title: Impact of diabetes mellitus and metabolic control on bone healing around osseointegrated implants: removal torque and histomorphometric analysis in rats.
abstract: OBJECTIVE
  To evaluate bone healing around dental implants with established osseointegration in experimental diabetes mellitus (DM) and insulin therapy by histomorphometric and removal torque analysis in a rat model.
  
  
  METHODS
  A total of 80 male Wistar rats received a titanium implant in the tibiae proximal methaphysis. After a healing period of 60 days, the rats were divided into four groups of 20 animals each: a 2-month control group, sacrificed at time (group A), a diabetic group (group D), an insulin group (group I), and a 4-month control group (group C), subdivided half for removal torque and half for histomorphometric analysis. In the D and I groups the DM was induced by a single injection of 40 mg/kg body weight streptozotocin (STZ). Two days after DM induction, group I received subcutaneous doses of insulin twice a day, during 2 months. Groups C and D received only saline. Two months after induction of DM, the animals of groups D, C and I were sacrificed. The plasmatic levels of glucose (GPL) were monitored throughout the experiment. Evaluation of the percentages of bone-to-implant contact and bone area within the limits of the implant threads was done by histomorphometric and mechanical torque analysis. Data were analyzed by anova at significant level of 5%.
  
  
  RESULTS
  The GPL were within normal range for groups A, C and I and higher for group D. The means and standard deviations (SD) for histomorphometric bone area showed significant difference between group D (69.34 ± 5.00%) and groups C (78.20 ± 4.88%) and I (79.63 ± 4.97%). Related to bone-to-implant contact there were no significant difference between the groups D (60.81 + 6.83%), C (63.37 + 5.88%) and I (66.97 + 4.13%). The means and SD for removal torque showed that group D (12.91 ± 2.51 Ncm) was statistically lower than group I (17.10 ± 3.06 Ncm) and C (16.95 ± 5.39 Ncm).
  
  
  CONCLUSIONS
  Diabetes mellitus impaired the bone healing around dental implants with established osseointegration because the results presented a lower percentage of bone area in group D in relation to groups C and I resulting in a lowest torque values for implant removal. Moreover, insulin therapy prevents the occurrence of bone abnormalities found in diabetic animals and osseointegration was not compromised.
authors.affiliation: Department of Diagnosis and Surgery, UNESP-Univ Estadual Paulista, Araraquara Dental School, Araraquara, São Paulo, Brazil.
authors.forename: Rafael Scaf
authors.initials: RS
authors.lastname: de Molon
authors.forename: Juliana Aparecida Najarro Dearo
authors.initials: JA
authors.lastname: Morais-Camilo
authors.forename: Mario Henrique Arruda
authors.initials: MH
authors.lastname: Verzola
authors.forename: Rafael Silveira
authors.initials: RS
authors.lastname: Faeda
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Pepato
authors.forename: Elcio
authors.initials: E
authors.lastname: Marcantonio
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D015921:Dental Implants; D003764:Dental Materials / Q000737:chemistry; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology* / Q000517:prevention & control; D004195:Disease Models, Animal; D007004:Hypoglycemic Agents / Q000008:administration & dosage / Q000627:therapeutic use; D007279:Injections, Subcutaneous; D007328:Insulin / Q000008:administration & dosage / Q000627:therapeutic use; D008297:Male; D016348:Osseointegration / Q000502:physiology*; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D013311:Streptozocin; D013977:Tibia / Q000187:drug effects / Q000473:pathology / Q000601:surgery; D014025:Titanium / Q000737:chemistry; D019415:Torque; D014945:Wound Healing / Q000502:physiology
chemical_list: D001786:Blood Glucose; D015921:Dental Implants; D003764:Dental Materials; D007004:Hypoglycemic Agents; D007328:Insulin; D013311:Streptozocin; D014025:Titanium