Osseodensification in Implant Dentistry for Ridge Expansion and Transcrestal Maxillary Sinus Augmentation: Case Report

Osseodensification has been a subject of interest in the research arena. It employs
densah bur, with negative rake angle and counterclockwise motion, to perform nonsubtractive
drilling. In the presence of copious irrigation, it can push the bone trabeculae
into the osteotomy instead of leaving it. This compaction can increase bone density, bone
volume and subsequently enhance implant stability. The aim of this study is to report a
case using densah bur successfully for osseous densification and crestal maxillary sinus
augmentation. Further clinical trials are required to validate these findings and confirm
whether it can be used for ridge expansion.


Introduction
Sufficient amount of pristine bone surrounding dental implants is perquisite for successful osseointegration. Unfortunately, maxillary sinus pneumatization and posterior alveolar ridge atrophy occur rapidly following extraction of maxillary posterior teeth. Attempts have been made to increase primary mechanical and secondary biologic stability via improving bone quality and quantity. Bone expanders have been used to increase bone width, but at the expense of causing trabecular microfractures with subsequent bone resorption [1]. Techniques to improve bone height in the posterior maxilla have been introduced including maxillary sinus lift whether direct (lateral window) or indirect (crestal) approach. The direct approach is invasive with greater possibility of patient morbidity in contrast to the crestal approach.
However, the latter technique poses a 24% risk of sinus membrane perforation due to impaired visibility [2].
Another technique, adopting the concept of osseodensification, was introduced in 2014 and seems to be promising solution to the limitations of the techniques of enhancing bone quantity and quality.
It is based on a special bur with counterclockwise drilling, called Densah bur (Versah, USA). Non-subtractive reverse drilling, using copious amounts of irrigation, can push the cut bony trabeculae into the osteotomy instead of leaving it. This compression increases bone width two to three folds and increases bone density compared to regular drilling [3]. Elsayyad and Osman concluded that despite being very promising, the studies favoring osseodensification are mainly animal studies with high risk of bias [4]. This calls for the need for conducting human studies of higher evidence. Therefore, the aim of this study is to report a case employing osseodensification to enhance bone quality and quantity in atrophic posterior maxillary ridge. Ridge expansion along with crestal sinus lift using densah bur was accompanied with simultaneous implant placement.

Case Representation
A 40-year-old female patient was referred to the Prosthodontics department in our School of Dentistry in January 2018. The patient's informed consent was obtained to include her photographs and radiographs in our study. Intra-oral examination of the maxillary arch ( Figure 1) revealed multiple carious lesions which were restored with composite resin. Remaining roots of maxillary left premolars and first molar as well as non-restorable maxillary left second molar, due to extensive subgingival caries, were extracted. Implants insertion was delayed for 6 months after extraction to allow for complete remodeling of the extraction sockets. CBCT requested two weeks prior to implants' placement showed slightly deficient bone bucco-lingually in the maxillary left first premolar region ( Figure 2A). Furthermore, diminished bone height (4.19 mm) was evident in the left second molar region ( Figure 2B).
Hence, densah bur was used for ridge expansion and crestal sinus lift in the left first premolar and second molar respectively.  CBCT showing slightly deficient bone width for implant in the first premolar region, b.
CBCT showing maxillary sinus pneumatization and reduced bone height for implant in the second molar region, c.
Peri-apical x-rays were taken prior to implant surgery for comparative purposes ( Figure 2C). In the first premolar region, drilling using Densah burs (VS8) proceeded under counterclockwise pumping motion ( Figure 3A). During insertion of the final drill (3.5×11.5 mm), fenestration of the buccal wall of the osteotomy occurred. Implant (4×11.5 mm) (Neobiotech, Korea) was inserted and the dehiscence was managed by grafting with DM Bone (Neobiotech, Korea) and T-Gen membrane (SK bioland Co., Korea) ( Figure 3B). In the second molar region, pilot drill was inserted 1 mm short of the sinus membrane. Particulate DM Bone was packed into the prepared osteotomy. Sequential drilling then proceeded employing 200 rpm speed without irrigation, so that the densah bur can push the grafts coronally ( Figure 4A & 4B).
The patient was followed-up for a period of six months with no complications. Buccal wall fenestration occurred which was managed using particulate bone graft and membrane. Densah bur compressing the bone graft into the osteotomy for crestal sinus lift, b.
Sequential drilling produced densification of the sinus floor (blue arrow) with the compressed bone graft (yellow arrow) elevating the sinus membrane, c. Implant (4×7.3 mm) inserted into prepared osteotomy.