Effect of the Combination of Low-Speed Drilling and Cooled Irrigation Fluid on Intraosseous Heat Generation During Guided Surgical Implant Site Preparation: An In Vitro Study

Comparative Analysis of the Histological Characteristics of Bone Tissue Following Implant Drill Preparation Under Various Parameters: An In Vitro Study

Purpose: This study aimed to compare the histological characteristics of bone tissue following drilling with three implant systems under different rotational speeds and cooling conditions. Methods: A total of 54 implant bed preparations were performed in four swine ribs using three implant systems: Hiossen ET (Hiossen, Fairfield, NJ, USA), Paltop (Burlington, MA, USA), and Anyridge (Megagen, Daegu, Republic of Korea). Drilling was performed at three speeds (800, 1200, and 1500 rpm) under three cooling conditions: saline at room temperature, saline cooled to 4 °C, and no cooling. Histological evaluation was conducted using a Nikon Eclipse 80i fluorescence microscope (Nikon, Tokyo, Japan) with DAPI and rhodamine staining. Observations were performed at 40× magnification, focusing on the osteotomy wall and surrounding tissue. The samples were assessed based on surface smoothness, compressed tissue presence, carbonization, and adjacent tissue damage. Statistical analysis was performed using the Kruskal-Wallis test with Dunn's post hoc comparisons to evaluate differences among experimental conditions. Results: The results demonstrated that the Hiossen ET system achieved optimal bone bed quality at 1200 rpm with saline cooling at 4 °C, producing the smoothest osteotomy walls and minimal thermal damage (p = 0.003). The Paltop system performed best at 800 rpm with 4 °C cooling, showing reduced tissue compression and fewer microcracks (p = 0.012). The Anyridge system exhibited the most favorable outcomes at 1200 rpm with saline cooling at room temperature, minimizing soft tissue remnants and preserving bone integrity (p = 0.021). Across all systems, the absence of cooling significantly increased thermal damage, carbonization, and tissue fragmentation, particularly at 1500 rpm (p < 0.001). Conclusions: The use of lower rotational speeds with effective cooling minimized tissue trauma and improved bone bed integrity. Further clinical validation is necessary to confirm the applicability of these results in human bone.

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.

Accuracy of a custom two-piece surgical guide for all-on-four dental implant placement: An in vitro study

STATEMENT OF PROBLEM

Although fully guided dental implant surgery has been reported to provide a high degree of accuracy, it has disadvantages including the lack of external irrigation during osteotomy formation and the need for special drills and equipment. Whether a custom 2-piece surgical guide has sufficient accuracy is unclear.

PURPOSE

The purpose of this in vitro study was to design and fabricate a new surgical guide concept that fully guides the placement of implants to the desired position and angulation without affecting the external irrigation during osteotomy preparation, to eliminate the need for a special armamentarium, and to determine the accuracy of the guide.

MATERIAL AND METHODS

A 2-piece surgical guide was 3-dimensionally designed and fabricated. Implants were placed according to the all-on-4 concepts in laboratory casts using the newly fabricated surgical guide. Placement accuracy was determined from a postoperative cone beam computed tomography scan that was superimposed over the preplanned implant positions to calculate the degree of angular deviation and position of placement. Adopting 5% alpha error and 80% study power in estimating sample size, a total of 88 implants were placed according to the all-on-4 concept in 22 mandibular laboratory casts. These were divided into 2 groups: with the newly fabricated surgical guide and with a traditional fully guided protocol. Deviations at the point of entry, at the apex horizontally, the vertical apical depth, and angular deviations from the proposed plan were measured from the superimposed scans. Differences in apical depth, horizontal deviation at the apex, and horizontal deviation in the hexagon measurements were compared with the independent t test, while differences in angular deviation were assessed with the Mann-Whitney U test (α=.05).

RESULTS

No statistically significant difference was found in the apical depth deviation (P>.05), but significant differences were found in the apex (P=.002), hexagon (P<.001), and angular deviation (P<.001) between the new guide and the traditional guide.

CONCLUSIONS

The new surgical guide showed potential for higher accuracy in implant placement when compared with the fully guided sleeveless surgical guide. In addition, it provided an undisturbed flow of irrigation around the drill throughout the drilling procedure, with the advantage of eliminating the special armamentarium usually required.

The impact of surgical guide design and bone quality on heat generation during pilot implant site preparation: an in vitro study

BACKGROUND

Surgical guides restrict the flow of cooling agent to osteotomy site, which will lead to a temperature rise that provokes tissue injury. Few studies compared differences in the temperature changes between non-limiting 'conventional' and limiting 'guided' surgical guides during implant site preparation. The objective of this study was to investigate the difference in temperature changes during bone drilling for implant placement using non-limiting and limiting surgical guides at cortical and cancellous bone levels.

