drilling. Infrared thermography recorded temperature changes during the drilling process, with temperatures monitored at various depths around the osteotomy. The results reveal sequential drilling does not eliminate the thermal damage zone it creates (well over 70 °C). It creates harmful heat to surrounding bone that can spread up to 10 mm from the osteotomy. The first drill used in sequential drilling produces the highest temperatures (over 100 °C), and subsequent drill bits cannot remove the thermal trauma incurred; rather, they add to it. Modifying drill bit design and employing proper drilling techniques, such as reducing drilling RPM and load, can reduce thermal trauma by reducing friction. Inadequate management of heat can lead to prolonged recovery, increased patient discomfort, and potential long-term complications such as impaired bone-to-implant integration and chronic conditions like peri-implantitis. Ensuring healthy bone conditions is critical for successful implant outcomes.

Effect of Guided Implant Drilling on Bone Temperature Changes During Implant Osteotomy: A Comprehensive Systematic Review

The preparation of the implant site and the quality of the bone are crucial factors for preliminary healing following implant surgery. Therefore, any thermal or mechanical damage to the bone must be minimized during osteotomy preparation. The use of guided implant drilling is now widely employed for the precise placement of implants. Although guided implants are accurate, they are said to generate more heat compared to non-guided osteotomy. This systematic review was conducted to evaluate the heat generation that occurs during osteotomy with both guided and non-guided drilling. A comprehensive search of dental literature in PubMed, EBSCOhost, and Google Scholar was performed for articles published from 2010 to 2024. The search strategy incorporated MeSH terms and Boolean operators. The initial search across all three databases yielded a total of 548 articles. Of these, 477 were discarded after reviewing the titles and abstracts, 26 were removed as duplicates, 15 studies were excluded due to unavailable full texts, and 19 were excluded for not meeting the study design criteria set for the systematic review. Eleven articles were ultimately selected for review and data extraction. After analyzing and collating the results from all the studies, it can be concluded that using surgical guides does cause significant heat generation in the bone at the osteotomy site. However, this rise in temperature generally remains below the threshold that could cause bone necrosis. Additionally, other factors, such as irrigation temperature, drill length, drill diameter, and drilling speed, also influence heat generation during osteotomy in guided drilling.

Exploring morphometric transformations in temperature-sensitive NiTi instruments alongside real-time intracanal temperature dynamics

AIM

This study was twofold: (i) it aimed to investigate the morphometric changes of three temperature-sensitive nickel-titanium (NiTi) instruments at different temperatures, and (ii) to conduct an in vivo real-time analysis of intracanal temperature changes.

METHODS

Changes in the shape and length of XP-Endo Shaper, XP-Endo Finisher, and XP-Endo Finisher-R were evaluated in real time whilst heated in a temperature-controlled water bath from 22 to 45°C. Instruments were fixed to a laminated water-resistant 1 mm graph paper attached to a stone block. Instruments were imaged whilst subjected to increasing temperature using a digital camera attached to an operating microscope. From recorded videos, still frames were extracted at 10-s intervals and changes in the length and shape of each instrument were measured and changes were plotted against time. Moreover, the intracanal temperature of distal roots of lower molars was measured in vivo for patients attending the clinic for non-surgical root canal treatments. The temperature was measured using a K-type thermocouple probe inserted into the mid-root level after irrigating the canal with a solution set at room temperature (22°C) or heated to 45°C. The intraoral and intracanal temperatures were recorded using a video camera for 180 s at 5-s intervals to plot the change in the intraoral and intracanal temperature, after both irrigation solution temperatures, with time.

RESULTS

The shape transformation of XP-Endo Shaper began at 31.5 ± 2.0°C and reached its optimal transformation at 35.1 ± 1.0°C. For the Finisher and Finisher-R, shape transformations began at 29.2 ± 1.9 and 26.9 ± 2.2°C reaching the optimal transformation at 33.9 ± 1.4 and 32.7 ± 1.7°C, respectively. The average decreases in lengths of XP-Endo Shaper, Finisher, and Finisher-R after full transformation were 0.43 ± 0.23, 1.07 ± 0.22, and 1.15 ± 0.22 mm, respectively. The intracanal temperature reached 32.9 ± 0.8 and 33.2 ± 1.0°C after 3 min of application of irrigation solutions set at 22 or 45°C, respectively.

CONCLUSION

The tested instruments exhibited diverse changes in their shapes and lengths at varying temperatures. Despite the temperature of the irrigation solution, the intracanal temperature consistently remained lower than the intracanal temperature once equilibrium was reached. This highlights the importance of considering the temperature of irrigation solution during in vitro testing of endodontic instruments.

Slow drilling technique may enhance peri-operative patient-reported outcomes in dental implant surgery

STUDY DESIGN

A randomized, controlled, single-blind clinical trial.

OBJECTIVE

To assess and compare patient-reported outcome measures (PROMs) between low-speed drilling without irrigation and high-speed drilling with irrigation for implant site preparation.

