Effect of Surgical Drill Guide on Heat Generated From Implant Drilling

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.

On the thermal impact during drilling operations in guided dental surgery: An experimental and numerical investigation

In recent years, a major development in dental implantology has been the introduction of patient-specific 3D-printed surgical guides. The utilization of dental guides offers advantages such as enhanced accuracy in locating the implant sites, greater simplicity, and reliability in performing bone drilling operations. However, it is important to note that the presence of such guides may contribute to a rise in cutting temperature, hence increasing the potential hazards of thermal injury to the patient's bone. The aim of this study is to examine the drilling temperature evolution in two distinct methods for 3D-printed surgical dental guides, one utilizing an internal metal bushing system and the other using external metal reducers. Cutting tests are done on synthetic polyurethane bone jaw models using a lab-scale automated Computer Numeric Control (CNC) machine to find out the temperature reached by different drilling techniques and compare them to traditional free cutting configurations. Thermal imaging and thermocouples, as well as the development of numerical simulations using finite element modeling, are used for the aim. The temperature of the tools' shanks experienced an average rise of 2.4 °C and 4.8 °C, but the tooltips exhibited an average increase of around 17 °C and 24 °C during traditional and guided dental surgery, respectively. This finding provides confirmation that both guided technologies have the capability to maintain temperatures below the critical limit for potential harm to bone and tissue. Numerical models were employed to validate and corroborate the findings, which exhibited identical outcomes when applied to genuine bone samples with distinct thermal characteristics.

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.

The 3D Printing and Evaluation of Surgical Guides with an Incorporated Irrigation Channel for Dental Implant Placement

Dental implant insertion requires the preparation of the implant bed via surgical drilling. During this stage, irrigation is essential to avoid thermal damage to the surrounding bone. Surgical guides enhance the accuracy of the implant site preparation, but they mask the drilling site, hampering coolant delivery. A variety of designs are aimed at improving the coolant access to the target site. Using standard dental implant simulation software, this paper presents an in-house design and 3D printing workflow for building surgical guides that incorporate a coolant channel directed toward the entry point of the burr. The proposed design was evaluated in terms of the bone temperature elevations caused by drilling performed at 1500 rpm, under an axial load of 2 kg, and irrigation with 40 mL/min of saline solution at 25 °C. Temperature measurements were performed on porcine femoral pieces, in the middle of the cortical bone layer, at 1 mm from the edge of the osteotomy. The mean temperature rise was 3.2 °C for a cylindrical sleeve guide, 2.7 °C for a C-shaped open-sleeve guide, and 2.1 °C for the guide with an incorporated coolant channel. According to a one-way ANOVA, the differences between these means were marginally insignificant (p = 0.056). The individual values of the peak temperature change remained below the bone damage threshold (10 °C) in all cases. Remarkably, the distribution of the recorded temperatures was the narrowest for the guide with internal irrigation, suggesting that, besides the most effective cooling, it provides the most precise control of the intraosseous temperature. Further studies could test different design variants, experimental models (including live animals), and might involve computer simulations of the bone temperature field.

Effect of Er:YAG Laser Exposure on the Amorphous Smear Layer in the Marginal Zone of the Osteotomy Site for Placement of Dental Screw Implants: A Histomorphological Study

The placement of dental screw implants typically involves the use of rotary techniques and drills to create a bone bed. This study explores the potential benefits of combining this method with an Er:YAG laser. Split osteotomies were performed on 10 jaws of euthanized domestic pigs (Sus scrofa domestica), with 12 mandibular implant osteotomies in each jaw, divided into 4 groups. In order to make a comprehensive assessment of the effect of Er:YAG lasers, histomorphological techniques were used to measure the reduction in amorphous layer thickness after Er:YAG laser treatment, both with and without the placement of dental screw implants from different manufacturers. Following bone decalcification and staining, the thickness of the amorphous layer was measured in four groups: Group A-osteotomy performed without Er:YAG laser treatment-had amorphous layer thicknesses ranging from 21.813 to 222.13 µm; Group B-osteotomy performed with Er:YAG laser treatment-had amorphous layer thicknesses ranging from 6.08 to 64.64 µm; Group C-an implant placed in the bone without laser treatment-had amorphous layer thicknesses of 5.90 to 54.52 µm; and Group D-an implant placed after bone treatment with Er:YAG laser-had amorphous layer thicknesses of 1.29 to 7.98 µm. The examination and photomicrodocumentation was performed using a LEICA DM1000 LED microscope (Germany) and LAS V 4.8 software (Leica Application Suite V4, Leica Microsystems, Germany). When comparing group A to group B and group C to D, statistically significant differences were indicated (p-value = 0.000, p < 0.05). The study demonstrates the synergistic effects and the possibility of integrating lasers into the conventional implantation protocol. By applying our own method of biomodification, the smear layer formed during rotary osteotomy can be reduced using Er:YAG lasers. This reduction leads to a narrower peri-implant space and improved bone-to-implant contact, facilitating accelerated osseointegration.

A Novel Irrigation System to Reduce Heat Generation during Guided Implantology: An In Vitro Study

The purpose of this in vitro study is to evaluate the effectiveness of incorporating a new irrigation system into a surgical guide and monitor its effect on heat generation during implant bed preparation. A total of 48 surgically guided osteotomies were performed on 12 bovine ribs divided into 4 groups, using different irrigation techniques: Group A (test) had entry and exit channels incorporated into the guide; Group B had a similar design with an entry channel only; Group C had conventional external irrigation; and Group D (control) had no irrigation. Heat generation during the osteotomies was measured using thermocouples placed at a depth of 2 mm and 6 mm. The lowest mean temperature was observed in Group A (22.1 °C at 2 mm and 21.4 °C at 6 mm), which was statistically significant when compared with Groups C and D (p < 0.001). Group A showed a lower mean temperature compared with Group B as well; however, it was statistically significant only at 6 mm depth (p < 0.05). In conclusion, the proposed surgical guide has significantly reduced heat generation during implant osteotomy compared to conventional external irrigation. The integration of an exit cooling channel can resolve limitations found in previously designed surgical guides such as debris blockage and can be easily incorporated into computer designing and 3D printing software.

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.

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.

Drilling- and withdrawing-related thermal effects of implant site preparation for ceramic and stainless steel twist drills in standardized bovine bone

INTRODUCTION

Excessive surgical trauma is believed to be among the most important causes for early implant losses. As thermal injury to the bone is not only dependent on the amount of generated heat but also on the tissue exposure time, and the greatest temperature increase was found within the withdrawing period, the entire osteotomy procedure with the parameters contributing to thermal damage is of particular clinical relevance. The aim of this study was to investigate the thermal performance of metal-based and ceramic implant drills regarding the temperature exposure time during the whole osteotomy process.

