title: Prospective Clinical and Radiographic Study of Alveolar Ridge Preservation Combining Freeze-Dried Bone Allograft With Two Xenogeneic Collagen Matrices.
abstract: BACKGROUND
  Tooth extractions are followed by significant dimensional changes in the alveolar crest that may preclude implant placement. This randomized, controlled, prospective compares the preservation of soft and hard tissue dimensional changes after alveolar ridge preservation (ARP) using two membranes consisting of collagen matrix (CM) or extracellular matrix (ECM) as barriers over freeze-dried bone allograft (FDBA).
  
  
  METHODS
  Standardized clinical and radiographic measurements of soft and hard tissues were recorded by means of a stent before and 4 months after ARP. The surgery entailed sulcular incisions with minimal flap elevation and repositioning without advancement.
  
  
  RESULTS
  Of 11 patients in the CM group and 12 in the ECM group who completed the study, gingival thickness (GT) increased from 0.1 to 0.2 mm for both groups along with a 0.5-mm decrease in the width of keratinized tissue after healing. Reductions in ridge width were most pronounced on the coronal aspect, 1.8 mm for CM and 2.0 mm for ECM, whereas vertical reduction was most pronounced on the buccal aspect, 0.7 to 1.0 mm. Differences between groups were not statistically significant. However, significant correlation for changes in GT (P = 0.001) and crestal bone width (P = 0.002) with preoperative buccal plate thickness (BPT) was observed.
  
  
  CONCLUSIONS
  Both xenogeneic collagen matrices combined with FDBA were effective in maintaining soft tissues and minimizing ridge resorption in all dimensions after ARP. BPT was an important determinant for amount of change in crestal GT and ridge width.
authors.affiliation: Department of Periodontology, Tufts University School of Dental Medicine, Boston, MA.
authors.forename: Andreas O
authors.initials: AO
authors.lastname: Parashis
authors.affiliation: Department of Periodontology, Tufts University School of Dental Medicine, Boston, MA.
authors.forename: Charles E
authors.initials: CE
authors.lastname: Hawley
authors.affiliation: Department of Public Health and Community Service, Tufts University School of Dental Medicine.
authors.forename: Paul C
authors.initials: PC
authors.lastname: Stark
authors.affiliation: Department of Radiology, Tufts University School of Dental Medicine.
authors.forename: Rumpa
authors.initials: R
authors.lastname: Ganguly
authors.affiliation: Department of Periodontology, Tufts University School of Dental Medicine, Boston, MA.|Deceased; previously, Department of Periodontology, Tufts University School of Dental Medicine.
authors.forename: James B
authors.initials: JB
authors.lastname: Hanley
authors.affiliation: Department of Periodontology, Tufts University School of Dental Medicine, Boston, MA.
authors.forename: Bjorn
authors.initials: B
authors.lastname: Steffensen
mesh_terms: D064591:Allografts / Q000601:surgery; D000539:Alveolar Process / Q000601:surgery; D000540:Alveolar Ridge Augmentation; D003094:Collagen; D006801:Humans; D008567:Membranes, Artificial; D011446:Prospective Studies; D014081:Tooth Extraction; D020390:Tooth Socket / Q000601:surgery
chemical_list: D008567:Membranes, Artificial; D003094:Collagen
keywords: Allografts; collagen; extracellular matrix; ridge preservation; tooth extraction; tooth socket