PATIENTS AND METHODS

The study adhered to the Declaration of Helsinki principles, obtained approval from the local Ethics Committee, was registered on ClinicalTrials.gov, and was written in accordance with CONSORT guidelines. Included were adult patients with single posterior edentulism who exhibited good oral hygiene, sufficient bone dimensions for implant placement, adequate keratinized mucosa, stable occlusion, and a healthy periodontium. Patients were randomly assigned to either the test group (low-speed drilling (150 rpm) without irrigation) or the control group (high-speed drilling (800 rpm) with irrigation). A single dental implant was placed for each patient, with all surgeries conducted by the same experienced operator according to a standardized protocol. Patient satisfaction during surgery, including drilling-time perception, vibration, pressure, noise, comfort, and drowning sensation, as well as postoperative pain and inflammation, were assessed using a 100-mm visual analog scale. Quality of life (QOL) was evaluated using a 5-graded Likert scale for mouth opening, chewing, speaking, sleeping, daily routine, and job. Follow up extended on daily basis for 7 days. The PROMs were collected and analyzed in a blinded manner by independent researchers and a statistician to prevent bias.

RESULTS

The study included 66 patients (33 males and 33 females) with a mean age of 54.5 years. Patients in the test group reported a lower perception of drilling time, vibration, and noise but a higher perception of pressure compared to the control group; however, these differences were not statistically significant. Compared to the test group, patients in the control group experienced significantly greater drowning sensation and lesser comfort measures (p < 0.001). There was a moderate inverse correlation between drowning sensation and comfort (r = -0.57). The real drilling time was significantly longer in the test group compared to the control group (p < 0.001). The test group reported significantly lower pain levels during the first 12 h (p < 0.05), and significantly lower inflammation levels at the second day (p < 0.05) compared to the control group. No significant differences were observed between the groups at any time point for any of the QOL parameters (p > 0.05).

CONCLUSION

For a single implant site preparation, low-speed drilling without irrigation seems to offer greater patient comfort compared to high-speed drilling with irrigation, mainly due to reduced drowning sensation. Patients reported less postoperative pain and inflammation with the low-speed technique. Confirming these findings will require more research.

Design and performance analysis of low damage anti-skid crescent drills for bone drilling

BACKGROUND

With orthopedic surgery increasing year on year, the main challenges in bone drilling are thermal damage, mechanical damage, and drill skid. The need for new orthopedic drills that improve the quality of surgery is becoming more and more urgent.

METHODS

Here, we report the skidding mechanism of drills at a wide range of inclination angle and propose two crescent drills (CDTI and CDTII). The anti-skid performance and drilling damage of the crescent drills were analyzed for the first time. Inclined bone drilling experiments were carried out with crescent drills and twist drills and real-time drilling forces and temperatures were collected.

RESULTS

The crescent drills are significantly better than the twist drill in terms of anti-skid, reducing skidding forces, thrust forces and temperature. The highest temperature is generated close to the upper surface of the workpiece rather than at the hole exit. Finally, the longer crescent edge with a small and negative polar angle increases the rake angle of the cutting edge and reduces thrust forces but increases skidding force and temperature. This study can promote the development of high-quality orthopedic surgery and the development of new bone drilling tools.

CONCLUSION

The crescent drills did not skid and caused little drilling damage. In comparison, the CDTI performs better in reducing the skidding force, while the CDTII performs better in reducing the thrust force.

Primary stability evaluation of different morse cone implants in low-density artificial bone blocks: A comparison between high-and low-speed drilling

This study aimed to evaluate various biomechanical parameters associated with the primary stability of Maestro and Due Cone implants placed in low-density artificial bones, prepared using high-speed drilling with irrigation and low-speed drilling without irrigation. The insertion torque (IT), removal torque (RT), and implant stability quotient (ISQ) values were recorded for Maestro and Due Cone implants placed in low-density polyurethane blocks (10 and 20 pounds per cubic foot (PCF) with and without a cortical layer) prepared using high-speed and low-speed with or without irrigation using a saline solution, respectively. A three-way ANOVA model and Tukey's post-hoc test were conducted, presenting data as means and standard deviations. P-values equal to or less than 0.05 were considered statistically significant. No statistically significant differences in IT, RT, and ISQ between drilling speeds were observed. However, Maestro implants exhibited lower IT and RT values after high- and low-speed drilling across almost all polyurethane blocks, significantly evident in the 20 PCF density block for IT and in the 20 PCF density block with the cortical layer for the RT with low-speed drilling (IT: 47.33 ± 10.02 Ncm and 16.00 ± 12.49 Ncm for Due Cone and Maestro implants, respectively, with p < 0.01; RT: 44.67 ± 22.81 Ncm and 20.01 ± 4.36 Ncm for Due Cone and Maestro implants, respectively, with p < 0.05) and among the same implant types inserted in different bone densities. Additionally, the study found that for all bone densities and drilling speeds, both implants registered ISQ values exceeding 60, except for the lowest-density polyurethane block. Overall, it can be inferred that low-speed drilling without irrigation achieved biomechanical parameters similar to conventional drilling with both implant types, even with lower IT values in the case of Maestro implants. These findings suggest a promising potential use of low-speed drilling without irrigation in specific clinical scenarios, particularly when focusing on preparation depth or when ensuring proper irrigation is challenging.

Does increase in temperature of sodium hypochlorite have enhanced antimicrobial efficacy and tissue dissolution property? - A systematic review and meta-regression

Objectives

The objective of this study was to analyze the available evidence on the performance of increase in temperature of sodium hypochlorite on its antimicrobial efficacy and tissue dissolution property.

Materials and Methods

The study was conducted according to PRISMA guidelines, and a modified Joanna Briggs Institute (JBI) tool was used for quality assessment of the included studies. Two reviewers independently performed an electronic search in four databases along with the reference lists of the included articles.

Results

This systematic review included a total of 12 studies: antimicrobial efficacy (n = 6) and tissue dissolution property (n = 6). For the studies that were chosen, the overall risk of bias was moderate. Quantitative assessment through meta-regression was performed for tissue dissolution property. Low-concentration sodium hypochlorite irrigant (≤3%) shows a 0.13-unit times increase in tissue dissolution ability with a degree rise in temperature although not statistically significant.

Conclusion

Due to inconsistency in the study parameters, results pertaining to the exclusive effect of increase in the temperature of sodium hypochlorite remain inconclusive.

Excessive Heat Generation by Power-Driven Craniotomy Tools: A Possible Cause of Autologous Bone Flap Resorption Observed in an Ex Vivo Simulation

BACKGROUND

Bone flap resorption is an issue after autologous cranioplasty. Critical temperatures above 50°C generated by power-driven craniotomy tools may lead to thermal osteonecrosis, a possible factor in resorption. This ex vivo study examined whether the tools produced excessive heat resulting in bone flap resorption.

METHODS

Using swine scapulae maintained at body temperature, burr holes, straight and curved cuts, and wire-pass holes were made with power-driven craniotomy tools. Drilling was at the conventional feed rate (FR) plus irrigation (FR-I+), at a high FR plus irrigation (hFR-I+), and at high FR without irrigation (hFR-I-). The temperature in each trial was recorded by an infrared thermographic camera.

RESULTS

With FR-I+, the maximum temperature at the burr holes, the cuts, and the wire-pass holes was 69.0°C, 56.7°C, and 46.2°C, respectively. With hFR-I+, these temperatures were 53.1°C, 52.1°C, and 46.0°C, with hFR-I- they were 56.0°C, 66.5°C, and 50.0°C; hFR-I- burr hole- and cutting procedures resulted in the highest incidence of bone temperatures above 50°C followed by FR-I+, and hFR-I+. At the site of wire-pass holes, only hFR-I- drilling produced this temperature.

CONCLUSIONS

Except during prolonged procedures in thick bones, most drilling with irrigation did not reach the critical temperature. Drilling without irrigation risked generating the critical temperature. Knowing those characteristics may be a help to perform craniotomy with less thermal bone damage.

Standardized Testing for Thermal Evaluation of Bone Drilling: Towards Predictive Assessment of Thermal Trauma

To ensure the prevention of thermal trauma and tissue necrosis during bone drilling in surgical procedures, it is crucial to maintain temperatures below the time- and temperature-dependent threshold of 50 °C for 30 s. However, the absence of a current standard for assessing temperatures attained during bone drilling poses a challenge when comparing findings across different studies. This article aims to address this issue by introducing a standardized testing method for acquiring thermal data during experimental bone drilling. The method requires the use of three controlled variables: infrared thermography, standard bone blocks, and a regulated drilling procedure involving a drill press with irrigation that simulates a surgeon. By utilizing this setup, we can obtain temperature data that can be effectively applied in the evaluation of other variables, such as surgical techniques or drill bit design, and translate the data into bone damage/clinical outcomes. Two surgical drill bits (2.0 mm-diameter twist drill bit and 3.3 mm-diameter multi-step drill bit) are compared using this experimental protocol. The results show the 2.0 mm bit reached significantly higher temperatures compared to the 3.3 mm bit when preparing an osteotomy (p < 0.05). The 2.0 mm drill bit reached temperatures over 100 °C while the 3.3 mm drill bit did not exceed 50 °C.

Temperature variations during bone removal procedures similar to third molar extraction using different instruments

Bone removal is commonly used in the extraction of third molars and the heat generated during the process can interfere with the repair of bone. The aim of this study was to evaluate the temperature variation presented in bone removal performed with a high-speed turbine (400000 rpm), implant motor with straight piece (100000 rpm), low-speed micromotor (20000 rpm) and piezoelectric saw (30 kHz) in pig mandibles. For this, bone removal was carried out around 20 posterior teeth, under constant saline solution irrigation with a syringe and needle. In addition, the time required to perform bone removal was recorded. The results indicated a mean (SD) temperature variation of 0.96 °C (0.6 °C) for the high-speed turbine, 1.38 °C (0.5 °C) with the implant motor, 2.22 °C (0.7 °C) for the low-speed micromotor and 2.90 °C (1.3 °C) for the piezoelectric saw. The conventional variance was calculated discounting the variation of time used for bone removal around the teeth. There was a statistically significant difference in temperature variation between the high-speed turbine vs the micromotor (p = 0.009) and the high speed micromotor vs the piezoelectric saw (p = 0.04). We conclude that there is a statistically significant difference in temperature variation between the instruments used in oral and maxillofacial surgery, with higher rotation speeds resulting in the lowest temperature variations and a reduced surgical time.

Digital workflow for creating a coolant channel for direct irrigation through an implant surgical guide

Heat elicited during the osteotomy for implant placement may have a significant impact on the vitality of surrounding bone and on the healing capacity for osseointegration. This article describes a digital workflow for creating a coolant channel for the direct irrigation of the osteotomy site through an implant surgical guide. This technique can be particularly advantageous when the surgical guide restricts access for direct irrigation of the osteotomy site.

The Safety of Removing Fractured Nickel-Titanium Files in Root Canals Using a Nd: YAP Laser

The fracture of nickel-titanium (Ni-Ti) instruments during root canal instrumentation leads to compromised outcomes in endodontic treatments. Despite the significant impact of instrument facture during a root canal treatment, there is still no universally accepted method to address this complication. Several previous studies have shown the ability of a Neodymium: Yttrium-Aluminum-Perovskite (Nd: YAP) laser to cut endodontic files. This study aims to determine safe irradiation conditions for a clinical procedure involving the use of a Neodymium: Yttrium-Aluminum-Perovskite (Nd: YAP) laser for removing fractured nickel-titanium files in root canals. A total of 54 extracted permanent human teeth (n = 54) were used. This study involved nine distinct groups, each employing different irradiation conditions. Groups 1 s, 3 s, 5 s, 10 s, and 15 s simply consist of irradiation for 1, 3, 5, 10, and 15 s, respectively. After identifying the longest and safest duration time, four additional groups were proposed (labeled A, B, C, and D). Group A was composed of three series of irradiations of 5 s each separated by a rest time of 30 s (L5s + 30 s RT). Group B consisted of three series of irradiations of 5 s each separated by a rest time of 60 s (L5s + 60 s RT). Group C consisted of two series of irradiations of 5 s each separated by a rest time of 30 s (L5s + 30 s RT), and group D consisted of two series of irradiations of 5 s each separated by a rest time of 5 s (L5s + 5 s RT). In all groups, during the rest time, continuous irrigation with 2.5 mL of sodium hypochlorite (3% NaOCl) was carried out. The variation in temperature during irradiation was registered with a thermocouple during irradiation with different protocols. The mean and standard deviation of the temperature increase was noted. The calculation of the temperature was made as the Δ of the highest recorded temperature at the root surface minus (-) that recorded at baseline (37°). Additionally, scanning electron microscopy (SEM) was used after irradiation in all groups in order to assess the morphological changes in the root dentinal walls. The Nd: YAP laser irradiation parameters were a power of 3W, an energy of 300 mJ per pulse, a fiber diameter of 200 µm, a pulsed mode of irradiation with a frequency of 10 Hz, a pulse duration of 150 µs, and an energy density of 955.41 J/cm2. Our results show that the safest protocol for bypassing and/or removing broken instruments involves three series of irradiation of 5 s each with a rest time of 30 s between each series. Furthermore, our results suggest that continuous irradiation for 10 s or more may be harmful for periodontal tissue.

Thermal Damage in Orthopaedics

There are numerous potential sources of thermal damage encountered in orthopaedic surgery. An understanding of the preclinical mechanisms of thermal damage in tissues is necessary to minimize iatrogenic injuries and use these mechanisms therapeutically. Heat generation is a phenomenon that can be used to a surgeon's benefit, most commonly for hemostasis and local control of tumors. It is simultaneously one of the most dangerous by-products of orthopaedic techniques as a result of burring, drilling, cementation, and electrocautery and can severely damage tissues if used improperly. Similarly, cooling can be used to a surgeon's advantage in some orthopaedic subspecialties, but the potential for harm to tissues is also great. Understanding the potential of a given technique to rapidly alter local temperature-and the range of temperatures tolerated by a given tissue-is imperative to harness the power of heat and cold. In all subspecialties of orthopaedic surgery, thermal damage is a relevant topic that represents a direct connection between preclinical and clinical practice.