MATERIALS AND METHODS

This investigation consisted of 240 individual preparations in total, comprising two different drilling depths (10 and 16 mm), two irrigation methods (external and without irrigation), two implant drill materials (stainless steel and zirconia), and three consecutive drill diameters per material (2.0/2.2, 2.8, and 3.5 mm) with 10 identical repetitions. Real-time multichannel temperature measurement was conducted during automated drilling procedures in standardized bovine bone specimens.

RESULTS

The maximum temperature changes were highly associated with the time period of passive drill withdrawing (p ≤ 0.05), irrespective of drill material, drilling depth, or drill diameter. Statistically significant differences in temperature generation between stainless steel and ceramic drills were observed in irrigated testing sites at both drilling depths with smaller drill diameters (2.0/2.2 and 2.8 mm, p ≤ 0.05).

CONCLUSION

Results of this in vitro study could demonstrate a strong association between the highest temperature increase and the passive withdrawing time period in both investigated drill materials. Considering these findings and the resulting thermal bone damage due to the whole surgical procedure, high overall temperatures in combination with a prolonged heat exposure time may impact the future osseointegration process.

Oral and maxillofacial literature from Middle East: a bibliometric analysis and list of top-100 most cited articles

OBJECTIVES

The aim of this work is to perform a bibliometric analysis on Middle Eastern oral and maxillofacial surgery through years and to compare the data with previous studies. A list of the top 100 most cited articles was generated.

METHODS

A Pubmed bibliographic search for literature journals specialized in oral and maxillofacial surgery in the Middle East was performed. A graphic representation of authorship and keywords was created with VOSviewer. Mendeley and Microsoft Excel were used for tabulation and data visualization. A list of the top 100 most cited articles was created using Web of Science. Some statistical tests were performed with a 95% confidence interval, which was considered significant.

RESULTS

A total of 6,536 articles were retrieved in fifteen selected oral and maxillofacial journals. A moderate correlation between number of publications and total population (R = 0.6052), low correlation with area (R = 0.302291), and a negligible correlation with the Human Development Index (HDI) were found (R = 0.1747). A disparity can be seen in the number of publications by country, leaded by Turkey (46.30%), Israel and Iran (13.68% each). The more common studied topic was oral surgery (25.77%), maxillofacial trauma (16.13%) and oral pathology (10.25%).

CONCLUSIONS

A useful list of the top 100 most cited articles on oral and maxillofacial surgery from Middle East has been created. Middle East publications on oral and maxillofacial surgery can be considered high quality (IF = 1.879). Some issues on performing an adequate selecting of MeSH keywords were discussed.

Accuracy of Augmented Reality-Assisted Navigation in Dental Implant Surgery: Systematic Review and Meta-analysis

BACKGROUND

The novel concept of immersive 3D augmented reality (AR) surgical navigation has recently been introduced in the medical field. This method allows surgeons to directly focus on the surgical objective without having to look at a separate monitor. In the dental field, the recently developed AR-assisted dental implant navigation system (AR navigation), which uses innovative image technology to directly visualize and track a presurgical plan over an actual surgical site, has attracted great interest.

OBJECTIVE

This study is the first systematic review and meta-analysis study that aimed to assess the accuracy of dental implants placed by AR navigation and compare it with that of the widely used implant placement methods, including the freehand method (FH), template-based static guidance (TG), and conventional navigation (CN).

METHODS

Individual search strategies were used in PubMed (MEDLINE), Scopus, ScienceDirect, Cochrane Library, and Google Scholar to search for articles published until March 21, 2022. This study was performed in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines and registered in the International Prospective Register of Systematic Reviews (PROSPERO) database. Peer-reviewed journal articles evaluating the positional deviations of dental implants placed using AR-assisted implant navigation systems were included. Cohen d statistical power analysis was used to investigate the effect size estimate and CIs of standardized mean differences (SMDs) between data sets.

RESULTS

Among the 425 articles retrieved, 15 articles were considered eligible for narrative review, 8 articles were considered for single-arm meta-analysis, and 4 were included in a 2-arm meta-analysis. The mean lateral, global, depth, and angular deviations of the dental implant placed using AR navigation were 0.90 (95% CI 0.78-1.02) mm, 1.18 (95% CI 0.95-1.41) mm, 0.78 (95% CI 0.48-1.08) mm, and 3.96° (95% CI 3.45°-4.48°), respectively. The accuracy of AR navigation was significantly higher than that of the FH method (SMD=-1.01; 95% CI -1.47 to -0.55; P<.001) and CN method (SMD=-0.46; 95% CI -0.64 to -0.29; P<.001). However, the accuracies of the AR navigation and TG methods were similar (SMD=0.06; 95% CI -0.62 to 0.74; P=.73).

CONCLUSIONS

The positional deviations of AR-navigated implant placements were within the safety zone, suggesting clinically acceptable accuracy of the AR navigation method. Moreover, the accuracy of AR implant navigation was comparable with that of the highly recommended dental implant-guided surgery method, TG, and superior to that of the conventional FH and CN methods. This review highlights the possibility of using AR navigation as an effective and accurate immersive surgical guide for dental implant placement.

Heat Generation During Initial Osteotomy for Implant Site Preparation: An In Vitro Measurement Study

Introduction

Controlling temperature generation during implant site preparation is important to prevent implant early failure.

Aim

The present in vitro study aimed at measuring temperature variation generated during the initial osteotomy using both rotatory and piezo-surgical inserts.

Methods

Nine groups were defined according to drill and insert type, cooling volume (mL/min) and cooling temperature. A total of 315 implant site preparations were performed in an artificial bone sample and the temperature was measured using an infrared camera. Drills’ wear was assessed using scanning electron microscopy at baseline and after 10 and 35 utilizations.

Results

Piezo-surgical insert groups determined a temperature increase that was significantly higher than the one generated by rotatory drills groups (p < 0.001). When considering rotatory drills groups a temperature ≥ 40 °C was never recorded.

Conclusion

Lower saline temperature implied a significant temperature decrease (p < 0.001), while the increase in cooling volume did not imply a temperature decrease. The scanning electron microscopy analysis of the drills demonstrated that little drill wear occurred up to 35 utilization times.

Thermal changes during implant site preparation with a digital surgical guide and slot design drill: an ex vivo study using a bovine rib model

PURPOSE

In this study, we aimed to evaluate the degree of heat generation when a novel drill design with an irrigation slot was used with metal sleeve-free (MF) and metal sleeve-incorporated (MI) surgical guides in an environment similar to that of the actual oral cavity.

METHODS

A typodont with a missing mandibular right first molar and 21 bovine rib blocks were used. Three-dimensional-printed MF and MI surgical guides, designed for the placement of internal tapered implant fixtures, were used with slot and non-slot drills. The following groups were compared: group 1, MI surgical guide with slot drill; group 2, MI surgical guide with a non-slot drill; and group 3, MF surgical guide with a slot drill. A constant-temperature water bath at 36°C was used. The drilling was performed in 6 stages, and the initial, highest, and lowest temperatures of the cortical bone were measured at each stage using a non-contact infrared thermometer.

