Low-speed drilling without irrigation versus conventional drilling for dental implant osteotomy preparation: a systematic review

Effect of osteotomy strategy on primary stability and intraosseous temperature rise: an ex-vivo study

BACKGROUND

Primary stability is a perquisite for achieving successful osseointegration. Additionally thermal effect of implant bed preparation plays an important role in success of a dental implant. This ex vivo study was conducted to compare one step implant specific osteotomy and conventional osteotomy in terms of primary stability and thermal changes during surgery.

METHODS

Forty eight implants were inserted into the sheep iliac crest bones each with a safe distance to each other and divided into six groups. In two of the groups implant specific osteotomy and in the remaining 4 groups conventional osteotomy was performed. In the groups, the primary stability of the trioval implants designed for the implant specific osteotomy were compared with the oval active threaded implants. The two osteotomy methods were also compared. Additionally the thermal changes during the two osteotomy methods were compared using a double-channel temperature monitoring device.

RESULTS

Statistically significant differences (P <.05) were observed between the stability groups and the thermal evaluation groups (P <.05). Implant specific osteotomy revealed significantly higher stability than the conventional osteotomy (P <.001). Osteotomy without irrigation caused significantly higher thermal changes than the conventional osteotomy wit irrigation (P <.001).

CONCLUSION

Although the implant specific osteotomy reveals better primary stability, it causes higher temperature during drilling. However, since this increase is within the limits and doesn't cause a risk in terms of osseointegration, it may be used safely in clinical practice.

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.

Effects of Repeated Use and Sterilization on the Wear of Zirconia Implant Drills: A SEM-Based Analysis

OBJECTIVES

This study evaluated the effects of repeated use and sterilization on the wear and cutting-edge integrity of zirconia implant drills.

MATERIALS AND METHODS

Sixty zirconium dioxide drills (Z-Systems AG) with diameters of 2.3, 3.75, and 4.25 mm were tested. Drilling was performed in porcine mandibular bone under standardized conditions: 800 rpm, 50 Ncm torque, and 20 N axial pressure. Drills were divided into two groups: Group 1 (sterilized but unused) and Group 2 (30 drilling cycles with reprocessing). Wear was assessed using scanning electron microscopy (SEM) at 1000x magnification, applying a three-grade scoring system. Statistical analysis was performed using the Mann-Whitney U test (p < 0.05).

RESULTS

Drills subjected to 30 cycles showed significantly higher wear grades (Grade 2-3) compared to unused drills (Grade 0-1) (p < 0.001). The mean wear grades increased from 0.3 to 2.6 for 2.3 mm, from 0.4 to 2.7 for 3.75 mm, and from 0.2 to 2.7 for 4.25 mm drills. Effect sizes (r = 0.88-0.90) confirmed a strong relationship between repeated use and wear.

CONCLUSIONS

Zirconia drills show significant wear after 30 cycles. Although they offer potential as an alternative to steel drills, further research is needed to optimize cost-effectiveness and clinical durability.

CLINICAL TRIAL REGISTRATION

Not applicable.

Microscopic Analysis and Evaluation of Thermal Elevation and Wear of Drills for Implant Site Preparation: An In Vitro Study

Drilling for implant site preparation generates heat, which can cause bone necrosis if temperatures exceed 47 °C for over a minute. Factors influencing heat include drill size, speed, pressure, irrigation, and tool wear. Frequent drill replacement is essential, as wear from repeated use and sterilization affects performance. This study compared three pilot drills with similar designs from different manufacturers, testing each on pig ribs for 15 perforations after 15 sterilization cycles. Researchers measured temperature increase, drilling time, and surface wear. Results showed that drill no. 1 generated more heat than drills no. 2 and no. 3, though none reached critical temperatures. Drill no. 2 took the longest to reach the desired depth and displayed the most deformation. Findings highlight the importance of adhering to the recommended operational limits, suggesting that drills should be replaced after 15 cycles to ensure efficacy and patient safety.

Histomorphometric Analysis of Osseointegrated Intraosseous Dental Implants Using Undecalcified Specimens: A Scoping Review

Bone histology and histomorphometry are reliable diagnostic tools for the assessment of the bone-implant interface, material safety and biocompatibility, and tissue response. They allow for the qualitative and quantitative analysis of undecalcified bone specimens. This scoping review aims to identify the most common staining techniques, study models for in vivo experiments, and histomorphometric parameters used for quantitative bone evaluation of osseointegrated dental implants in the last decade. The Web of Science, PubMed, and Scopus databases were searched on 1 July 2024 for relevant articles in English, published in the last ten years, and the data were exported to an MS Excel spreadsheet. A total of 115 studies met the eligibility criteria and were included in the present review. The results indicate that the most common study models are dogs, rabbits, and pigs. Some of the most frequently used methods for the assessment of the bone-implant interface are the Toluidine blue, Stevenel's blue with Van Gieson, and Levai-Laczko stainings. The results from this study demonstrate that the most commonly used histomorphometric parameters in implant dentistry are the bone-to-implant contact (BIC), bone area fraction occupancy (BAFO), bone area (BA), and bone density (BD). This review presents the recent trends in histomorphometric analysis of dental implants and identifies some research gaps that necessitate further research.

