30 July 2019

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Exposing dental implants into the sinus cavity: complications and survival

Lara Figini

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The edentulous posterior maxillary region often presents with unique challenging conditions in implant dentistry. Limited bone height secondary to pneumatization of the maxillary sinus and the resorption of the alveolar ridge preclude in many instances the installation of dental implants. To compensate for the lack of bone height, several treatment options have been proposed, including the placement of short implants (a technique that is certainly more conservative and minimally invasive), the use of bone grafts or fillers, the  sinus augmentation technique with or without regenerative. The maxillary sinus is a para-nasal pyramid-shaped cavity covered by the Schneiderian membrane. The integrity of the membrane is important for the execution of breast augmentation procedures and to avoid potential complications. However, membrane perforation is the most common complications and occurs approximately in 15.7% of cases. Some literature studies have even suggested that these perforations do not have a l negative impact on implant survival or on the future complications.  

MATERIALS AND METHODS
In a systematic review published on the International Journal of Implant Dentistry, the authors investigated the relevance of implant intrusion into the maxillary sinus (without regenerative techniques) on implant survival and possible related complications. A search of the electronic and world manual literature was performed by two independent reviewers  using various databases, including MEDLINE, EMBASE and Cochrane Oral Health Group Trials Register, for articles up to January 2018 reporting outcome of implant placement perforating the sinus floor without regenerative procedure (lateral sinus lift or transalveolar technique) and graft material. The intrusion of the implants can occur during drilling or implant placement, with and without punch out Schneiderian. Only studies with at least 6 months of follow-up were included in the qualitative assessment.

RESULTS
Eight studies provided information on the survival rate, with a total sample of 493 implants, and with a weighted survival rate of 95.6% (95% CI), after 52.7 months of follow-up. The penetration level of the implant (≤4mm or >4mm) did not report statistically significant differences in the survival rate (p = 0.403). Seven studies provided information on the rate of clinical complications, with an average complication rate of 3.4% (95% CI). The most frequent clinical complication was epistaxis, without finding significant differences according to the level of penetration. Five studies provide information on the radiographic complication; the most common complication was thickening of the Schneiderian membrane.     

CONCLUSIONS
From the data emerging from this systematic review, which must be confirmed by results of similar revisions, it can be concluded that the overall survival rate of implants with an emergency in the maxillary sinus is 95.6%, without statistical differences based on the level of penetration. Clinical and radiological complications are 3.4% and 14.8%, respectively. The most frequent clinical complication is epistaxis, and the radiological complication is the thickening of the Schneiderian membrane, without statistically significant difference based on the level of penetration of  implant inside the sinus.     

CLINICAL IMPLICATIONS
Several limitations could be described for the present review. Firstly, there is a lack of a control group in the included studies, to compare outcomes and complications, with implant placed in native bone, or with regenerative techniques. Second limitation was related to the types of included studies being seven retrospectives  and one prospective study. Third, the lack of a reliable method to evaluate the millimeters of implants intruded inside the maxillary sinus and to assess sinus membrane perforation or not. Fourth, the analysis of the radiographic complications has been analyzed only in three studies with computerized tomography and in two studies by orthopantomographies and periapical radiographs.

(Photo credit: Dr. Danilo Alessio Di Stefano)

For additional informations: 
Influence of exposing dental implants into the sinus cavity on survival and complications rate: a systematic review

Italian version: http://www.odontoiatria33.it/implantologia/17549/intrusione-di-impianti-nel-seno-mascellare-complicanze-e-sopravvivenza.html