title: Changes in the edentulous maxilla with ball and telescopic attachments of implant-retained mandibular overdentures: a 4-year retrospective study.
abstract: OBJECTIVE
  This retrospective study investigated the clinical and radiographic changes in the edentulous maxilla in patients with either ball or telescopic attachments of implantretained mandibular overdentures.
  
  
  METHODS
  Thirty-two completely edentulous patients (21 males and 11 females) received two implants in the canine region of the mandible. New maxillary complete dentures and mandibular overdentures were fabricated. Overdentures were connected to the implants either with ball (group 1, n = 16) or telescopic (group 2, n = 16) attachments. Retention and stability of the maxillary denture as well as mucosal changes of the maxillary ridge were recorded after 4 years of denturewearing. Traced rotational tomograms were used for measurements of maxillary alveolar bone loss. The proportional value between bone areas and areas of reference not subject to resorption was expressed as a ratio (R). Change in R immediately before (T0) and after 4 years (T4) of overdenture insertion was calculated for the anterior and posterior regions of the maxilla.
  
  
  RESULTS
  After 4 years of denture-wearing, maxillary denture retention was significantly higher in group 1 than in group 2, while occurrence of flabby ridges was significantly higher in group 2 than in group 1. The change in R of the anterior region of the maxilla was significantly higher than the change in the posterior region in both groups. Group 2 showed significant anterior residual ridge resorption compared to group 1.
  
  
  CONCLUSIONS
  Telescopic attachments for implant-retained mandibular overdentures are associated with increased maxillary ridge resorption and flabbiness, and decreased maxillary denture retention when compared to ball attachments.
authors.affiliation: Department of Removable Prosthodontics, Faculty of Dentistry, Mansoura University, Egypt. M_syad@mans.edu.eg
authors.forename: Moustafa Abdou
authors.initials: MA
authors.lastname: Elsyad
authors.forename: Ahmed Samir
authors.initials: AS
authors.lastname: Khairallah
authors.forename: Ahmad Fathalla
authors.initials: AF
authors.lastname: Shawky
mesh_terms: D016301:Alveolar Bone Loss / Q000209:etiology*; D019094:Dental Prosthesis, Implant-Supported / Q000009:adverse effects*; D003779:Denture Design; D003834:Denture Precision Attachment / Q000009:adverse effects*; D003781:Denture Retention; D003826:Denture, Complete, Lower / Q000009:adverse effects*; D003828:Denture, Overlay / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007575:Jaw, Edentulous / Q000000981:diagnostic imaging / Q000473:pathology* / Q000628:therapy; D008297:Male; D008437:Maxilla / Q000000981:diagnostic imaging / Q000473:pathology*; D008875:Middle Aged; D009061:Mouth Mucosa / Q000473:pathology; D011859:Radiography; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D013282:Stomatitis, Denture / Q000209:etiology