A novel, new generation drill coating for osteotomy site preparation

Background: Implant success and survival rate ranges from 93% to 97%; however, failures are not very uncommon. These failures can be caused due to a variety of reasons out of which increased heat during drilling of osteotomies is a major contributor.Aim: The aim of this study was to develop a new generation diamond-coated drill and compare the thermal changes between commercially available drills and the experimental diamond coated drill during implant site preparation in artificial bone. Material and Methods: Three types of drills were selected for the study; Group A (Carbide), Group B (Stainless Steel), and Group C (Experimental). A total of 60 implant site preparations were performed with all the drills in artificial bone using a surgical unit linked to a testing device, in order to standardize implant drilling procedures. Bone temperature variations were recorded when drilling at a depth of 10 mm. A constant irrigation of 50 ml/minute and drilling speed of 800 r.p.m. was maintained. Results: The mean temperature of Group A, Group B, and Group C was 35.57°C, 36.83°C and 34.23°C, respectively. The results were assessed and statistically analyzed using ANOVA test and post hoc Bonferroni test. Statistically significant higher temperatures were obtained with stainless steel drill and carbide drill when compared with the experimental diamond coated drill. (P = 0.000). Conclusions: Diamond coated osteotomy drills have shown promising results in reducing heat generation at the osteotomy. Further studies need to be conducted to maximize the potential use of diamond as components of drills in implant dentistry.

Evaluation of biogas and syngas as energy vectors for heat and power generation using lignocellulosic biomass as raw material

The use of nonrenewable energy sources to provide the worldwide energy needs has caused different problems such as global warming, water pollution, and smog production. In this sense, lignocellulosic biomass has been postulated as a renewable energy source able to produce energy carriers that can cover this energy demand. Biogas and syngas are two energy vectors that have been suggested to generate heat and power through their use in cogeneration systems. Therefore, the aim of this review is to develop a comparison between these energy vectors considering their main features based on literature reports. In addition, a techno-economic and energy assessment of the heat and power generation using these vectors as energy sources is performed. If lignocellulosic biomass is used as raw material, biogas is more commonly used for cogeneration purposes than syngas. However, syngas from biomass gasification has a great potential to be employed as a chemical platform in the production of value-added products. Moreover, the investment costs to generate heat and power from lignocellulosic materials using the anaerobic digestion technology are higher than those using the gasification technology. As a conclusion, it was evidenced that upgraded biogas has a higher potential to produce heat and power than syngas. Nevertheless, the implementation of both energy vectors into the energy market is important to cover the increasing worldwide energy demand.

Various bio-mechanical factors affecting heat generation during osteotomy preparation: A systematic review

As implant site preparation and bone are critical precursors to primary healing, thermal and mechanical damage to the bone must be minimized during the preparation of the implant site. Moreover, excessively traumatic surgery can adversely affect the maturation of bone tissue at the bone/implant interface and consequently diminish the predictability of osseointegration. So, this study was carried out to evaluate the various biological and mechanical factors responsible for heat generation during osteotomy site preparation to reduce the same for successful osseointegration of dental implants. Study Design: A broad search of the dental literature in PubMed added by manual search was performed for articles published between 1992 and December 2015. Various bio-mechanical factors related to dental implant osteotomy preparation such as dental implant drill designs/material/wear, drilling methods, type of irrigation, and bone quality were reviewed. Titles and abstracts were screened and articles which fulfilled the inclusion criteria were selected for a full-text reading. Results: The initial database search yielded 123 titles, of which 59 titles were discarded after reading the titles and abstracts, 30 articles were again excluded based on inclusion and exclusion criteria, and finally 34 articles were selected for data extraction. Many biological and mechanical factors responsible for heat generation were found. Conclusion: Literatures of this review study have indicated that there are various bio-mechanical reasons, which affect the temperature rise during osteotomy and suggest that the amount of heat generation is a multifactorial in nature and it should be minimized for better primary healing of the implant site.

Effect of different light curing units on Knoop hardness and temperature of resin composite.

Aim: To evaluate the influence of quartz tungsten halogen and plasma arc curing (PAC) lights on Knoop hardness and change in polymerization temperature of resin composite. Materials and Methods: Filtek Z250 and Esthet X composites were used in the shade A3. The temperature increase was registered with Type-k thermocouple connected to a digital thermometer (Iopetherm 46). A self-cured polymerized acrylic resin base was built in order to guide the thermocouple and to support the dentin disk of 1.0 mm thickness obtained from bovine tooth. On the acrylic resin base, elastomer mold of 2.0 mm was adapted. The temperature increase was measured after composite light curing. After 24 h, the specimens were submitted to Knoop hardness test (HMV-2000, Shimadzu, Tokyo, Japan). Data were submitted to ANOVA and Tukey's test (a = 0.05). Results: For both composites, there were no significant differences (P > 0.05) in the top surface hardness; however, PAC promoted statistically lower (P < 0.05) Knoop hardness number values in the bottom. The mean temperature increase showed no significant statistical differences (P > 0.05). Conclusion: The standardized radiant exposure showed no influence on the temperature increase of the composite, however, showed significant effect on hardness values.

