International Journal of Oral Implantology, 01/2012

Purpose: To compare bone resorption around implants immediately loaded and restored using definitive abutments versus provisional abutments later replaced by custom-made abutments up to 12 months after implant placement. Materials and methods: 28 patients with partial edentulism were selected for a two-implant supported immediate restoration and randomised to provisional abutment (PA) and definitive abutment (DA) groups (14 patients for each group). In the PA group, implants were immediately restored using a platform-switched provisional titanium abutment. In the DA group, definitive platform-switched titanium abutments were tightened. In both groups, a provisional restoration was adapted, avoiding occlusal contacts. All implants were definitively restored after 3 months. In the PA group, patients underwent the standard prosthetic protocol: the abutments were removed and impressions were made directly on the implant platform. In the DA group, patients underwent the 'one abutment at one time' protocol: impressions were made of the abutments using a retraction cord. Peri-implant marginal bone levels were assessed immediately after surgery, and at 6- and 12-month follow-up examinations. Results: At the 12-month follow-up no implant failed. In the PA group, peri-implant bone resorption was 0.359 mm after 6 months and 0.435 mm after 12 months. In the DA group, peri-implant bone resorption was 0.065 mm after 6 months and 0.094 mm after 12 months. There were statistically significant differences between the two groups for peri-implant bone level changes at the 6-month (P 0.001) and the 12-month (P 0.001) follow-up: 0.294 mm (CI 95% 0.276; 0.312) and 0.341 mm (CI 95% 0.322; 0.36), respectively. Conclusions: Within the limits of this study, it can be suggested that the non-removal of abutments placed at the time of surgery results in a statistically significant reduction of the crestal bone resorption around the immediately restored implants in cases of partial edentulism, however a difference of 0.3 mm may not have a clinical impact. Keywords: dental abutments, dental implants, immediate loading, marginal bone levels

Purpose: To evaluate whether 6 mm-long by 4 mm-wide dental implants could be an alternative to at least 10 mm-long implants placed in bone augmented with bone substitutes in posterior atrophic jaws. Materials and methods: Twenty patients with bilateral atrophic mandibles and 20 patients with bilateral atrophic maxillae, having 5 to 7 mm of bone height above the mandibular canal or below the maxillary sinus, were randomised according to a split-mouth design to receive one to three 6 mm-long and 4 mm-wide implants or at least 10-mm long implants in augmented bone at two centres. Mandibles were vertically augmented with interpositional equine bone blocks and resorbable barriers, and implants were placed after 3 months. Maxillary sinuses were augmented with particulated porcine bone via a lateral window and implants were placed simultaneously. All implants were submerged and loaded, after 4 months, with provisional prostheses. Four months later, definitive screw-retained metal-ceramic prostheses were delivered. Outcome measures were prosthesis and implant failures, any complication, time needed to fully recover mental nerve function (only for mandibular implants) and patient preference. Results: All screened patients had sufficient bone width to support 4 mm-diameter implants. Patients were followed up to 5 months post-loading and none dropped out. There were no statistically significant differences in graft, implant or prosthesis failures, though significantly more intra- and postoperative complications occurred at grafted sites. Fourteen complications occurred in 12 patients at augmented sites versus none at short implants. All complications occurred before loading. Three complications were associated with the failure of the mandibular grafts (15%), determining the failures of 3 implants in one patient and 2 prostheses could not be delivered. One patient was re-grafted and 2 patients received short implants instead. Apart from those complications associated with graft failures, there were 4 perforations of the sinus membrane during sinus lifting and 7 temporary lower lip paraesthesiae lasting up to 4 days with no long-term consequences for the patients. All maxillary implants and prostheses were successful. All 20 patients treated with mandibular implants and 15 patients treated with maxillary implants preferred short implants, whereas 5 patients treated with maxillary implants described both procedures as equally acceptable. These differences were statistically significant. Conclusions: Short-term data (5 months after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone. Short implants might be a preferable choice to bone augmentation, especially in posterior mandibles since the treatment is faster, cheaper and associated with less morbidity. However, 5- to 10-year post-loading data are necessary before making reliable recommendations. Keywords: bone substitutes, inlay graft, short dental implants, sinus lift, vertical augmentation

Aim: To report retrospectively on the 3-year follow-up results in the rehabilitation of completely edentulous atrophied maxillae using extra-maxillary zygomatic implants. Materials and methods: This retrospective report includes an initial cohort of 39 patients (30 women and 9 men), with a mean age of 53 years, which were followed up for 3 years. The patients were rehabilitated with 39 fixed prostheses and 169 implants (92 zygomatic and 77 regular implants). Final abutments were delivered at surgery stage and a provisional fixed dental prosthesis was manufactured and attached to the implants on the same day as surgery, achieving immediate function. Outcome measures were prosthesis success, implant success, complications, probing pocket depths (PPDs) and marginal bone levels (only for conventional implants). Data were analysed with descriptive and inferential analyses. Results: Five patients dropped out of the study and 1 patient died after 30 months of follow-up due to causes unrelated to the oral rehabilitation. No prosthesis or implant was lost, though 1 implant presented mobility at the 1-year follow-up but remained stable on subsequent follow-ups. Six complications occurred (18%): 5 cases of sinusitis in 5 patients preoperatively diagnosed with sinusitis and whose sinus membrane was disrupted during surgery, and 1 oro-antral communication. Median PPD values were 3 mm in all follow-up appointments (2, 4 and 6 months, 1, 2 and 3 years), comparable to the values of probing depths assessed for standard implants. Conclusions: Within the limitations of this study, the medium-term outcome (3 years) indicates that severely atrophied completely edentulous maxilla rehabilitations supported by immediately loaded zygomatic implants are viable. Keywords: All-on-4, completely edentulous, dental implants, immediate loading, zygoma implants

Purpose: To evaluate the clinical outcome of 2 implants placed flapless in fully edentulous mandibles and immediately restored with a metal-resin screw-retained cross-arch prosthesis 1 year after loading. Materials and methods: Eighty consecutive patients were recruited. To be immediately loaded, implants had to be inserted with a minimum torque of 80 Ncm. Outcome measures, evaluated by two independent assessors, were prosthesis and implant failures, complications, marginal bone level changes, implant stability quotient (ISQ) values and patient satisfaction. Results: Flaps were raised in 7 patients. Twelve implants in 7 patients did not reach the planned insertion torque. Four implants in 3 patients were immediately replaced by larger diameter implants and achieved the desired torque, whereas the remaining implants were immediately loaded anyway. Two implants failed early in 2 patients, but were successfully replaced and their prostheses remade. One month after loading, 72 (90%) patients declared to be completely satisfied with the therapy, 7 (9%) partially satisfied and 1 (1%) unsatisfied. One year after loading, all prostheses were in function, though one patient did not attend the 1-year control. Eight (10%) complications occurred, all successfully treated. After 1 year, the mean marginal bone loss was 0.3 mm and mean ISQ values decreased from 75.4 to 72.4. