The exposing of dental implant into the maxillary sinus combined with membrane perforation might increase risks of implant failure and sinus complications. The purpose of this study was to investigate the effects of the dental implant penetration into the maxillary sinus cavity in different depths on osseointegration and sinus health in a dog model.
Sixteen titanium implants were placed in the bilateral maxillary molar areas of eight adult mongrel dogs, which were randomly divided into four groups according to the different penetrating extents of implants into the sinus cavities group A: The block biopsies were harvested five months after surgery and evaluated by radiographic observation and histological analysis.
No signs of inflammatory reactions were observed in any maxillary sinus of the eight dogs. The tips of the implants with penetrating depth of 1 mm and 2 mm were found to be fully covered with newly formed membrane and partially with new bone. The tips of the implants with penetrating depth over 3 mm were exposed in the sinus cavity and showed no membrane or bone coverage.
No significant differences were found among groups regarding implant stability, bone-to-implant contact BIC and bone area in the implant threads BA. Despite the protrusion extents, penetration of dental implant into the maxillary sinus with membrane perforation does not compromise the sinus health and the implant osseointegration in canine. While a limited amount of bone is generally present at the edentulous posterior maxilla due to atrophy of alveolar ridge and pneumatization of the maxillary sinus, several techniques have been described in which dental implants are inserted marginally to the bony sinus floor with a localized augmentation procedure 3 Since these approaches have become conventional treatments in Implant Dentistry, the risk of exposing the implant to the maxillary sinus increased.
In general, the sinus membrane perforation is considered as a potential risk factor for implant failure and sinus infection. Some investigators claimed that the membrane perforation was strongly associated with the occurrence of postoperative sinus infection 622while others assumed that there was a correlation between implant failure and sinus membrane perforation 811 However, clinicians have generally reported that slight membrane perforation after implant placement does not play a significant role in the clinical outcome 415 Nevertheless, the available literature has not conclusively determined so far the significance of implant exposure to the sinus cavity on implant survival and maxillary sinus complication, particularly with respect to the histological evidences.
Because most reported results of the sinus membrane perforation are clinical observations, they lack well-defined outcome criteria or control. In order to help clinicians to make proper surgical decisions, data on a more controlled scientific level is necessary to be provided. The purpose of the present study was to evaluate the effects of dental implant exposure to maxillary sinus cavity with penetrating depth of mm on osseointegration and sinus health in a dog model after a 5-months healing period.
Eight healthy adult male mongrel dogs weight The animals were housed individually in indoor cages and the diet during the course of the experiment was whole grain flour, cornmeal, soybean cake, fishbone meal, and eggs, according to the general feeding program Hole n one floor penetration covers Experimental Animal Center of Dalian Medical University, China.
The protocol for this animal study was approved by the Ethics Committee of Dalian Medical University protocol number: A split-mouth randomized design, using four treatment protocols on the Hole n one floor penetration covers of bilateral maxillary first molars, was employed. In total, 16 samples were used in this study. Each implant recipient site was randomly assigned to one of the four treatment protocols, and immediate implant placement was applied accordingly: The investigators ensured unpredictability of the allocation sequence by coin toss before surgeries.
Ltd, Zhengzhou, China to prevent infection. The whole surgical procedure was performed under sterile conditions by only one surgeon W. After the maxillary first molars were extracted bilaterally with special care, immediate implant placements were performed in the palatal sockets.
After the bone and mucous membrane of the sinus floors were intentionally drilled through, the level of the sinus floor was detected with a dental probe and the height of residual ridge was measured. Except for the implants of control group placed within the alveolar bone without protruding into the sinus cavity, the other twelve implants were placed bilaterally in the sinus in such a way that they penetrated the bone and mucous membrane of the maxillary sinus floor to the extent of 1 mm, 2 mm, or 3 mm, respectively.
The buccal mucoperiosteal flaps were released and sutured with vicryl resorbable sutures. A soft diet was given to the animals during the healing period. Five Hole n one floor penetration covers after surgery, the animals were sacrificed with overdose pentobarbital sodium and vascular perfusion was undertaken with paraformaldehyde.
The sample blocks of maxilla with implants were harvested and the upper walls of the sinus were eliminated to expose the sinus floor. After a gross observation, Hole n one floor penetration covers examination was performed with periapical radiograph using paralleling technique, and the X-ray beam was perpendicular to the long axis of the implant and film. All samples were shot using the following exposure conditions: Thereafter, the membrane adjacent to the implant was processed into paraffin section and stained with hematoxylin and eosin.