A Study On The Temperature Changes Of Bone Tissues During Implant Site Preparation / 대한치과보철학회지

The purpose of this study is to examine the possibility of thermal injury to bone tissues during an implant site preparation under the same condition as a typical clinical practice of Branemark implant system.All the burs for Branemark implant system were studied except the round bur.The experiments involved 880 drilling cases:50 cases for each of the 5 steps of NP, 5 steps of RP,and 7 steps of WP,all including srew tap,and 30 cases of 2mm twist drill. For precision drilling,a precision handpiece restraining system was developed(Eungyong Machinery Co.,Korea).The system kept the drill parallel to the drilling path and allowed horizontal adjustment of the drill with as little as 1 mu m increment.The thermocouple insertion hole.that is 0.9mm in diameter and 8mm in depth,was prepared 0.2mm away from the tapping bur,the last drilling step.The temperatures due to countersink,pilot drill,and other drills were measured at the surface of the bone,at the depths of 4mm and 8mm respectively. Countersink drilling temperature was measured by attaching the tip of a thermocouple at the rim of the countersink.To assure temperature measurement at the desired depths,''bent-thermocouples'' with their tips of 4 and 8mm bent at 120 were used.The profiles of temperature variation were recorded continuously at one second interval using a thermometer with memory function (Fluke Co.,U.S.A.)and 0.7mm thermocouples (Omega Co.,U.S.A.). To simulate typical clinical conditions,35mm square samples of bovine scapular bone were utilized.The samples were approximately 20mm thick with the cortical thickness on the drilling side ranging from 1 to 2mm.A sample was placed in a container of saline solution so that its lower half is submerged into the solution and the upper half exposed to the room air,which averaged 24.9 degrees C.The temperature of the saline solution was maintained at 36.5 degrees C using an electric heater (J.O Tech Co.,Korea).This experimental condition was similar to that ofa patient's opened mouth. The study revealed that a 2mm twist drill required greatest attention.As a guide drill, a twist drill is required to bore through a '' virgin bone,''rather than merely enlarging an already drilled hole as is the case with other drills.This typically generates greater amount of heat.Furthermore,one tends to apply a greater pressure to overcome drilling difficulty, thus producing even greater amount heat. 150 experiments were conducted for 2mm twist drill.For 140 cases,drill pressure of 750g was sufficient,and 10 cases required additional 500 or 100g of drilling pressure.In case of the former,3 of the 140 cases produced the temperature greater than 47 degrees C,the threshold temperature of degeneration of bone tissue (1983.Eriksson et al.5))which is also the reference temperature in this study.In each of the 10 cases requiring extra pressure,the temperature exceeded the reference temperature.More significantly,a surge of heat was observed in each of these cases.This observations led to addtional 20 drilling experiments on dense bones.For 10 of these cases,the pressure of 1,250g was applied.For the other 10,1,750g were applied.In each of these cases,it was also observed that the temperature rose abruptly far above the thresh-old temperature of 47 degrees C,sometimes even to 70 or 80 degrees C.It was also observed that the increased drilling pressure influenced the shortening of drilling time more than the rise of drilling temperature.This suggests the desirability of clinically reconsidering application of extra pressures to prevent possible injury to bone tissues. An analysis of these two extra pressure groups of 1,250g and 1,750g revealed that the t-statistics for reduced amount of drilling time due to extra pressure and increased peak temperature due to the same were 10.80 and 2.08 respectively suggesting that drilling time was more influenced than temperature. All the subsequent drillings after the drilling with a 2mm twist drill did not produce excessive heat, i.e.the heat generation is at the same or below the body temperature level. Some of screw tap,pilot,and countersink showed negative correlation coefficients between the generated heat and the drilling time,indicating the more the drilling time,the lower the temperature. The study also revealed that the drilling time was increased as a function of frequency of the use of the drill.Under the drilling pressure of 750g, it was revealed that the drilling time for an old twist drill that has already drilled 40 times was 4.5 times longer than a new drill. The measurement was taken for the first 10 drilings of a new drill and 10 drillings of an old drill that has already been used for 40 drillings. ''Test Statistics''of small samples t-test was 3.49,confirming that the used twist drills require longer drilling time than new ones.On the other hand,it was revealed that there was no significant difference in drilling temperature between the new drill and the old twist drill. Finally,the following conclusions were reached from this study: 1.Used drilling bur causes almost no change in drilling temperature but increase in drilling time through 50 drillings under the manufacturer-recommended cooling conditions and the drilling pressure of 750g. 2.The heat that is generated through drilling mattered only in the case of 2mm twist drills,the first drill to be used in bone drilling process;for all the other drills there is no significant problem. 3.If the drilling pressure is increased when a 2mm twist drill reaches a dense bone, the temperature rises abruptly even under the manufacturer-recommended cooling conditions. 4.Drilling heat was the highest at the final moment of the drilling process.