Using Computed Tomography-Based Three-dimensional Modeling and Computer Navigation for Minimally Invasive Core Decompression and Adjuvant Orthobiologic Therapy of Femoral Head Avascular Necrosis

Avascular necrosis of the femoral head is a debilitating condition that can lead to femoral head collapse. Core decompression with adjuvant cellular therapies, such as bone marrow aspirate concentrate, delays disease progression and improves outcomes. However, inconsistent results in the literature may be due to limitations in surgical technique and difficulty in targeting the necrotic lesions. Here, we present a surgical technique utilizing computed tomography-based three-dimensional modeling and instrument tracking to guide the therapy to the center of the lesion. This method minimizes the number of attempts to reach the lesion and confirms the three-dimensional positioning of the instrumentation within the lesion. Our technique may improve the outcomes of core decompression and adjuvant therapy and prevent or delay hip collapse in patients with femoral head avascular necrosis.

The efficacy of 2780 nm Er,Cr;YSGG and 940 nm Diode Laser in root canal disinfection: A randomized clinical trial

OBJECTIVES

Effective disinfection of the root canals is the cornerstone of successful endodontic treatment. Diminishing the microbial load within the root canal system is crucial for healing in endodontically treated teeth. The aim of this study was to evaluate the effect of 2780 nm Er,Cr:YSGG and 940 nm diode lasers on the eradication of microorganisms from single-rooted teeth with asymptomatic apical periodontitis.

MATERIALS AND METHODS

Thirty participants conforming to the inclusion criteria were randomly divided into 3 groups according to the disinfection protocol used; Conventional group: 2.5% Sodium Hypochlorite (NaOCl) and 17% EDTA solution NaOCl/EDTA, Dual laser group: 2780 nm Erbium, chromium: yttrium scandium-gallium-garnet (Er,Cr:YSGG) laser and 940 nm diode laser Er,CrYSGG/Diode, and Combined group: 17% EDTA and 940 nm diode laser EDTA/Diode. Bacterial samples were collected before and after intervention. The collected data were statistically analyzed using Friedman's test and Kruskal-Wallis test (P ≤ 0.05).

RESULTS

The results of the study showed that both dual laser Er,CrYSGG/Diode and combined laser EDTA/Diode groups showed significantly less mean Log10 CFU/ml of aerobic and anaerobic bacterial counts than the conventional NaOCl/EDTA group.

CONCLUSIONS

In this study we evaluated in vivo the bactericidal efficacy of three disinfection protocols for endodontic treatment of single-rooted teeth with apical periodontitis. The results indicated that both dual laser Er,CrYSGG/Diode and combined laser EDTA/Diode groups provide superior bactericidal effect compared to the conventional NaOCl/EDTA group.

CLINICAL RELEVANCE

The integration of lasers into root canal disinfection protocols has demonstrated significant bacterial reduction which might promote healing and long-term success.

Influence of various pilot hole profiles on pedicle screw fixation strength in minimally invasive and traditional spinal surgery: a comparative biomechanical study

Despite advancements in pedicle screw design and surgical techniques, the standard steps for inserting pedicle screws still need to follow a set of fixed procedures. The first step, known as establishing a pilot hole, also referred to as a pre-drilled hole, is crucial for ensuring screw insertion accuracy. In different surgical approaches, such as minimally invasive or traditional surgery, the method of creating pilot holes varies, resulting in different pilot hole profiles, including variations in size and shape. The aim of this study is to evaluate the biomechanical properties of different pilot hole profiles corresponding to various surgical approaches. Commercially available synthetic L4 vertebrae with a density of 0.16 g/cc were utilized as substitutes for human bone. Four different pilot hole profiles were created using a 3.0 mm cylindrical bone biopsy needle, 3.6 mm cylindrical drill, 3.2-5.0 mm conical drill, and 3.2-5.0 mm conical curette for simulating various minimally invasive and traditional spinal surgeries. Two frequently employed screw shapes, namely, cylindrical and conical, were selected. Following specimen preparation, screw pullout tests were performed using a material test machine, and statistical analysis was applied to compare the mean maximal pullout strength of each configuration. Conical and cylindrical screws in these four pilot hole configurations showed similar trends, with the mean maximal pullout strength ranking from high to low as follows: 3.0 mm cylindrical biopsy needle, 3.6 mm cylindrical drill bit, 3.2-5.0 mm conical curette, and 3.2-5.0 mm conical drill bit. Conical screws generally exhibited a greater mean maximal pullout strength than cylindrical screws in three of the four different pilot hole configurations. In the groups with conical pilot holes, created with a 3.2-5.0 mm drill bit and 3.2-5.0 mm curette, both conical screws exhibited a greater mean maximal pullout strength than did cylindrical screws. The strength of this study lies in its comprehensive comparison of the impact of various pilot hole profiles commonly used in clinical procedures on screw fixation stability, a topic rarely reported in the literature. Our results demonstrated that pilot holes created for minimally invasive surgery using image-guided techniques exhibit superior pullout strength compared to those utilized in traditional surgery. Therefore, we recommend prioritizing minimally invasive surgery when screw implantation is anticipated to be difficult or there is a specific need for stronger screw fixation. When opting for traditional surgery, image-guided methods may help establish smaller pilot holes and increase screw fixation strength.