RESULTS

There were no temperature increases above the initial temperature in any drilling procedure. The only significant difference between the non-slot and slot groups was observed with the use of the first drill in the MI group, with a higher temperature in the non-slot group (P=0.012). When the heat generation during the first and the second drilling was compared in the non-slot group, the heat generation during the first drilling was significantly higher (P<0.001), and there was no significant difference in heat generation between the drills in the slot group.

CONCLUSIONS

Within the limitations of this study, implant-site preparation with the surgical guide showed no critical increase in the temperature of the cortical bone, regardless of whether there was a slot in the drill. In particular, the slotted drill had a cooling effect during the initial drilling.

Temperature Changes during Implant Osteotomy Preparations in Fresh Human Cadaver Tibiae, Comparing Straight with Tapered Drills

The success of osseointegration depends on many factors. With temperatures beyond a 47 °C threshold over 1 min, bone survival may be impaired. The purpose of the study was to evaluate, in fresh human cadaver tibiae, the temperature changes during osteotomy preparations using two straight and two tapered implant systems’ drills, external irrigation, and varying revolutions per minute (RPM). The tibiae from a fresh female cadaver were harvested bilaterally. Two tapered and two straight design drills were assessed. Two-hundred and forty osteotomies were prepared at 6 mm depth following the drill sequence of the manufacturers’ protocol for each drilling speed. Difference in temperature (ΔΤ) was calculated by subtracting the baseline from the maximum temperature (ΔT = T_max − T_base). Drill design and drill diameter, as independent variables or synergistically, had a significant effect on ΔΤ. Tapered drills: As the drill diameter increased, ΔΤ increased at all RPM. Straight drills: As the drill diameter increased, ΔΤ remained constant or slightly decreased at all RPM. Drill diameter and design had a significant effect on ΔΤ in human tibiae, which never exceeded the critical threshold of 47 °C. Tapered drills caused significantly greater heat production compared to straight drills.

Guided endodontic treatment in a region of limited mouth opening: a case report of mandibular molar mesial root canals with dystrophic calcification

BACKGROUND

The endodontic treatment of calcified root canals in molars is a challenging and time-consuming procedure. Even with the aid of a surgical microscope, the risk of root perforation is high, especially in the furcation area. The purpose of this study is to report the Computer-Aided-Design and Manufacturing (CAD-CAM) workflow, the innovative strategies for the template ideation, and the guided endodontic treatment of a mandibular molar with dystrophic calcification in the mesial root canals.

CASE PRESENTATION

A 58-year-old female patient, ASA I, was referred to endodontic treatment in the right first mandibular molar for prosthetic reasons. The mesiobuccal and mesiolingual canals appeared obliterated in the radiographic images. The absence of dental crown, tooth inclination, and the limited mouth opening of the region contributed to a poor visual reference of the tooth in the dental arch and the direction of the remaining lumens of the canals. Despite using surgical microscopy, the conventional technique led to the deviation of the mesiobuccal canal towards the furcation area. The obliteration of both mesial root canals was confirmed using the Cone Beam Computer Tomography. The clinical history associated with the tomography diagnosis was compatible with dystrophic calcifications in the pulp canals. The patient was submitted to an intra-oral scanning as well. The Digital Imaging and Communications in Medicine data (DICOM) were segmented. The Standard Tessellation Language (STL) files were processed following the CAD-CAM workflow, aiming to create two different endodontic templates with a new open design concept. The templates with open design allowed direct visualization of the operative field, irrigation, and dentin debris removal. The strategy of the guidance sleeves niche as half-cylinders allowed the drill insertion in a limited mouth opening region.

CONCLUSIONS

The digital planning and guided access permitted to overcome the case limitations and then re-establish the glide path following the original anatomy of the root canals. The guided endodontic represents a personalized technique that provides security, reduced risks of root perforation, and a significant decrease of the working time to access obliterated root canals even in the mesial root canal of mandibular molars, a region of limited mouth opening.

Thermal Effect of Operatory Room Temperature, Surgical Drill Diameter, and Temperature of Irrigants at Different Depths of Implant Site Preparation - Thermographic Analysis on Goat Mandible

Background:

Drilling of the implant site results in transient rise in temperature of the surrounding bone disrupting the bone healing process and implant stability. Overproduction of heat due to various factors at osteotomy site needs to be controlled as it hampers the final outcome of the procedure.

Purpose:

The purpose of this study was to evaluate various factors related to implant drills responsible for heat generation and temperature rise during osteotomy.

Materials and Methods:

A total of 64 bone specimens with dimensions of 15 mm × 15 mm were obtained from goat mandibles and were equally divided into Groups A and B with operating room temperature maintained at 25°C and 30°C, respectively. Osteotomies were performed using drills with diameters (4.2 mm and 5.6 mm) at various drilling depths (10 mm and 13 mm) with external saline irrigation temperatures (4°C and 25°C). Temperature change was recorded by laser thermometer.

Results:

The surgical drill depths, diameters, and room temperatures made no differences in temperatures at implant drilling sites whereas the temperatures of the irrigants provide sufficient heat control during drilling.

Conclusion:

Cooled saline provides beneficial effects in controlling the temperatures of osteotomy sites as compared to saline used at room temperature during implant site preparation.

Radiographic comparisons of crestal bone levels around implants placed with low-speed drilling and standard drilling protocols: Preliminary results

Background

The present study aimed to investigate the mean crestal bone loss (CBL) by placing implants using two different drilling-protocols, i.e., standard drilling with saline irrigation and low-speed drilling without saline irrigation.

Material and Methods

The patients were enrolled in the present study from a university teaching institute. Patients who fulfilled the inclusion criteria were randomly placed in two study groups: 1) control group: Standard drilling with saline irrigation and 2) test group: low-speed drilling without saline irrigation. The radiographic mean crestal bone loss (CBL) was evaluated at 3 months of follow-up before implant loading. Data analysis was performed using SPSS 20.0 (IBM product, Chicago, USA) and a p-value ≤ 0.05 was considered statistically significant.

Results

Sixteen patients (10 males and 6 females) participated in the study. Thirty Camlog®-screw-line implants were placed (15 implants per study group). After 3 months of follow-up, the means CBL of implants placed with standard drilling and low-speed drilling protocols were 1.01 ± 0.49 mm and 0.74 ± 0.62 mm, respectively. No statistically significant difference could be recorded between two groups (p = 0.206).

Conclusions

Dental implants placed with low-speed drilling without saline irrigation exhibited a similar CBL to implants installed with the standard drilling protocol. However, further randomised clinical trials are recommended to obtain stronger evidence and a better understanding of the effect of the low-speed drilling protocol without saline irrigation on mean CBL and long-term implant survival.

