Maxillary sinus augmentation using
autogenous tooth bone graft
Objectives: To investigate the effectiveness of the freshly extracted dental particulate in maxillary sinus grafting.
Patients and Methods: This prospective study was carried on 12 patients who underwent sinus augmentation and received 20 implants after 6 months from the sinus lift procedure. After atraumatic extraction, the teeth were ground and processed into a bacteria free particulate and then grafted immediately into the maxillary sinus. The quantity of bone formation, level of the sinus floor and implant survival rate were evaluated.
Results: x-ray and biopsy of grafting sites showed a dense dentin-bone composite, while histomorphometric analysis demonstrated that the tooth bone graft has a very good results of gradual resorption accompanied with new bone formation.
Conclusions: Autogenous tooth particulate grafted immediately after extractions is safe and successful biomaterial with excellent bone forming capacity in sinus augmentation, it can be considered as a good alternative to bone graft in sinus lift procedure.
Keywords: Tooth bone graft, demineralized dentin particulate, maxillary sinus augmentation.
* Lecturer of Oral and Maxillofacial Surgery, Faculty of Oral and Dental Medicine, Cairo University.
Bone grafts have been effectively used to reconstruct bony defects; they help the alveolar bone in restoring its original structure, appearance and function. There are four types of bone graft materials: autograft, allograft, xenograft and alloplast, the utilization of these materials relies upon clinical applications, volume of deficiency and evidence based investigations (1). Autograft has been considered the gold standard, due to its regenerative osteogenicity, osteoinductivity and osteoconductivity (2). However, many clinicians do not favor autograft due to donor site complications, prolonged surgical time and limited grafts amount (3). Therefore many researchers, in a trial to compensate the disadvantages of autografts, focused on human tooth as one of the intraoral donor sites with great chemical similarities to bone (4).
Teeth and bones share numerous similarities; Teeth, nerves, cartilages and maxillofacial bones all embryologically originated in the neural crest, also both have similar chemical compositions; the dentin of the teeth and the bone have 65% inorganic parts including the calcium phosphate lineage and 35% organic components such as collagen, it is therefore not surprising that dentin that involves more than 85% of tooth structure can serve as native bone grafting material (5).
Tooth extraction is one of the most widely performed procedures in dentistry with a lot and well documented reports of causing significant dimensional changes of the alveolar ridge (4). Currently, all extracted teeth are viewed as a clinical waste and in this manner are simply discarded. Recently, several investigations revealed that extracted teeth from patients that undergo a process of cleaning, crushing, demineralization and sterilization is a perfect grafting material in filling bone defects (6).
After tooth loss, maxillary sinus pneumatization and alveolar bone resorption usually occurs leading to atrophied maxilla not suitable for implant placement. Sinus lift procedure is designed to provide bone to atrophied maxilla. It increases the available bone volume via guided bone regeneration using the sinus membrane as a natural barrier (7). Sinus lift was initially introduced by Tatum in 1976, while the first publication describing this procedure was by Boyne and James in 1980 (8-9).
The lateral sinus augmentation technique is usually recommended when the remaining alveolar bone height is less than 4-5 mm, it provides greater membrane elevation and consequently more gain in postoperative bone volume compared to the minimally invasive crestal approach technique(10).
The purpose of this study is to evaluate the effectiveness of the autogenous tooth bone graft materials as a near-gold standard graft with low technique sensi¬tivity in maxillary sinus augmentation.
Patients and methods:
This study was carried in accordance with international standards of quality for clinical trials, the Declaration of Helsinki; 12 patients were selected from the outpatient clinic of the Department of Oral and Maxillofacial Surgery, Faculty of Oral and Dental Medicine, Cairo University. All the patients underwent maxillary sinus augmentation procedure utilizing autogenous tooth bone graft materials while 20 delayed implant placement was performed after six months from the augmentation procedure in the second surgery. All the patients received information about the surgical procedures and gave written informed consent.