METHODS

Forty-four bovine rib samples were used for implant bed preparation in this study with a minimum thickness of 11 mm was chosen for the ribs. The bone was stored in a freezer at 10 °C until it was used. On the day of the study, the bone was defrosted and soaked in water at 21 °C for three hours before embarking on drilling to make sure each sample was at the same temperature when tested. Forty-four bone specimens were prepared and randomly allocated to receive either a limiting or a non-limiting surgical guides (22 for each group). The osteotomy site was prepared by one operator following the manufacturer's instructions, using limiting and non-limiting surgical guides. Temperature changes were recorded during implant bed preparation using thermocouples that fit into 7 mm-horizontal channels at two different depths (Coronally) and (Apically) at 1 mm distance from the osteotomy site. The data were tested for homogeneity of variances using Levene's test, then data were analyzed using an Independent sample t-test and the significance level was set at P ≤ 0.05.

RESULTS

The mean temperature rise for all samples was 0.55 °C. The mean temperature rises for the limiting and non-limiting surgical guides were 0.80 °C and 0.33 °C respectively. There was a statistically significant difference in temperature rise between the limiting and non-limiting surgical guides (P = 0.008). In relation to position of temperature recording (coronal vs. apical), there was no significant difference (P > 0.05). No significant difference was noted between the two groups at cancellous bone level (P = 0.68), but the difference was significant at cortical bone level (P = 0.036).

CONCLUSION

Limiting surgical guides showed higher readings than non-limiting. However, for both techniques, temperature rise was not significant clinically and within a safe range.

Does Saline Irrigation at Different Temperatures Affect Pain, Edema, and Trismus After Impacted Third Molar Surgery: A Clinical Trial

PURPOSE

Lower impacted third molar surgery is a very common oral-maxillofacial surgical procedure, which has complications such as facial swelling, pain, and trismus. This clinical trial aimed to compare the intensity of postoperative morbidity (pain, facial swelling, and trismus) following the third molar surgery performed using saline irrigation at different temperatures (4 °C, 10 °C, or 25 °C).

MATERIALS AND METHODS

This double-blind, single-center, split-mouth, randomized prospective clinical trial was conducted among 48 systemically and periodontally healthy patients who had bilaterally asymptomatic mandibular third molars. Patients were randomly allocated into 2 groups (n = 24) according to the temperature of the saline used. In each patient, one impacted third molar was determined as the test group (4 °C or 10 °C saline irrigation) and the other impacted third molar as the control group (25 °C saline irrigation). Trismus and swelling were evaluated on the 1^st, 3^rd, and 7^th days postoperatively. Pain perception by visual analog scale (VAS) and the total number of analgesics taken during the 7 postoperative days were recorded. Data were analyzed using the Shapiro-Wilk test, the chi-square test, one-way analysis of variance, Duncan test, the Kruskal-Wallis test, the Dunn test, and the Friedman test (P < .05).

RESULTS

Forty-eight patients (28 females, 20 males) with a mean age of 24.6 ± 3.8 years were included in the study. The duration of operations was similar. VAS values of test groups [test group 1 (4 °C): 4.0, test group 1 (10 °C): 8.0] and the number of analgesics taken [test group 1 (4 °C): 0, test group 1 (10°) C): 3] were significantly lower (P < .001) than control groups (VAS, control group 1: 13.0, control group 2: 15.5, number of analgesic taken, control group 1: 5.5, control group 2: 4.0). Significant differences were found between the test groups in VAS values and the number of analgesics taken (P < .001). Also, the lowest trismus and facial swelling values were detected in the 4 °C test group at all time points (P < .001).

CONCLUSION

In the impacted third molar surgery, the use of cooled saline irrigation during bone removal may be a simple, inexpensive, and effective method for reducing early postoperative complaints.

Effect of low-speed drilling without irrigation on osseointegration: an experimental study in dogs

OBJECTIVE

To study the early phases of osseointegration at implants installed in sites prepared with either high rotational speed with irrigation or low rotational speed without irrigation.

MATERIAL AND METHODS

After 3 months from tooth extraction, two implants were installed in one side of the mandible of twelve dogs. The osteotomies were prepared either at 60 rpm without irrigation or at 750 rpm with refrigeration. Biopsies were obtained after 4 and 8 weeks of healing, six animals each period for histological analyses.

RESULTS

After 4 weeks of healing, new bone percentage in contact with the implant surface (BIC%) was 46.6 ± 7.3% and 43.1 ± 6.8% at the low- and high-speed sites, respectively (p = 0.345). After 8 weeks of healing, the fractions increased to 60.0 ± 11.1% and 60.2 ± 6.2%, respectively (p = 0.753).

CONCLUSIONS

Implants installed in sites prepared using either low-rotational drilling without irrigation or high speed with irrigation presented similar amounts of osseointegration.

Effect of Guiding Sleeve Design on Intraosseous Heat Generation During Implant Site Preparation (In Vitro Study)

PURPOSE

To compare the effect of different designs of guiding sleeves on heat generation during implant surgery while using different cooling fluid temperatures.

