29. Guidance for guided bone

The aim of this research was to determine whether or not implants associated with guided bone regeneration (GBR) due to peri-implant defects show the same survival and success rates as implants placed in native bone without defects. Patients with a minimum of two submerged dental implants: one suffering a dehiscence or fenestration defect during placement and undergoing simultaneous guided bone regeneration (test group), versus the other entirely surrounded by bone (control group) were treated and monitored annually for three years. Complications with the healing procedure, implant survival, implant success and peri-implant marginal bone loss were assessed. Seventy-two patients and 326 implants were included (142 test, 184 control). One hundred and twenty-five dehiscences (average height 1.92mm+/-1.11) and 18 fenestrations (average height 3.34mm+/-2.16) were treated. At 3 years post-loading, implant survival rates were 95.7% (test) and 97.3% (control) and implant success rates were 93.6% and 96.2%, respectively. Implants with peri-implant defects treated with guided bone regeneration exhibited similar survival and success rates and peri-implant marginal bone loss to implants without those defects; but larger scale studies are needed.

Aloy-Prosper A et al. Dental implants with versus without peri-implant bone defects treated with guided bone regeneration. J Clin Experimental Dent 2015 7:e361-368.

Q Is it true that?

A Peri-implant defects are largely caused by GBR application

B Patients with a minimum of two submerged dental implants are a contraindication for GBR

C Implants with peri-implant defects treated with GBR exhibited similar survival and success rates to implants without those defects

D Implants with dehiscences are unlikely to survive more than three years

30. Over and under

This work aimed to confirm whether implant supported overdentures are a good treatment option for edentulous patients and offer an improvement in quality of life compared with traditional complete dentures. Three groups were created: a validation group (n=57); a control group of patients with complete dentures (n=56); and a study group of patients with implant-supported overdentures (n=80). The study also validated the Oral Health Impact Profile-20 questionnaire. The OHIP-20 proved to be a valid instrument and provided reliable assessment of health-related quality of life. The control and study groups proved comparable, showing socio-demographic homogeneity. For patients with overdentures, these restorations had significantly lower impact on quality of life, both generally and for each individual questionnaire item, and much higher satisfaction than patients wearing dentures; both sets of data showed a direct linear relationship, so that as the level of impact on quality of life increased, perceived oral satisfaction worsened. Patients rehabilitated with implant supported overdentures presented significantly lower levels of impact on their quality of life and significantly higher oral satisfaction than patients with conventional complete prostheses.

Fernandez-Estevan L et al. Oral health-related quality of life of implant-supported overdentures versus conventional complete prostheses: Retrospective study of a cohort of edentulous patients. Medicina Oral, Patologia Oral y Cirugia Bucal 2015 20:e450-458.

Q Implant supported overdentures:

A Had a high impact on quality of life

B Were not as well tolerated as conventional removable dentures

C Had a low impact on quality of life

D Are not appropriate for patients with a poor quality of life

31. Replant or implant?

Although nonsurgical initial root canal treatment and retreatment have high success rates, periapical disease can remain. The survival rates of two surgical procedures; intentionally replanted (IR) teeth and implant-supported single crowns (ISCs) were compared in a systematic review and meta-analysis. The quality of the IR and ISC articles was only moderate. Data for ISCs were much more plentiful than for IR teeth. The weighted mean survival was 88% for IR teeth and 97% for ISCs. Root resorption was reported with a mean prevalence of 11% in the IR studies. A recent study on IR teeth indicated that orthodontic extrusion before intentional replantation improved survival rates. The review concluded that the mean survival of ISCs was significantly higher than IR teeth but that treatment decisions must be based on a wide variety of treatment and patient-specific parameters. Intentional replantation may have a role when ISC is not practicable. Studies using contemporary treatment and analytic methods should be used to identify and measure intentional replanted prognostic and treatment variables.

Torabinejad M et al. Survival of intentionally replanted teeth and implant-supported single crowns: a systematic review. J Endodontics 2015 41: 992-998.

Q Intentionally replanted teeth:

A Are always preferable as natural tissue rather than implant-supported single crowns

B May be more practicable than implant-supported single crowns but have a lower survival rate

C Have a higher survival rate than implant-supported single crowns

D Suffer a rate of root resorption of about 88%

32. Survival rates in oral cancer patients

This study evaluated long-term survival rate and potential influencing factors of dental implants and implant-retained prostheses in oral cancer patients who had undergone surgical tumour resection. A total of 157 patients (mean age 53.7 years) with 830 implants (450 maxilla: 380 mandible) were included; in 55 patients (292 implants), the surgical procedure was followed by additional radiochemotherapy (RCT) before implant placement. Patients were clinically examined every 6 or 12 months according to a standard procedure; 65 implants were lost of which 42 were documented due to patient death. The mean observation period was 121 months and the survival rate was 94.9% at 3 years and 92.5% at 7 years. With an observation period up to 20 years, the cumulative survival rate remained constant after 11 years at 90.8%. RCT was determined as a significant factor influencing the survival rate. Since there was no significant difference in the mortality rate of patients with additional RCT compared to patients who underwent sole ablative surgery, the higher loss ratio is due to a late failure of osseointegration.

Doll C et al. Survival analysis of dental implants and implant-retained prostheses in oral cancer patients up to 20 years. Clin Oral Investigations 2015 19: 1347-1352.

Q Using the results of this study as a guide with which statement would you agree?

A The placement of implants for patients recovering from oral cancer surgery in contraindicated

B The use of radiochemotherapy has no additional effect on implant survival

C The duration of this study makes it difficult to make clinical decisions

D The long term survival rate for implants in oral cancer patients is significantly high