Effectiveness of mechanical and chemical decontamination methods for the treatment of dental implant surfaces affected by peri-implantitis: A systematic review and meta-analysis

OBJECTIVE

To assess which decontamination method(s) used for the debridement of titanium surfaces (disks and dental implants) contaminated with bacterial, most efficiently eliminate bacterial biofilms.

MATERIAL AND METHODS

A systematic search was conducted in four electronic databases between January 1, 2010 and October 31, 2022. The search strategy followed the PICOS format and included only in vitro studies completed on either dental implant or titanium disk samples. The assessed outcome variable consisted of the most effective method(s)-chemical or mechanical- removing bacterial biofilm from titanium surfaces. A meta-analysis was conducted, and data was summarized through single- and multi-level random effects model (p < .05).

RESULTS

The initial search resulted in 5260 articles after the removal of duplicates. After assessment by title, abstract, and full-text review, a total of 13 articles met the inclusion criteria for this review. Different decontamination methods were assessed, including both mechanical and chemical, with the most common method across studies being chlorhexidine (CHX). Significant heterogeneity was noted across the included studies. The meta-analyses only identified a significant difference in biofilm reduction when CHX treatment was compared against PBS. The remaining comparisons did not identify significant differences between the various decontamination methods.

CONCLUSIONS

The present results do not demonstrate that one method of decontamination is superior in eliminating bacterial biofilm from titanium disk and implant surfaces.

Cooling Efficiency of Sleeveless 3D-Printed Surgical Guides with Different Cylinder Designs

Background and Objectives: Surgical guides might impede the flow of coolant to the implant drills during the preparation of the implant bed, potentially contributing to increased temperatures during bone drilling. The objective of this experimental study was to assess the cooling efficiency of various guiding cylinder designs for sleeveless surgical guides used in guided surgery. Materials and Methods: In this experimental study, surgical guides with three different guiding cylinder designs were printed. One group had solid cylinders (control) and two test groups (cylinders with pores and cylinders with windows). Forty customized polyurethane blocks with type III bone characteristics were fitted into the guide and fixed in a vise, and implant bed preparations were completed using a simplified drilling protocol with and without irrigation. An infrared thermographic camera was used to record the temperature changes during drilling at the coronal, middle, and apical areas. ANOVA test and Games-Howell post hoc test were used to determine significant thermal differences among groups. Results: A significant thermal increase was observed at the coronal area in the group without irrigation (39.69 ± 8.82) (p < 0.05). The lowest thermal increase was recorded at the surgical guides with windows (21.451 ± 0.703 °C) compared to solid (25.005 ± 0.586 °C) and porous surgical guides (25.630 ± 1.004) (p < 0.05). In the middle and apical areas, there were no differences between solid and porous cylinders (p > 0.05). Conclusions: 3D-printed sleeveless surgical guides with window openings at the guiding cylinders reduce the temperature elevation at the cortical bone in guided implant surgery.

Effect of different parameters utilized for image guided endodontic root canal preparation on temperature changes: an in vitro study

BACKGROUND

Navigated endodontics is a cutting-edge technology becoming increasingly more accessible for dental practitioners. Therefore, it is necessary to clarify the ideal technical parameters of this procedure to prevent collateral damage of the surrounding tissues. There is a limited number of studies available in published scientific literature referencing the possible collateral thermal damage due to high-speed rotary instruments used in guided endodontic drilling. The aim of our study was to investigate the different drilling parameters and their effect upon the temperature elevations measured on the outer surface of teeth during guided endodontic drilling.

METHODS

In our in vitro study, 72 teeth with presumably narrow root canals were prepared using a guided endodontic approach through a 3D-printed guide. Teeth were randomly allocated into six different test groups consisting of 12 teeth each, of which, four parameters affecting temperature change were investigated: (a) access cavity preparation prior to endodontic drilling, (b) drill speed, (c) cooling, and (d) cooling fluid temperature. Temperature changes were recorded using a contact thermocouple electrode connected to a digital thermometer.

RESULTS

The highest temperature elevations (14.62 °C ± 0.60 at 800 rpm and 13.76 °C ± 1.24 at 1000 rpm) were recorded in the groups in which drilling was performed without prior access cavity preparation nor without a significant difference between the different drill speeds (p = 0.243). Access cavity preparation significantly decreased temperature elevations (p < 0.01) while drilling at 800 rpm (8.90 °C ± 0.50) produced significantly less heating of the root surface (p < 0.05) than drilling at 1000 rpm (10.09 °C ± 1.32). Cooling significantly decreased (p < 0.01) temperature elevations at a drill speed of 1000 rpm, and cooling liquid temperatures of 4-6 °C proved significantly (p < 0.01) more beneficial in decreasing temperature elevations (1.60 °C ± 1.17) than when compared with room temperature (21 °C) liquids (4.01 °C ± 0.22).

