Relevant anatomic and biomechanical studies for implant possibilities on the atrophic maxilla: critical appraisal and literature review.
OBJECTIVE
The purpose of this review was to highlight anatomic and biomechanical aspects of atrophic maxillae for implant possibilities.


METHODS
A MEDLINE electronic search of the years 1966 to 2009 was conducted with the keywords "atrophic,""resorbed,""edentulous," and "maxilla."


RESULTS
Twenty papers presented the following findings: (1) previous use of a removable prosthesis is a risk factor for resorption, with flabby tissues related to the severity of resorption; (2) implants in the reconstructed maxilla (< or =5 mm) and supporting overdentures had a higher risk for bone loss based on the worse periimplant soft-tissue health observed; (3) bleeding on probing was found with pocket depths > or =5 mm in half of the zygomatic implants; (4) prevalence of bone septa is higher in atrophic maxillae, and changes on nasopalatine canal can reduce up to 44.4% of the full length of buccal bone plates; (5) female patients have less medullar bone quantity and connectivity than male patients; (6) transectioning of nutrient vessels is easier and accelerates resorption; (7) stress does not concentrate on maxillary sinus base cortical bone contiguous to trabecular bone; (8) splinted implants receive nine times less load than nonsplinted implants even under oblique loading; (9) implant stability quotient (ISQ) values for implants ranged between 60 and 65; (10) in vivo force transfer to implants is similar between fixed prostheses and overdentures; (11) inclined implants generate better biomechanical responses; (12) masticatory efficiency and bite forces improve in maxillectomized patients who receive obturators with milled bar attachments.


CONCLUSIONS
Sound implant-supported choices for an atrophic maxilla must be made with a thorough understanding of its anatomic and biomechanical factors.
Rossetti
Paulo Henrique Orlato
PH
Discipline of Prosthodontics and Implantology, Sagrado Coração University, Bauru, Sao Paulo, Brazil. phrossetti@uol.com.br
Bonachela
Wellington Cardoso
WC
Rossetti
Leylha Maria Nunes
LM
D001284:Atrophy; D001696:Biomechanical Phenomena; D001862:Bone Resorption / Q000473:pathology / Q000503:physiopathology; D015921:Dental Implants; D005260:Female; D006801:Humans; D008297:Male; D008437:Maxilla / Q000473:pathology* / Q000503:physiopathology; D008439:Maxillary Diseases / Q000473:pathology / Q000503:physiopathology; D013314:Stress, Mechanical
D015921:Dental Implants