SINGLE VS SEQUENTIAL DRILLING IN IMPLANTOLOGY: A SYSTEMATIC REVIEW

screening n: 27 +RCT found by hand searching (n:2) Publications finally included (n=9) Publications obtained (n=22) Publications excluded after full text


ISSN: 2320-5407
Int. J. Adv. Res. 8(04), 251-258 252 the bone tissue and the implant without the presence of fibers, is the key of success of this type of treatment. The successful osseointegration of a dental implant depends on achieving a good primary stabilization to bone. The preservation of bone cell vitality is a crucial condition for its healing and maturation process, and for setting-up a stable bone-to-implant contact. However, bone cell vitality depends on the quantity of surgical trauma and the damage caused by the thermal rising.
The insertion of dental implants normally engages prior drilling procedures for making implant site. Conventionally, this drilling is done in a sequential way using gradual sizes of drills. However, sequential drilling may be timewasting and disagreeable for the patient (long intervention). Moreover, extendedtime of tissue exposure may be damagingthe healing responseand prolonging the exposure to the oral environment, which may produce infection. Nowadays, the clinical advances tend to simpler and minimally invasive procedures. In that respect, simplified drilling was proposed, which consists of minimizing the number of drills through the use of a pilot drill followed by a unique final drill or directly by using a single drill.
Our work means through a literature review, to identify the best implant placement procedure, by a single drilling or a gradual drilling method, and which one leads to a better cicatrization process.

Materials and Method:-Systematic Search Strategy:
Before the beginning of the systematic literature search, the protocol was agreed by the authors. An electronic search was performed through MEDLINE database (PubMed) (https://www.ncbi.nlm.nih.gov/pubmed).We meant to include only articles published in English during the last 10 years from "03/01/2009" to "03/01/2019". The following combination of MeSH terms was used in PubMed: "single drilling AND dental implant". Then a hand search was performed in Ebsco database. Two independent reviewers achieved the quality assessment of the articles retained and two other authors achieved screening, data abstraction and writing of the review. The data collected was categorized and was organized according to the "PICO" approach as seen in the table below.

Discussion:-
The results of our review revealed that there is large heterogeneity of methods of testing, protocols and also the materials tested (human bone, rabbit bone, bovine bone, Synthetic block, osseous study model) which make the comparison of the studies difficult.
It is known that the actual tendency in the dental field is to shorten the treatment duration and decrease the treatment costs. Single drilling allows to simplify the procedure of implant placement.
It has beenshown to be a reliable method with no significant differences regarding the bone healing, complications, and patient's satisfaction, when compared to the conventional implant placement.
According to the study of Gehrke S.A and al 2018, the use of a single bur system achieves greater precision in the osteotomy than a conventional drilling sequence while preparing implant site and can be considered as safe as the latter. It may increase the torque of insertion and consequently the initial stability of the implants. Conversely, Mohlhenrich SC and al 2016, established that the single drilling procedure could generate more heat than traditional sequential drilling during implant bed preparation in artificial bone types I and II. Therefore, bone density and drill diameter influence thermal increases. Particularly in poorer density bone, conventional drilling seems to raise the temperature less. Nevertheless, since the study was conducted in a synthetic bone material, it is not identified if the results can be applied to humans.
Mohlhenrich SC and al 2016 also stated that bone density influences temperature development during implant bed preparation. In agreement with the results of Gehrkeand al. 2015, no differences in heat generation were found between the two surgical protocols using each drill diameter in type II bone. However, it was found that with decreasing density, higher temperatures could be expected using the single drilling. Thus, it was found that in lowdensity synthetic bone, sequential implant site preparation generates less temperature, and in high-density bone, single drilling, especially small-diameter osteotomy, generates less temperature.
It is still crucial to emphasize on some precautions like the speed of drilling. Moreover, slow drilling speeds required significantly more time to finish the preparation of the implant bed shown as follows: 50 rpm > 150 rpm > 300 rpm > control (1200 rpm) (p < 0.05). According to that study, also the diameter and design of drills are significantly important. In fact, it has been shown that using a single-bur protocol with tapered and multistepped twist drills of 3.2 or 3.6mm, with a slow drilling speed of 300 rpm in type IV bone density seems to be more efficient in terms of temperature increase and time reduction.
According to the RCT of Guazzi and al in 2015, both drilling techniques produced successful results over a 4-month post-loading follow-up period, but the single bur procedure required less surgical time and lead to less postoperative morbidity which seems interesting regarding to patient satisfaction and comfort. This team emphasized also on the importance of using sharp drills with high rotation speed(1,500 rpm ) in combination with a large applied force and a good irrigation mode, this allows a faster site preparation and a minimum increase of temperature in comparison to lower rotation speed and pressure. Conversely, the use of worn burs makes it difficult to create a breach into the bone, with a consequent prolonged tissue exposure to heat, which, in turn, increases the risk of bone necrosis.
Marheineke and al raised the concerns on the impossibility of adjusting the axis of implant site if using a single bur method, while that Multi-step drilling technique carries the option of detecting and adjusting the axis of misaligned implant sites in early stages. Which needs a steeper learning curve, even for experienced surgeons, and encourages the combination of surgical guidance and single-drill technique allowing a precise implant placement and minimizing the operative discomfort for the patient. Additionally, Gehrke S.A and al 2018 investigated the bone behavior and the osseointegration of both systems and showed that a single drill system did not change the biomechanical and/or biological of peri-implant tissue response more than a conventional drilling sequence does, while preparing implant site, and indicated that this approach is as safe as the sequential one, and may also increase the torque of insertion and consequently the initial stability of the implants.