3D printed implant surgical guides with internally routed irrigation for temperature reduction during osteotomy preparation: A pilot study

OBJECTIVE

The purpose of this study was to test a novel through-the-guide means of irrigation in an in-vitro bovine bone model and to explore the method clinical applicability.

MATERIALS AND METHODS

Surgical guides were designed to fit over five fresh bovine samples. Control osteotomy sites were compared to experimental sites irrigated through a 3D printed surgical guide with customized channels that direct the coolant toward the interface of the alveolar crest and drill. Temperature was measured during surgery with thermocouples located at 3 and 6 mm from the crestal height of the bone, and with an infrared thermal camera taking direct temperature readings from a window cut into axial wall at 9 mm from the crestal height of the ridge.

RESULTS

Incorporation of routed irrigation significantly decreased heat generation, keeping temperature consistently below 47°C. A clinical case illustrates the method applicability using standard implant planning software, 3D printing technology, and regular implant armamentarium.

CONCLUSIONS

The in-vitro analysis shows that this method mitigates temperature increase caused by static surgical guide irrigation blockade at the osteotomy site. This technique can be incorporated in the surgical guide design using commercially available software and 3D printing technology and has immediate applications in practice.

CLINICAL SIGNIFICANCE

The in-vitro analysis shows that this method can significantly mitigate the temperature increase caused by static surgical guide irrigation blockade at the osteotomy site. This technique also has the advantage that it can be incorporated in the digital surgical guide design using commercially available software and 3D printing technology. The method has immediate applications in practice, and especially in the treatment of edentulism in esthetic zone where use of guided surgery for implant placement is crucial in obtaining consistent results.

Effect of different dental implant drilling template designs on heat generation during osteotomy - an in vitro study

OBJECTIVES

This in vitro study examined the effect of different implant drilling template designs on heat generation during osteotomy and on cooling fluid distribution.

MATERIAL AND METHODS

Five different template designs were investigated in a standardized setup against a control group and a negative control group: Occlusal-splint-design (OSD), OSD-covering, OSD-lateral opening, Bar design, and Orientation template. Pilot and one consecutive drill were run at 800 rpm with external irrigation and 2-kg load. Thermocouples recorded temperature changes at depths of 3, 6, and 9 mm in a bovine rib model. In the second experimental setup, the drill channel of one rib sample was perforated, and the irrigation volume passing through the drill channel was collected separately over time.

RESULTS

Following mean temperature rises occurred [in °C]: control, 4.9; negative control, 12; OSD, 5.6; OSD-covering, 4.7; OSD-lateral opening, 3.8; Bar design, 5.1; and Orientation template, 4.9. The highest temperature increases were found at a drilling depth of 6 mm (p < .006). The 2.2-mm drill resulted in a significantly higher temperature rise than the 2.8-mm drill (p < .001). The mean volume (ml/min) of irrigation through the drill channel was Control group-flow, 28.5; OSD, 4.1; OSD-covering, 2; OSD-lateral opening; 5.8; bar design, 4; and Orientation template, 24.1.

CONCLUSION

Within the limitations, it was shown that fully guided drilling templates reduce the amount of cooling liquid at the point of osteotomy. The template design had an influence on the effective volume of the cooling liquid. However, this did not seem to increase the intraosseous temperature significantly.

Infrared thermographic evaluation of rise in temperature with conventional versus trephine drills

Aim

To compare the rise in temperature using trephines over conventional ones during bone site preparation.

Setting and Design

An-vitro, evaluative study.

Materials and Methods

Twenty implant sites were prepared using pilot drill up to depth of 10 mm on bovine femoral bone. In first part, no irrigation was used. Five sites were prepared using conventional drill of 2.8 mm, and other five were prepared with help of trephine drills. On completion of each drill, infrared thermometer was used to measure temperature on both the drill tip and the shaft. The same procedure was repeated with bone immersed in saline.

Statistical Analysis Used

Student t test was used to evaluate the significance of difference.

Result

Study showed that the temperature rise at drill tip was significantly higher for trephine drill (52.98 ± 1.67 °C) than conventional drills (48.20 ± 0.67 °C), however the temperature difference in trephine and conventional drills was statistically insignificant.

Conclusion

The temperature increase was more distributed in conventional drills than trephine. Copious irrigation is thus mandatory for trephine drills. Intermittent drilling is preferred with conventional drills.

Thermal Evaluation by Infrared Thermography Measurement of Osteotomies Performed with Er:YAG Laser, Piezosurgery and Surgical Drill-An Animal Study

The bone healing process following osteotomy may vary according to the type of surgical instrumentation. The aim of the present in vivo study was to determine thermal changes of the bone tissue following osteotomies performed by Er:YAG laser ablation in contact and non-contact modes, piezoelectric surgery, and surgical drill using an infrared thermographic camera. For each measurement, the temperature before the osteotomy-baseline (Tbase) and the maximal temperature measured during osteotomy (Tmax) were determined. Mean temperature (ΔT) values were calculated for each osteotomy technique. The significance of the difference of the registered temperature between groups was assessed by the ANOVA test for repeated measures. Mean baseline temperature (Tbase) was 27.9 ± 0.3 °C for contact Er:YAG laser, 29.9 ± 0.3 °C for non-contact Er:YAG laser, 29.4 ± 0.3 °C for piezosurgery, and 28.3 ± 0.3 °C for surgical drill. Mean maximum temperature (Tmax) was 29.9 ± 0.5 °C (ΔT = 1.9 ± 0.3 °C) for contact Er:YAG laser, 79.1 ± 4.6 °C (ΔT = 49.1 ± 4.4 °C) for non-contact Er:YAG laser, 29.1 ± 0.2 °C (ΔT = −0.2 ± 0.3 °C) for piezosurgery, and 27.3 ± 0.4 °C (ΔT = −0.9 ± 0.4 °C) for surgical drill. Statistically significant temperature changes were observed for the non-contact laser. The results of the study showed beneficial effects of the osteotomy performed by the Er:YAG laser used in the contact mode of working as well as for piezosurgery, reducing the potential overheating of the bone tissue as determined by means of infrared thermography.

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.

Effect of guide sleeve material, region, diameter, and number of times drills were used on the material loss from sleeves and drills used for surgical guides: An in vitro study

STATEMENT OF PROBLEM

How material loss from sleeves and drills is affected when different guide sleeve materials and different sizes of implant drills are used for different regions of surgical guides is unclear.

PURPOSE

The purpose of this in vitro study was to compare the amount of material loss from different guide sleeves (zirconia and cobalt-chromium) and drills of different diameters during osteotomy preparation in different regions.

MATERIAL AND METHODS

Three tooth-supported surgical guides with sleeve holes positioned in the first premolar and second molar sites were prepared. Guide sleeves (Ø 2.20 mm, 3.40 mm, and 4.05 mm) were milled from zirconia (n=60) and cobalt-chromium (n=60) blocks. A total of 12 titanium nitride-coated stainless steel twisted drills (n=6 per sleeve material) of different diameters (Ø 2.00, 3.20, 3.85 mm) were used with corresponding sleeves during the drilling. The weight loss from the drills and the volume loss from the guide sleeves after drilling were analyzed by using multiple linear mixed effect models (α=.05).