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

STUDY DESIGN

A randomized, controlled, single-blind clinical trial.

OBJECTIVE

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSION

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

A Comparison of Different Implant Site Preparation Techniques in Low-Density Bone: An Ex-Vivo Study

INTRODUCTION

Osseointegration is considered a prerequisite for the long-term success of dental implants, and many researchers have considered the stability of the implant when placed in the bone. Many techniques include undersized drilling, densifying burs, magnetic mallets, and expanders. These methods have led to higher initial insertion torque values. The present study aims to evaluate the effectiveness of expanders, densifying burs, and magnetic mallet methods for preparing the implant site in low-density bone and compare them in terms of achieving good initial implant stability.

MATERIALS AND METHODS

The present study was conducted in an ex vivo animal model using bovine rib bones. This study was performed on 20 bovine ribs; each rib had four implant site preparations divided into four groups according to the drilling method: a control group of the conventional technique (n=20), the expanders group (n=20), the densification burs group (n=20), and the magnetic mallet group (n=20). The measured values were Primary Insertion Torque and Implant Stability Quotient (ISQ).

RESULTS

The highest average insertion torque was in the magnetic Mallet group, where the average was 43.75 N/cm2, followed by the burs group, where the average was 43.00 N/cm2, then the expanders group with an average of 32.80 N/cm2, then the conventional preparation group with 19.30 N/cm2 as the lowest average among the study groups. The highest ISQ mean was in the burs group, where the mean was 80.30, followed by the magnetic Mallet group, where the mean was 80.20, then the expanders group with a mean of 68.90, then the conventional preparation group with 50.10 as the lowest mean among the study groups.

CONCLUSION

Within the limitation of this study, we conclude that all methods used were better than conventional preparation in both ISQ and insertion torque, with the magnetic mallet group outperforming the insertion torque and the Densah burs outperforming the ISQ.

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

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

Emerging factors affecting peri-implant bone metabolism

Implant dentistry has evolved to the point that standard implant osseointegration is predictable. This is attributed in part to the advancements in material sciences that have led toward improvements in implant surface technology and characteristics. Nonetheless, there remain several cases where implant therapy fails (specifically at early time points), most commonly attributed to factors affecting bone metabolism. Among these patients, smokers are known to have impaired bone metabolism and thus be subject to higher risks of early implant failure and/or late complications related to the stability of the peri-implant bone and mucosal tissues. Notably, however, emerging data have unveiled other critical factors affecting osseointegration, namely, those related to the metabolism of bone tissues. The aim of this review is to shed light on the effects of implant-related factors, like implant surface or titanium particle release; surgical-related factors, like osseodensification or implanted biomaterials; various drugs, like selective serotonin reuptake inhibitors, proton pump inhibitors, anti-hypertensives, nonsteroidal anti-inflammatory medication, and statins, and host-related factors, like smoking, diet, and metabolic syndrome on bone metabolism, and aseptic peri-implant bone loss. Despite the infectious nature of peri-implant biological complications, these factors must be surveyed for the effective prevention and management of peri-implantitis.

A novel technique to harvest bone autografts with mild local hyperthermia and enhanced osteogenic bone quality: a preclinical study in dogs

BACKGROUND

Guided bone regeneration (GBR) involves collecting bone autografts with high bio-quality and efficiency. The current non-irrigated low-speed drilling has been limited for broader application in bone autograft harvest due to its low efficiency, inability to conduct buccal cortical perforation, and dependence on simultaneous implant placement. Increasing the drilling speed helps improve the efficiency but may incur thermal-mechanical bone damage. Most studies have addressed thermal reactions during bone drilling on non-vital models, which is irrelevant to clinical scenarios. Little has been known about bone's in vivo thermal profiles under non-irrigated higher-speed drilling and its influences on the resulting bone chips.

AIM

A novel technique for bone harvest and cortical perforation via in-situ non-irrigated higher-speed drilling was proposed and investigated for the first time.

METHODS

The third mandible premolars of eight beagles were extracted and healed for three months. Sixteen partial edentulous sites (left and right) were randomized into four groups for bone autograft harvest without irrigation: chisel, 50 rpm drilling, 500 rpm drilling, and 1000 rpm drilling. Bone chips were harvested on the buccal plates of the missing tooth. An infrared camera and an implantable thermocouple collaboratively monitored in vivo real-time bone temperature at the drilling sites. In vitro performances of cells from bone chips, including cell number, viability, proliferation, migration, ALP activity, in vitro mineralization, mRNA transcriptional level of osteogenic genes and heat shock protein 70 (HSP-70), and HSP-70 expression at the protein level were also studied.

