29. Prosthodontic comparisons

Retrospectively, the study investigated prosthetic survival and complication rates of single implants in 50 periodontally healthy patients after 16-22 years, and evaluated the influence of different prosthetic procedures. Patients with a single implant were recalled for clinical examination. Prosthetic procedures included single-tooth (ST) and CeraOne (CO) abutments supporting a porcelain-fused-to-metal (PFM), all-ceramic (CER), or gold-acrylic (ACR) crown. Prosthetic survival, success, and occurrence of biological, technical, and aesthetic complications were assessed. Procedures were compared by log-rank tests. All implants were functional; however, 15% of abutments and 27% of crowns had been renewed. Replacements were related to technical issues although the main cause was aesthetics. The abutment cumulative survival rate (CSR) differed significantly between ST-PFM (74%), ST-ACR (0%), and CO reconstructions (97%). The crown CSR was significantly lower for ST-ACR crowns (0%) compared with ST-PFM (68%) and CO (81%). Thirty-nine percent of implants remained complication free throughout the mean 18.5 years. Complications required component replacement, and 53% occurred within five years after surgery.

Dierens M et al. Prosthetic survival and complication rate of single implant treatment in the periodontally healthy patient after 16 to 22 years of follow-up. Clin Implant Dent Related Res 2016 18: 117-128.

Q Which of the following paired statements is true?
A ST-ACR had a good abutment cumulative survival rate but a poor crown survival rate
B The crown CSR was significantly higher for ST-ACR crowns compared with ST-PFM
C 39% of implants had complications and 35% needed component replacement within five years after surgery
D The crown CSR was significantly lower for ST-ACR crowns compared with ST-PFM

30. Pro- or anti- biotics?

This double-blind randomised placebo-controlled trial evaluated the effects of probiotic supplements in adjunct to conventional management of peri-implant mucositis. Adult patients with peri-implant mucositis (n=49) had initial mechanical debridement, oral hygiene instruction and a topical oil application (active or placebo) followed by twice-daily intake of lozenges (active or placebo) for 3 months. The active products contained a mix of two strains of Lactobacillus reuteri. Patients were clinically monitored and sampled at baseline and after 1, 2, 4, 12 and 26 weeks. Pocket-probing depth (PPD), plaque index (PI) and bleeding on probing (BOP) were recorded. After 4 and 12 weeks, all clinical parameters were improved in both groups. PPD and BOP were significantly reduced compared with baseline but no significant differences were evident between the groups. The clinical improvements persisted 3 months after the intervention. No major alterations of the subgingival microflora were found and the levels of inflammatory mediators did not differ between the groups. Probiotic supplements did not provide added benefit to placebo.

Hallstrom H et al. Probiotic supplements and debridement of peri-implant mucositis: a randomized controlled trial. Acta Odontologica Scand 2016 74: 60-66.

Q In relation to peri-implantitis:
A Significant alterations of the subgingival microflora were found
B Mechanical plaque removal was of minimal use
C Probiotics reduced inflammation and reduced pocket depth compared to a placebo
D Probiotics had no identifiable benefits

31. Risk factors examined

The purpose of this retrospective clinical study was to explore the association between possible risk factors and early implant failure by evaluating 142 participants who received 276 external connection BTI implants between 2007 and 2011. Participant variables (age, gender, systemic disease, tobacco use, alcohol consumption, bruxism, and degree of periodontal disease), implant variables (type of edentulism, localisation, area, diameter, length, and bone quality), intervention variables (expansion mechanisms, sinus augmentation techniques, bone regeneration, and implant insertion), and postoperative variables (presence of pain/inflammation at one-week post-surgery) were studied. Analysis helped determine the relative influence of variables on early implant failure. Early implant failure was significantly associated with the males, severe periodontal disease, short implants, expansion technique and postoperative pain/inflammation at one-week post-surgery. Early dental implant failure is more frequent in men and in individuals with severe periodontal disease, short implants, pain/inflammation at one-week post-surgery or bone expansion treatment.

Olmedo-Gaya MV et al. Risk factors associated with early implant failure: A 5-year retrospective clinical study. J Prosthetic Dent 2016 115: 150-155.

Q Which of the following sets of factors are likely to lead to the greater chance of early implant failure?
A Women in whom expansion technique are used and who suffer postoperative pain/inflammation
B Men with severe periodontal disease and short implants
C Women with good oral health who experienced pain one-week post procedure
D Patients of either gender with small diameter implants

32. Bisphosphonates and implants

A systematic review and meta-analysis were accomplished to assess whether bisphosphonate therapy can decrease the success rate of dental implants. The PubMed (Medline) database was used to search for articles published up until February 22, 2014. The combinations of search terms resulted in a list of 256 titles; 14 finally met the inclusion criteria. Eight studies (six retrospective and two prospective) were included in the meta-analysis, with a total of 1,288 patients (386 cases and 902 controls) and 4,562 dental implants. According to the number needed to harm, over 500 dental implants are required in patients receiving bisphosphonate treatment to produce a single implant failure. The results show that dental implant placement in patients receiving bisphosphonates does not reduce the dental implant success rate. Conversely, such patients are not without complications, and risk evaluation therefore must be established on an individualised basis, as one of the most serious though infrequent complications of bisphosphonate therapy is bisphosphonate-related osteonecrosis of the jaws.

Ata-Ali J et al. What is the impact of bisphosphonate therapy upon dental implant survival? A systematic review and meta-analysis. Clin Oral Implants Res 2016 27: e38-46.

Q In patients taking bisphosphonates:
A Implant placement is not advised at all
B Individual case selection is crucial for implant success
C Bisphosphonates should be discontinued for six months after implant placement
D Ideally all teeth should be replaced by implants