RESULTS

According to the 4-way ANOVA for volume loss from sleeves, no significant interaction was found among the 4 main effects (number of times a drill was used, region, diameter, and material), but interactions between the number of times a drill was used and diameter (P=.001) and between the number of times the drill was used and material were significant (P<.001). For weight loss from the drills, a significant interaction was detected between the number of times the drill was used and diameter (P=.024).

CONCLUSIONS

Less sleeve material was lost when zirconia sleeves were used. All sleeves had more material loss in the molar region than in the premolar region. The diameter had varying effects on the amount of material loss from drills and sleeves. The sleeve material and the region did not affect the material loss from drills.

Intra-osseous heat generation during implant bed preparation with static navigation: Multi-factor in vitro study

OBJECTIVES

To compare the intra-osseous temperature reached during bone drilling for dental implant placement using open versus closed static surgical guides and evaluate the influence of bone density, osteotomy drilling depth, and irrigation fluid temperature.

MATERIAL AND METHODS

960 osteotomies were performed with 2 mm pilot drills in 16 solid rigid polyurethane foam blocks. Two main variables were considered: the guide type (open or closed guide) and bone density (hard (D1) or soft (D4). The blocks were divided into four groups according to the type of surgical template and bone density as follows: group one: closed guide and hard bone; group two: open guide and hard bone; group three: closed guide and soft bone; and group four: open guide and soft bone. A combination of different experimental conditions was used, including different bone osteotomy depths (6 or 13 mm) and irrigation fluid temperatures (5°C or 21°C).

RESULTS

The highest mean temperature was found in group one (28.29 ± 4.02°C). In the soft bone groups (three and four), the mean maximum temperature decreased compared to groups one and two (dense bone) and was always higher with closed guides (23.38 ± 1.92°C) compared to open guides (21.97 ± 1.22°C) (p < .001). The osteotomy depth and irrigation fluid temperature also significantly influenced the bone temperature (p < .001), especially in hard bone.

CONCLUSIONS

The greatest heat generation was observed in high-density bone. The final intra-bone temperature was about 1°C higher with a closed static surgical guide than with an open guide. The heat generation in osteotomy sites was substantially reduced by cooling the irrigation fluid to 5°C.

Thermal exposure of implant osteotomies and its impact on osseointegration-A preclinical in vivo study

OBJECTIVES

Thermal and mechanical stresses during osteotomy preparation can impair implant osseointegration. This study investigated implant osseointegration following the measurement of temperature exposure during osteotomy drilling, varying drill design, sequence, and drill wear.

MATERIALS AND METHODS

36 tapered implants were placed in a mandibular minipig model after guided drilling of implant osteotomies using 4 different groups: (1) control drills with a conservative, sequential drilling sequence, (2) control drills using a shortened drill sequence (PF), (3) novel test drill displaying an optimized drill design and surface treatment, PF, and (4) aged test drill, PF. Intraosseous temperatures during drilling were measured using a temperature probe. BIC, fBIC, and tissue reactions were histomorphometrically derived after 2 and 8 weeks of healing.

RESULTS

Compared to control drills (1) or (2), test drills (3) resulted in significantly lower maximum temperatures ((35.4 (CI 30.2-40.5)°C vs. (46.5 (CI 41.0-52.0)°C, p = .0021)) and shorter drill times ((4.5 (CI 1.6-7.3)sec vs. 10.3 (7.3-13.4)sec). Lower osteotomy temperature values and shorter drill times corroborated with significantly higher BIC after 2 and 8 weeks healing for the test (3) compared to control groups (2) (2 weeks: (44.9 (CI 34.1-55. 7)% vs. (31.3 (CI 20.5-42.2)%, p = <.0001 and 8 weeks: (73.7 ( CI 64.2-83.2)% vs. (66.2 (CI 57.0-75.4)%, p = <.0455).

CONCLUSION

The improved osseointegration of implants placed after osteotomy preparation with novel test drills using a shortened drill sequence compared to standard drills and conventional drill protocols might be attributed to more favorable thermal profiles and less mechanical stress exerted on the bone surrounding the implant osteotomy.

Bone Temperature Variation Using a 3D-Printed Surgical Guide with Internal Irrigation

Bone overheating is a possible cause of implants early failure. When a surgical guide is used, the risk of heat injury is greater due to the reduced efficacy of the irrigation. The aim of this ex vivo study was to evaluate the effect of an additional built-in irrigation on bone temperature variation during implant osteotomy. Twelve bovine ribs were used. Cone beam computerized tomography (CBCT) was performed and a 3D-printed surgical guide with additional built-in irrigation tubes was produced for each rib. A total of 48 osteotomies were prepared, to compare the supplementary internal irrigation system (Group A) with external irrigation alone (Group B), no irrigation (Group C) and with free-hand surgery with external irrigation (Group D). Temperature was measured by three thermocouples placed at depths of 1.5, 7, and 12 mm. The largest temperature variation at each thermocouple showed median values of 3.0 °C, 1.9 °C, and 2.3 °C in Group 1; 2.3 °C, 1.7 °C, and 0.9 °C in Group 2; 3.2 °C, 1.6 °C, and 2.0 °C in Group 3; 2.0 °C, 2.0 °C, and 1.3 °C in Group 4, respectively. No differences were found among the four groups. In general, the highest temperature increase was observed with the use of the first drill (cortical perforator). Post-experimental CBCT revealed the presence of radiopaque material clogging the aperture of the internal irrigation channels. Additional internal irrigation was not found to significantly contribute to decrease bone temperature in this ex vivo setting.

Thermal effects of various drill materials during implant site preparation-Ceramic vs. stainless steel drills: A comparative in vitro study in a standardised bovine bone model

OBJECTIVES

The aim of this study was to evaluate thermal effects of ceramic and metal implant drills during implant site preparation using a standardised bovine model.

MATERIAL AND METHODS

A total of 320 automated intermittent osteotomies of 10- and 16-mm drilling depths were performed using zirconium dioxide-based and stainless steel drills. Various drill diameters (2.0/ 2.2, 2.8, 3.5, 4.2 mm ∅) and different cooling methods (without/ with external saline irrigation) were investigated at room temperature (21 ± 1°C). Temperature changes were recorded in real time using two custom-built multichannel thermoprobes in 1- and 2-mm distance to the osteotomy site. For comparisons, a linear mixed model was estimated.