MATERIAL AND METHODS

Temperature measurements were performed during guided implant site preparation in bovine rib samples using two K- type thermocouples at 2 mm and 8 mm depths. Three groups were tested according to guiding sleeve design: conventional cylindrical sleeve, open C-shaped sleeve, and modified cylindrical sleeve. Each group was irrigated with three fluid temperatures: 10°C, 15°C, and 20°C. The groups were compared using Kruskal Wallis test followed by post hoc comparisons with Bonferroni correction. The level of statistical significance was set at p = 0.05.

RESULTS

Surgical guides with conventional cylindrical sleeve design showed significantly higher heat generation during implant site preparation than guides with both the open C-shaped and the modified cylindrical sleeve designs at both 2mm and 8mm depths. The difference between C-shaped and modified cylindrical sleeves was not significant in any group. Using pre-cooled irrigation fluids (10°C and 15°C) reduced the generated heat; however, the differences within the same group were not statistically significant.

CONCLUSIONS

The use of a surgical guide with the conventional cylindrical sleeves led to higher heat generation than other sleeve designs, which might reach or near the critical threshold of bone thermal necrosis. Using surgical guides with open sleeves or modified cylindrical sleeves could be helpful in irrigation fluid delivery and decreasing the generated heat.

Evaluation of Different Osteotomy Drilling Speed Protocols on Cortical Bone Temperature, Implant Stability and Bone Healing: An Experimental Animal Study

The aim of this study was to measure the effect of drilling speed on heat generation in the cortical bone, on primary and secondary implant stability of implants and on early and late bone healing with micro-computed tomography (micro-CT). Sixty implants were placed in the iliac crest of six sheep in order to form 5 different drilling protocols: 50rpm without saline cooling, and 400rpm, 800rpm, 1200rpm and 2000rpm with saline cooling.  Simultaneous cortical bone temperature and primary stability at the time of placement; secondary stability and the ratio between relative bone and tissue volume (BV/TV) in 2D and 3D in micro-CT analysis were evaluated after 4 and 8 weeks. The 50rpm group had the highest cortical bone temperature and the longest operation duration with the highest primary stability. Slightly higher values of secondary stability (T2) and subsequent 2D and 3D BV/TV values were found in 1200 rpm with irrigation at 8 weeks. All groups had sufficient ISQ values at 8 weeks for loading although the micro-CT analysis showed varying percentages of bone tissue around implants. The influence of drill speed for implant osteotomy and its irrigation is minimal when it comes to changes in temperature of the cortical bone, primary and secondary implant stability and BV/TV.

Digitally planned root end surgery with static guide and custom trephine burs: A case report

INTRODUCTION

Apicoectomy is an endodontic surgical intervention that requires high precision. The computer-assisted static guided approach has proven to increase the precision of dental implantation in a significant manner. The authors sought to transfer this precision to root-end resection with the use of custom designed trephine burs manufactured specifically for use in targeted endodontic microsurgery.

METHODS

A set of custom bone trephines were designed and manufactured, then their digital models were integrated into an already existing implant surgical planning software, in cooperation with the software developer. Apicoectomy was performed in an actual case with the help of the new system.

RESULTS

It has become possible to plan root end removal in the virtual space and to manufacture 3D printed static surgical guides to help the execution of the surgery. A patient with persistent periapical lesion was successfully treated without complication. The 6-month follow-up found uneventful healing.

CONCLUSION

The presented system is a step toward a standardized digital system and workflow dedicated to guided endodontic surgery.

Healing at sites prepared using different drilling protocols. An experimental study in the tibiae of sheep

The aim of the experiment was to study the healing at implants installed in site prepared in bone type 1 using different rotation speeds and cooling strategies. The tibiae of twelve sheep were used as experimental sites. Two implant sites were prepared in each tibia using drills either at a high or a mixed speed under irrigation. At the mixed-speed sites, 60 rpm without irrigation were applied for the last drill, the countersink and during implant installation. Biopsies representing the healing after 1, 2, and 6 weeks were obtained and ground sections were prepared. At the histological analyses, after 1 week of healing, no new bone was found at both high- and mixed-speed sites. After 2 weeks of healing, small amounts of newly formed bone were observed in the cortical layer, reaching percentages of 3.6±3.0% at the mixed-speed sites, and of 2.2±1.5% at the high-speed sites. An irrelevant quantity of new bone was seen in the marrow compartments of a few specimens. After 6 weeks of healing, new bone was found in higher quantity, reaching in the cortical compartment 66.9±6.8% and 67.3±17.7% at the mixed- and high-speed sites, respectively. The respective percentages in the marrow compartment were 23.2±13.0% and 30.6±29.2%. No statistically significant differences between high- and mixed-speed groups were found. It was concluded that the use of the last drill and the installation of the implant with or without irrigation yielded similar bone healing and osseointegration.