CONCLUSIONS

Based on the results of our study, guided endodontic drilling at drill speeds not exceeding 1000 rpm following access cavity preparation, with constant cooling using a fluid cooler than room temperature, provides the best results in avoiding collateral thermal damage during navigated endodontic drilling of root canals.

Steel drills versus zirconia drills on heat generation at the surgical site of dental implants: A systematic review and meta-analysis

Objective

The aim was to evaluate the difference in the heat generated between zirconia (Zr) and steel (SS) drills, during implant site preparation.

Material and methods

This systematic review followed the PRISMA methodology criteria and used the JBI Critical Assessment Guidelines for Quasi-Experimental Studies for quality assessment. The electronic search was conducted by using the PubMed/MEDLINE, Embase, and Cochrane Library databases to January 2023. The formulated population, intervention, comparison, outcome (PICO) question was "Do zirconia drills generate less heat than steel drills during implant site preparation?". The meta-analysis was based on an inverse variance (IV) method.

Results

This review included 10 studies in vitro that used zirconia drills compared to steel drills with or without coatings. The meta-analysis indicated a significant difference between Zr drills and SS drills, with a lower bone temperature variation with Zr drills.

Conclusions

Despite the limitations of this review, it was concluded that Zr drills had significantly less temperature variation than SS drills.

Comparison of the Efficacy and Safety of Pulp Sensitivity Testing Results Using a New Pulp Testing Device versus Some Commonly Used Methods: A Crossover Study

INTRODUCTION

The efficacy and safety of a single novel electronic pulp sensitivity tester with a transilluminator (PSTT) capable of providing 4 different tests was compared with gold standard (GS) pulp testing methods.

METHODS

Four hundred eighty teeth, including 3 from each quadrant and their contralateral and opposing teeth, were randomly assessed using the PSTT or GS methods. Seven days later, the same teeth were assessed using the method not used earlier so that all teeth were evaluated using both methods. Sixty previously root canal-treated teeth, serving as negative controls, were assessed identically to the experimental groups. Results were analyzed using IBM SPSS software (IBM Corp, Armonk, NY) (P < .05).

RESULTS

A higher percentage of teeth responded to cold and electricity using GS methods compared with the PSTT (99.4 vs 93.1 and 99.6 vs 97.3, respectively). A lower percentage of teeth responded to heat using the GS method compared with the PSTT (50.0 vs 68.1). Chi-square tests determined differences in the proportion of sensitivity to temperature, and electric testing methods were statistically significant (P < .001 and P = .004, respectively). No difference in the proportion of sensitivity was observed for transillumination. The Wilcoxon signed rank test determined significantly shorter cold testing times using the GS method (P = .024). Shorter testing times were observed using the PSTT for heat (P < .001), electric pulp testing (P = .048), and transillumination (P = .001). The overall PSTT testing time was significantly shorter than the GS testing time (P = .03). Tissue injury was not observed.

CONCLUSIONS

The PSTT efficiently and safely provided heat and transillumination for pulpal diagnosis. Improvements are needed to enhance the cold and electric stimulus efficacy.

Optimizing milling parameters based on full factorial experiment and backpropagation artificial neural network of lamina milling temperature prediction model

BACKGROUND

Milling operations of laminae in spinal surgery generate high temperatures, which can lead to thermal injury and osteonecrosis and affect the biomechanical effects of implants, ultimately leading to surgical failure.

OBJECTIVE

In this paper, a backpropagation artificial neural network (Bp-ANN) temperature prediction model was developed based on full factorial experimental data of laminae milling to optimize the milling motion parameters and to improve the safety of robot-assisted spine surgery.

METHODS

A full factorial experiment design were used to analyze the parameters affecting the milling temperature of laminae. The experimental matrixes were established by collecting the corresponding cutter temperature Tc and bone surface temperature Tb for the milling depth, feed speed and different bone densities. The Bp-ANN lamina milling temperature prediction model was constructed from experiment data.

RESULTS

Increasing milling depth increases bone surface and cutter temperature. Increasing feed speed had little effect on cutter temperature, but decreased bone surface temperature. Increasing bone density of laminae increased cutter temperature. The Bp-ANN temperature prediction model had best training results in the 10th epoch, and there is no overfitting (training set R= 0.99661, validation set R= 0.85003, testing set R= 0.90421, all temperature data set R= 0.93807). The goodness of fit R of Bp-ANN was close to 1, indicating that the predicted temperature was in good agreement with the experiment measurements.

CONCLUSION

This study can help spinal surgery-assisted robot to select appropriate motion parameters at different density bones to improve lamina milling safety.

Evaluation of the effectiveness and practicality of erbium lasers for ceramic restoration removal: A retrospective clinical analysis

BACKGROUND

The purpose of this study was to assess the effectiveness and practicality of erbium lasers in the removal of ceramic restorations and appliances from natural teeth and dental implant abutments in clinical practice.