RESULTS

Comparing thermal effects, significantly lower temperatures could be detected with steel-based drills in various drill diameters, regardless of drilling depth or irrigation method. Recorded temperatures for metal drills of all diameters and drilling depths using external irrigation were below the defined critical temperature threshold of 47°C, whereas ceramic drills of smaller diameters reached or exceeded the harmful temperature threshold at 16-mm drilling depths, regardless of whether irrigation was applied or not. The results of this study suggest that the highest temperature changes were not found at the deepest point of the osteotomy site but were observed at subcortical and deeper layers of bone, depending on drill material, drill diameter, drilling depth and irrigation method.

CONCLUSIONS

This standardised investigation revealed drill material and geometry to have a substantial impact on heat generation, as well as external irrigation, drilling depth and drill diameter.

Influence of Drilling Technique on the Radiographic, Thermographic, and Geomorphometric Effects of Dental Implant Drills and Osteotomy Site Preparations

The aim of this comparative study is to analyze the influence of drilling technique on the radiographic, thermographic, and geomorphometric effects of dental implant drills and osteotomy site preparations. One hundred and twenty osteotomy site preparations were performed on sixty epoxy resin samples using three unused dental implant drill systems and four drilling techniques performed with a random distribution into the following study groups: Group A: drilling technique performed at 800 rpm with irrigation (n = 30); Group B: drilling technique performed at 45 rpm without irrigation (n = 30); Group C: drilling technique performed at 45 rpm with irrigation (n = 30); and Group D: drilling technique performed at 800 rpm without irrigation (n = 30). The osteotomy site preparation morphologies performed by the 4.1 mm diameter dental implant drills from each study group were analyzed and compared using a cone beam computed tomography (CBCT) scan. The termographic effects generated by the 4.1 mm diameter dental implant drills from each study group were registered using a termographic digital camera and the unused and 4.1 mm diameter dental implant drills that were used 30 times from each study group were exposed to a micro computed tomography (micro-CT) analysis to obtain a Standard Tessellation Language (STL) digital files that determined the wear comparison by geomorphometry. Statistically significant differences were observed between the thermographic and radiographic results of the study groups (p < 0.001). The effect of cooling significatively reduced the heat generation during osteotomy site preparation during high-speed drilling; furthermore, osteotomy site preparation was not affected by the wear of the dental implant drills after 30 uses, regardless of the drilling technique.

Guided Implant Placement Using an Internally Cooling Surgical Template: A Technical Note

Cooling irrigation during implant bed preparation is mandatory to avoid overheating. Due to the surgical guide design, external cooling systems do not reach the point of entry of the implant burr. Here, a new technique for irrigation during guided implant surgery for direct rinse of the burr is described. Using computer-aided design/computer-aided manufacturing additive technology, a pin of a cooling pipe was designed and implemented in a surgical guide template. The implant bed preparation was performed while the cooling pipe was connected to the surgical guide. During surgery, the irrigation solution was directly rinsing the burr at the point of entry through the irrigation channel. The use of a cooling surgical guide seems to improve the cooling of the bone during implant bed preparation. This might lead to less thermal effect of bone cells. However, systematic studies are needed to confirm the observations of the presented case report.

Design and Characterization of an Actuated Drill Mockup for Orthopedic Surgical Training

Haptic feedback in virtual reality-based trainers for surgical bone drilling is mostly provided via impedance-controlled haptic devices. Due to this, the displayable maximum stiffness is limited. In addition, vibration feedback is often only of reduced fidelity. To overcome these shortcomings, we have developed a hand-held, actuated admittance-controlled drill mockup, comprising enhanced kinesthetic and tactile feedback. This article reports on design and characterization of the device, and highlights its use for training. Kinesthetic feedback is provided through haptic augmentation, employing a ball-screw mechanism acting on a retractable drill-bit. Feedback computation relies on admittance control, thus allowing for stable display of very high resistance forces, and thus material stiffness, which cannot be achieved with standard impedance-control approaches. For the tactile mechanism, a modified linear vibration actuator is directly attached to the mockup handle, improving signal transmission. Tactile feedback computation is based on an extension of a previously proposed power spectral density control method. Frequency-specific gains are adjusted in real-time, compensating for differences between desired and measured vibrations. The performance of the device is characterized in several experiments, including comparisons to drilling with a real drill into artificial bone samples. In addition, several user studies have been carried out. We illustrate the capability of the mockup to render bone samples with different material layer stiffness and thickness. Moreover, we show that the mockup system allows for the same training effect as when rehearsing with a real drill.

In-vitro assessment of bone viability with different implant drill speeds

The success of implant osseointegration is clearly impacted by the heat produced throughout the implant osteotomy site preparation. Bone necrosis of the implant bed should be prevented to maintain a stable osseointegration process. The objective of this experiment was to validate the impact of implant drill speed on the bone from the point of view of heat generation; a second objective was to evaluate viability of the osteotomised implant sites in rabbits histologically. Twenty healthy adult rabbits, were randomly categorised into 4 groups; 3 bony osteotomies in the 3 mm, 3.5 mm and 4 mm diameters of the femur were made in each rabbit. Variable speeds were used for the 3 diameters as follow: Group I: speed 1000 rpm, Group II: speed 1500 rpm, Group III: speed 2000 rpm. A combination of speed 2000 rpm for the small diameter drills and the last large diameter with speed 1000 rpm was used in Group IV. The temperature changes were recorded. After the operation, the rabbits were euthanised and the bony samples were taken for histological evaluation. In group III and Group IV, histological analysis demonstrated more bone viability compared to other groups. Furthermore, heat analysis revealed significant differences between group III, Group IV and the other groups with less heat produced with greater speeds compared with lower speeds. Drilling with higher speed in dense bone with irrigation produces less heat and maintains more bone viability compared with lower speed. In addition, increased drill diameter with the same speed or with increased speed generates less heat compared with smaller diameters.

Clinical and radiographic evaluation of implants placed with fully guided versus partially guided tissue-supported surgical guides: A split-mouth clinical study

STATEMENT OF PROBLEM

The effect of placing implants by using a fully guided protocol versus a partially guided protocol on the peri-implant soft and hard tissues is unclear. C-shaped guide holes are often used; however, their effect on drilling and peri-implant tissues has not been thoroughly investigated.

PURPOSE

The purpose of this split-mouth clinical study was to clinically and radiographically evaluate peri-implant soft and hard tissues after implant placement by using fully guided versus partially guided surgical guides with cylindrical versus C-shaped guide holes.

MATERIAL AND METHODS

Adopting an 80% power of the study in calculating sample size, a total of 48 implants were placed in the mandibular interforaminal area of 12 edentulous participants. Implants were randomly divided into 2 groups: a fully guided group comprising 24 implants placed on 1 side by using a fully guided protocol and a partially guided group comprising 24 implants placed on the other side of the same participant by using a partially guided protocol. Each group was further subdivided into 2 subgroups: cylindrical, including 12 implants placed through cylindrical guide holes, and C-shaped (12 implants) placed through C-shaped guide holes. All participants were clinically evaluated in terms of a modified plaque index, modified gingival index, peri-implant probing depth, and probing attachment level at 2, 4, and 6 months. Implant stability, marginal bone level, and bone density were then evaluated immediately after implant placement at 2, 4, and 6 months.