RESULTS

500 rpm produced mild local hyperthermia with a 2-6 °C temperature rise both on the cortical surface and inside the cortical bone. It also held comparable or enhanced cell performances such as cell number, viability, proliferation, migration, ALP activity, in vitro mineralization, and osteogenic genes expression.

CONCLUSIONS

In-situ non-irrigated higher-speed drilling at 500 rpm using a screw drill is versatile, efficient, and thermal friendly and improves the bio-quality of bone chips. Our novel technique holds clinical translational potential in GBR application.

Heat Accumulation in Implant Inter-Osteotomy Areas-An Experimental In Vitro Study

To examine the influence of the distance between adjacent implant osteotomies on heat accumulation in the inter-osteotomy area, two experimental groups with 15 pairs of osteotomies in Type II polyurethane blocks were compared: 7 mm inter-osteotomy separations (Group A, n = 15) and 14 mm inter-osteotomy separations (Group B, n = 15). An infrared thermographic analysis of thermal changes in the inter-osteotomy area was completed. A one-way analysis of variance (ANOVA) and Fisher post-test were used to determine group differences. Higher temperatures were recorded in Group A at the coronal and middle levels compared to the apical level in both groups. The temperature reached max temperatures at T80s and T100s. In Group A, the threshold for thermal necrosis was exceeded. Meanwhile, Group B did not reach the threshold for thermal necrosis. Preparing adjacent implant osteotomies in dense bone with a 7 mm separation between their centers increases the temperature in the inter-osteotomy area, exceeding the threshold for bone thermal necrosis; meanwhile, increasing the distance between osteotomies reduces the thermal accumulation and the risk for thermal necrosis.

Simulated and clinical aerosol spread in common periodontal aerosol-generating procedures

Objectives

This study evaluated particle spread associated with various common periodontal aerosol-generating procedures (AGPs) in simulated and clinical settings.

Materials and methods

A simulation study visualized the aerosols, droplets, and splatter spread with and without high-volume suction (HVS, 325 L/min) during common dental AGPs, namely ultrasonic scaling, air flow prophylaxis, and implant drilling after fluorescein dye was added to the water irrigant as a tracer. Each procedure was repeated 10 times. A complementary clinical study measured the spread of contaminated particles within the dental operatory and quantified airborne protein dispersion following 10 min of ultrasonic supragingival scaling of 19 participants during routine periodontal treatment.

Results

The simulation study data showed that air flow produced the highest amount of splatters and the ultrasonic scaler generated the most aerosol and droplet particles at 1.2 m away from the source. The use of HVS effectively reduced 37.5–96% of splatter generation for all three dental AGPs, as well as 82–93% of aerosol and droplet particles at 1.2 m for the ultrasonic scaler and air polisher. In the clinical study, higher protein levels above background levels following ultrasonic supragingival scaling were detected in fewer than 20% of patients, indicating minimal particle spread.

Conclusions

While three common periodontal AGPs produce aerosols and droplet particles up to at least 1.2 m from the source, the use of HVS is of significant benefit. Routine ultrasonic supragingival scaling produced few detectable traces of salivary protein at various sites throughout the 10-min dental operatory.

Clinical relevance

The likelihood of aerosol spread to distant sites during common periodontal AGPs is greatly reduced by high-volume suction. Clinically, limited evidence of protein contaminants was found following routine ultrasonic scaling, suggesting that the the majority of the contamination consisits of the irrigant rather than organic matter from the oral cavity.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00784-022-04532-8.

Application of reverse drilling technique in alveolar ridge expansion

Background/purpose

Recently, there is a new model adjustment in the osteotomy preparation named osseodensification. This study focused on the ridge expansion results based on reversed drilling technique regarding osseodensification technique and the modified method.

Materials and methods

Twenty-seven samples were fabricated from sawbones, tailored into three different widths: 6.75 mm, 7.25 mm, and 7.75 mm, and drilled by three different protocols: osseodensification bur with 1500 rpm reverse torque, triple-bladed drill with 200 rpm reverse torque, and triple-bladed drill with 1600 rpm standard forward turning; each group contained three samples. After implants were screwed into the sawbones over 5mm or till the bone fractured, the width change of the bone was measured, the insertion depth of the implant was calculated, and the fracture of the bone was also recorded for comparison.

Results

The result showed that in narrow bone width (6.75 mm) the enlargement of bone thickness showed significant difference among the groups (P < 0.05); both reverse torque group expressed a higher expansion result, but in the paired comparison, only osseodensification bur expanded the ridge significantly better than the standard drilling sequence. However, implant insertion depth of osseodensification group was significantly less than those of other two drilling protocols (P < 0.005). Even though the bone fracture happened least in the standard drilling sequence, there is no difference among the groups.

Conclusion

The counter-clockwise rotating method possesses the ability to expand bone ridge but lead to a higher stress in the bone structure, which may affect the insertion depth of the implants.