METHODS

A retrospective analysis was conducted, involving 29 clinical cases with a total of 52 abutments requiring the removal of various ceramic restorations. The analysis evaluated the clinical procedures performed, including the type and material of the prosthetic, the type of cement used, laser setting parameters, retrieval time, and retrieval success.

RESULTS

Out of the 52 abutments, 50 were successfully retrieved without causing any damage (>95%) using either an Er,Cr:YSGG laser (N = 6) or an Er:YAG laser (N = 46). In one case, a crown was partially sectioned to prevent any negative impact of laser irradiation on the adhesive strength between the post and tooth, and in another case, a fracture occurred during debonding. The restorations consisted of 13 lithium disilicate and 39 zirconia units, including six veneers, 38 single crowns, and three fixed partial dentures (FPDs). The retrieval time varied depending on the restoration type, material thickness, cement type, retention form/fitting of the abutment and restoration, ranging from 2.25 ±0.61 minutes for veneers, 6.89 ±8.07 minutes for crowns, to 25 ±10 minutes per abutment for FPDs. Removal of a zirconia crown required more time, 7.12±8.91 minutes, compared to a lithium disilicate crown, 5.86 ±2.41 minutes. The debonding time was influenced by the laser settings as well as materials and types of prosthesis.

CONCLUSIONS

Erbium lasers present a safe and effective alternative to invasive methods for removing ceramic restorations, without causing harm to the abutment or prosthesis. Laser-assisted debonding allows for recementation of the restorations during the same appointment, making it a conservative and viable option for ceramic crown retrieval in clinical settings.

Implications of ageing effects on thermal and mechanical properties of PMMA-based bone cement for THA revision surgery

Loosening and infection are the main reasons for revision surgery in total hip arthroplasty (THA). Removing partially detached cemented implant components during revision surgery remains challenging and poses the risk of periprosthetic bone damage. A promising approach for a gentler removal of partially detached prostheses involves softening the PMMA-based bone cement by heating it above its glass transition temperature (TG), thus loosening the implant-cement bond. It is assumed that the TG of PMMA-based bone cement decreases in-vivo due to the gradual absorption of body fluid. Reliable data on TG are essential to develop a heat-based method for removing cemented implant components during revision surgery. The effect of water absorption was investigated in-vitro by ageing PMMA-based bone cement samples for different periods up to 56 days in both Ringer's solution (37 °C) and air (37 °C and 30% humidity). Subsequently, the TG and Vicat softening temperatures of the samples were determined by differential scanning calorimetry and Vicat tests, respectively, according to prescribed methods. Over the entire ageing period, i.e. comparing one day of ageing in air and 56 days in Ringer's solution, the Vicat softening temperature dropped by 16 °C, while the TG dropped by 10 °C for Palacos® R PMMA-based bone cement. Water absorption over time correlated significantly with the Vicat softening temperature until saturation of the PMMA-based bone cement was reached. Based on the TG and Vicat softening temperature measurements, it can be assumed that in body-aged bone cement, an optimal softening can be achieved within a temperature range of 85 °C-93 °C to loosen the bond between the PMMA-based bone cement mantle and the prosthesis stem. These findings may pave the way for a gentler removal of the implant in revision THA.

An Evaluation of the Effect of Using Irrigations at Different Temperatures on Pain, Edema, and Trismus during the Extraction of Bilateral Impacted Mandibular Third Molars: A Randomized Split-Mouth Clinical Trial

BACKGROUND AND AIM

The surgical extraction of impacted wisdom teeth is a standard practice in dentistry. Unfortunately, inflammatory reactions such as discomfort, edema, and trismus frequently jeopardize patients' well-being after the extraction of third molars. Saline solutions at room temperature (25°C) are routinely used in impacted tooth extraction. Refrigerated saline solutions were used to work with cold solutions, and as the refrigerator temperature was 4°C, this study was designed to have a cold solution temperature of 4°C. This study aimed to assess the influence of saline irrigation at various temperatures (4°C, 25°C) on postoperative edema, pain, and trismus after the extraction of impacted third molars.

MATERIALS AND METHODS

Eighteen patients with bilateral symmetrical mandibular impacted third molars were enrolled in this split-mouth, randomized, prospective, double-blind clinical trial. For each patient, one side was irrigated with a saline solution (% 0.9 isotonic sodium chloride) at 4°C (test), and the other side was irrigated with a saline solution at room temperature (25°C) (control). Pain, trismus, and facial edema were noted on the 2nd, 4th, and 7th days. A Mann-Whitney U-test was used to compare pairs, and a Wilcoxon signed-rank test was used to compare groups.

RESULTS

The two groups had no considerable differences in terms of pain levels and facial edema (P > 0.05). Regarding trismus, the maximum mouth opening for cold irrigation (4°C) was significantly higher than for room temperature irrigation (25°C) across all postoperative periods (P < 0.05).

CONCLUSION

Cold irrigation therapy (4°C) exerts beneficial effects more than room temperature (25°C) irrigation on the trismus after impacted mandibular third molar surgery.