RESULTS

No statistically significant differences were found in the plaque index (P=.927), modified gingival index (P=.916), probing depth (P=.832), probing attachment level (P=.096), implant stability (P=.338), bone level (P=.063), or bone density (P=.390) between the fully guided protocol and partially guided protocol.

CONCLUSIONS

The soft and hard tissues surrounding the implants placed by using fully guided surgical guides were clinically comparable with those placed by using partially guided surgical guides whether the guiding holes were cylindrical or C-shaped.

Comparative Analysis of Bone Tissue Temperature during Implant Preparation with Variable Drilling Parameters: In Vitro Study

Purpose. The aim of this work was to compare the temperature fluctuations that occur during the development of the implant bed using three different implant systems and the impact on their value of cooling method and rotational speed of drill. Material and Methods. As a model of the human jaw due to the analogy of bone structure and hardness, pig ribs were used. Drills from three different implant systems were used in the study: Straumann® (Straumann GmbH, Basel, Switzerland), AnyRidge® (Megagen Implant Co., Ltd., Daegu, South Korea), and Osstem (OSSTEM IMPLANT CO., LTD., Seoul, South Korea). The sequence of three successive drills was given—from pilot drill to final drill. For each system, a group with two water cooling methods, without cooling, and three different speed ranges, 800, 1200, and 1500 rpm, and their effect on temperature fluctuations was evaluated. The temperature was measured by thermography. Results. The highest temperature increases were noted during preparation with pilot drills. The maximum temperature (50.8°C) was noted for the AnyRidge pilot drill at 1500 rpm without cooling. When cooling with physiological saline, none of the applied drills exceeded 28°C. Significant differences between lack of cooling and cooling with saline at 20°C and 3°C have been demonstrated. During preparation with cooling, the difference between the times of the maximum temperature achievement was observed between AnyRidge® and Osstem (2.6 vs. 1.6 s, p=0.004). Conclusion. The experiment showed that the drills of the tested implant systems differed in the amount of heat generated during operation. The temperature of the cooling solution and the rotational speed applied have an influence on its amount.

Comprehensive analysis on orthopedic drilling: A state-of-the-art review

Bone drilling is a well-known internal fixation procedure to drill a hole, fixing the bone fragments to reduce the susceptibility of permanent paralysis. The success of bone drilling is evaluated based on the extent of osteonecrosis in terms of heat generation, tissue damage, quality of hole, and drilling forces. The appropriate control of cutting conditions, drill geometric parameters, and bone-specific parameters offer bone drilling a viable solution through conventional and non-conventional drilling techniques. The majority of the published research work considers only limited parameters and tries to optimize the drilling parameters and performance measures. However, bone drilling involves numerous conventional and non-conventional drilling parameters and technologies. In order to develop a better understanding of all the studied parameters and performance measures, there is a dire need to develop a framework. The key objective of this review study is to establish a hierarchy of the framework by collecting almost all the parameters studied until now and addressed the relationship between parameters and performance measures to diminish the controversies in the published literature. Therefore, this framework is novel in nature, organizing all the parameters, performance measures, logical comparisons, and limitations of studies. This holistic review can help medical surgeons and design engineers to understand the complicated relationship among parameters and performance measures associated with this state-of-art technologies. Also, modeling, simulations, and optimization techniques are included to explore the application of such techniques in recent advancements in orthopedic drilling.

Temperatures generated during implant site preparation with conventional drilling versus single-drill method: an ex-vivo human mandible study

BACKGROUND

Bone overheating during osteotomy is a potential cause of necrosis and consequent failure of dental implant osseointegration. The aim of this study is to identify any differences between conventional osteotomy with drills of increasing size and the use of a single drill in terms of the temperature increase in the bone during implant site preparation.

METHODS

Thirty-eight implant sites were prepared in ex vivo human mandibles, 19 using the conventional method with drills of increasing diameter (group A) and 19 using a single-drill method (group B), with no irrigation in either procedure. An infrared thermometer was used to measure the temperature difference (T°) induced by the drills at each site. Student's t-test (with P<0.05) was used to compare the temperature increase induced by the last drill in group A, and by the single drill in group B.

RESULTS

The mean ΔT° in group A was 0.64 °C, while in group B it was 1.47 °C. The difference between the temperatures obtained in the two groups was statistically significant (P=0.0073).

CONCLUSIONS

In statistical terms, the two methods differ significantly in the temperature increase induced by the drilling procedure, but this difference is clinically irrelevant.

Computer-Guided Dental Implant Treatment of Complete Arch Restoration of Edentulous and Terminal Dentition Patients

The treatment of completely edentulous or soon-to-be completely edentulous dental arches with complete-arch fixed denture restorations, supported by dental implants, are some of the more complicated patient cases in oral and maxillofacial surgery and prosthodontics. This article discusses the use of digital technologies, computerized tomographic (CT) guided planning software applications, and surgical guides in treating these complex dental implant patient cases. A discussion of the nuances and workflows of different types of treatments are provided. The importance of experience and a multi-disciplinary team approach is emphasized.

Evaluation of Surgical Bur Deformation and Bone Surface Roughness After Multiple Uses

PURPOSE

The aim of the present in vitro study was to microscopically evaluate and describe the deformation of Lindeman surgical burs and the bone surface roughness after repeated osteotomies and sterilization cycles.

MATERIALS AND METHODS

Twenty-one Lindeman surgical burs were analyzed under scanning electron microscopy (SEM) to evaluate the damage of the bur's integrity after 0, 1, 3, 5, 7, or 9 osteotomies on bovine ribs. Eighteen bone specimens were obtained after osteotomy for roughness analysis using profilometry. One-way analysis of variance was used to compare the mean roughness values across the experimental groups, and P ≤ .05 was considered to indicate statistical significance.

RESULTS

Representative SEM images illustrated that all analyzed burs presented with some type of deformation at both the tip and the body, even after their first use. The mean roughness values were independent of the number of uses (P > .05); however, the standard deviation increased with the number of uses of the burs.

CONCLUSIONS

These results suggest that even after their first use, rotatory surgical burs will have some type of deformation and that their cutting efficiency on the bone will vary and will be difficult to predict.

Comparison of heat generation between guided and conventional implant surgery for single and sequential drilling protocols-An in vitro study

OBJECTIVES

The aim of this in vitro study was to compare the heat generation during guided osteotomy preparation (GOP) with that of a conventional approach (CA) for a single and sequential drilling protocol.

METHODS

Temperature measurements were performed during standardized osteotomy preparations in polyurethane foam blocks with an infrared camera. The four groups included single and sequential drilling with and without the use of a surgical guide. In the first group (single CA) and the second group (single GOP), only the final drills diameters were applied once. In the third group (sequential CA) and the fourth group (sequential GOP), two to four drills with increasing diameters were applied. Guided and conventional as well as single and sequential drilling were compared using a one-way ANOVA with Tukey post hoc test. The level of statistical significance was set at α = 0.05.