A preoperative cone-beam computed tomographic (CBCT) scan is taken for inspection of the sinus and for measuring the remaining residual ridge till the sinus floor, the selected patients have thickness of bone less than 3mm, making them candidates for 2 stage surgical procedures; the first is open sinus lift and the second is for implant placement after 6 months. Presence of at least one vital non restorable tooth indicated for extraction in the included patient is mandatatory to be utilized as the graft material. Exclusion criteria included: patients who are not candidates for the sinus augmentation and implant surgeries (poor oral hygiene – aggressive periodontitis – bruxism – systemic disease affecting healing process and heavy smokers) ‘Light smokers were committed to a smoking cessation protocol before the surgeries’.
Surgery and tooth Bone Materials
Atraumatic extraction was done to the non restorable tooth or teeth, they were free of any root canal fillings, and the cause of extraction was mainly advanced and progressive periodontal bone loss or other reasons, such as orthodontic indications, severe caries or wisdom teeth removal. Immediately after extraction, restorations like fillings and crowns, calculus, carious lesions, and remaining periodontal ligament were removed. The roots are splitted in case of multi-roots; teeth were cleaned and dried via air syringe, then were grinded by bone mill into small dentin particles (Fig.1).
Fig. 1: (A): extracted roots after cleaning (B): dentin particulate after grinding
The dentin particles is immersed in basic alcohol cleanser for 10 minutes to dissolve all organic debris and bacteria, demineralized with a 2% acid formic solution to transform to demineralized dentin particulate (DDM) then, the particulate is washed by sterile phosphate-buffered saline. The bacteria-free dentin particulate is ready for grafting the maxillary sinus. The procedure from tooth extraction until grafting takes approximately 20 minutes.
Caldwell-Luc procedure was done under local anesthesia; crestal incision on the edentulous ridge.with a mesiovertical release was made followed by elevation a full-thickness mucoperiosteal flap.to expose both the alveolar ridge and lateral maxillary wall. A bony window into.the sinus was made using carbide round.bur. After gently detaching from the lateral.wall and floor, the Schneiderian membrane was.elevated upward for tooth bone graft placement. DDM was placed into the prepared site with no use of membrane except if perforation is suspected (Fig.2).The flap is closed with minimal tension and the patient was given sinus precautions instructions and antibiotics, also patient was advised to spray the nostrils with a decongestant aerosol.
Fig. 2: (A): elevation of the Shneiderian membrane (B): dentin particulate filling sinus
Second-stage surgery was performed after 6 months, it included dental implant placement and biopsy harvesting; a 2mm diameter trephine bur was utilized to collect the tooth bone graft biopsy from the grafted sinuses, where the drilling depth was planned from the CBCT.
Postoperative CBCT radiographs were taken for every patient one week, 6 months and 12 months after the first surgery. In order to standardize the radiographic evaluation, the radiographs were performed by the same clinician and with the same device (Scanora1; Soredex Orion Corporation Ltd., Helsinki, Finland) using the same settings and the same software program. Radiographic evaluation was focused on bone quantity measuring the highest point of new sinus floor with a millimeter scale by the software (Fig. 3).
A B C D
Fig. 3: (A): Preoperative CBCT before tooth removal showing 2 mm of bone present in maxillary molar furcation.
(B): CBCT 1 weak after augmentation with 13 mm of ridge height.
(C): CBCT at the 6 months follow up showing 11.5 mm of ridge height.
(D): CBCT at the 12 months follow up showing implant placement within the grafted sinus
Core biopsy was fixed by 10% buffered formalin. When submitted for histologic examination, decalcification of the specimen was attained by suspension in EDTA 10% solution for fourteen days with regular rechanging of the solution every day. Dehydration of the specimen was then achieved using alcohol, followed by clearing in xylol. Afterward it was inserted in paraffin wax to be in a block form. The paraffin block was segmented longitudinally using a microtome into thin paraffin sections, each of approximately 5 microns thick. The sections were stained with Hematoxylin and Eosin. Stained sections were examined in order to estimate the newly formed bone in the graft (Fig. 4).
Fig. 4: A histology section of core biopsy with the arrow denoting newly formed bone matrix beside dentinal tubules
Statistical analysis was performed using SPSS 12.0 (Statistical package for the social sciences- IBM Corp., Armonk, NY). The data were represented as mean ± standard deviation, The Student’s t test was used to analyze for changes in bone height with time. The level of significance was set to