RESULTS

Guided osteotomy preparation showed statistically significant higher temperatures than CA for the 2.2 mm, the 3.5 mm, and the 4.2 mm drill (p = 0.032, p = 0.005 and p < 0.001, respectively). Sequential drilling led to higher heat generation and longer duration of latent heat than single drilling. For all drilling procedures, the duration of heat exposure over critical temperature was less than 1 min, except for the sequential GOP drilling protocol with the 4.2 mm drill (76 s).

CONCLUSIONS

Guided drilling requires specific attention to heat development. When guided implant surgery is performed, a single drilling procedure could alleviate heat production compared to a sequential procedure.

Intraosseous Heat Generation During Osteotomy Performed Freehand and Through Template With an Integrated Metal Guide Sleeve: An In Vitro Study

OBJECTIVE

To investigate drill wear and consequent intraosseous temperature elevation during freehand and guided bone drilling, with attention to the effect of metal-on-metal contact during guided drilling.

MATERIALS AND METHODS

Osteotomies were performed on bovine ribs, with 2.0 mm diameter stainless steel drill bits of the SMART Guide System, under 3 sterilization protocols, at 800, 1200, 1500, and 2000 rpm. Sterilization was performed after every 3 drilling. Temperature was measured after every 30 drilling.

RESULTS

The studied contributing factors had a cumulative effect, and each contributed significantly to temperature elevation. Whether guide use led to a near-necrotic (47°C) temperature increment depended largely on the applied sterilization protocol.

CONCLUSION

The metal sleeve is a significant contributing factor to heat generation during guided osteotomy, but its effect can be offset by keeping the other studied factors under control.

Effect of 2 Different Drilling Speeds on the Osseointegration of Implants Placed With Flapless Guided Surgery: A Study in Rabbits

OBJECTIVE

The aim of this study was to evaluate the influence of the drilling speed on bone healing and the osseointegration of implants placed with a guided flapless surgical technique in rabbit tibias.

METHODS

For the evaluation of bone healing, a total of 30 perforations (defects) were made in both tibias of 15 rabbits using 2 different drilling speeds (1500 rpm-control group; 50 rpm-test group). The regeneration of bone tissue in the surgical sites was evaluated at 0, 7, and 14 days. For the evaluation of implant osseointegration, another 15 rabbits underwent drilling in both tibias for implant placement. Thirty implants (3.75 × 10 mm) were placed to evaluate osseointegration at 4, 8, and 12 weeks after surgery.

RESULTS

Both groups showed a progressive healing of the defect, which involved the complete closure of the perforation. The osseointegration occurred in all groups with no statistically significant differences in the assessment of the osseointegration between the groups.

CONCLUSION

In the experimental models used, the drilling speed does not prejudice the pattern of bone healing and osseointegration of implants placed with guided flapless surgery.

EXPERIMENTAL STUDY ON THE EFFECT OF DRILL QUALITY ON BONE TEMPERATURE IN DRILLING

Bone drilling is widely performed in orthopedics for fixation and reconstruction of bone. In bone drilling, a hard metallic drill penetrates into the bone tissue which may cause trauma. Shear deformation of the bone material and friction between the drill and bone may induce elevated temperature in bone tissue. Temperature above a certain level may seriously harm the tissue, leading to several postoperative complications. The purpose of the current study is to measure and compare temperature in bone drilling using sharp and worn drill. Drilling tests were performed on cortical bone obtained from femoral shaft of a cow. A parametric study was conducted to quantify bone temperature using a range of drilling speeds and feed rates using drills having sharp and worn cutting edges with and without cooling environment. The temperature was measured using thermocouples, and wear of the cutting edges of the drill was measured using a scanning profilometer. Experimental results demonstrated lower temperature in bone using a sharp drill compared with a worn drill for similar drilling conditions. The bone temperature was found to rise with drill rotational speed, rate of penetration and size of the drill with and without cooling. Blunt drills were found more crucial for inducing thermal necrosis in bone.

Comparative Study on Early Osseointegration of Implants According to Various Drilling Speeds in the Mandible of Dogs

PURPOSE

This study evaluated the effect of drilling speed on early bone healing in the mandible of dogs.

MATERIAL AND METHODS

Six dogs were selected, and mandibular premolars and molars were extracted. After 2 months, 3 hydroxyapatite-surfaced fixtures were implanted with drilling speeds of 50, 800, and 1200 rpm on the right side first and then on the left side after 2 weeks. Implant stability quotient (ISQ) was measured on insertion, after 2 and 4 weeks.

RESULTS

Based on the ISQ measurement, the 1200-rpm group showed a higher value than the 50-rpm group at 2 weeks and 4 weeks (P < 0.05). New bone formation around the implant was highest for the 800-rpm group at 2 weeks and the 1200-rpm group at 4 weeks. The bone-implant contact of the superior half of the alveolar bone was highest for the 800-rpm group at 2 weeks and the 1200-rpm group at 4 weeks. There was no statistically significant difference.

CONCLUSION

This study suggests that 50, 800, and 1200 rpm are drilling speeds which can expect favorable outcome, yet, higher drilling speed presented overall the best biological responses.

Comparison of peri-implant bone loss between conventional drilling with irrigation versus low-speed drilling without irrigation

Background

To compare the technique of high speed drilling with irrigation and low speed drilling without irrigation in order to evaluate the success rate and peri-implant bone loss at 12 months of follow-up.

Material and Methods

A randomized, controlled, parallel-group clinical trial was carried out in patients requiring dental implants to rehabilitate their unitary edentulism. Patients were recruited from the Oral Surgery Unit of the University of Valencia (Spain) between September 2014 and August 2015. Patients who met the inclusion criteria were randomized to two groups: group A (high-speed drilling with irrigation) and group B (low-speed drilling without irrigation). The success rate and peri-implant bone loss were recorded at 12 months of follow-up.

Results

Twenty-five patients (9 men and 16 women) with 30 implants were enrolled in the study: 15 implants in group A and 15 implants in group B. The mean bone loss of the implants in group A and group B was 0.83 ± 0.73 mm and 0.62 ± 0.70 mm, respectively (p > 0.05). In the maxilla, the bone loss was 1.04 ± 0.63 mm in group A and 0.71 ± 0.36 mm in group B (p > 0.05), while bone loss in the mandible was 0.59 ± 0.80 mm in group A and 0.69 ± 0.77 mm in group B (p > 0.05). The implant success rate at 12 months was 93.3% in group A and 100% in group B.

Conclusions

Within the limitations of the study, the low-speed drilling technique presented peri-implant bone loss outcomes similar to those of the conventional drilling technique at 12 months of follow-up.

Key words:Low-speed without irrigation, drilling technique.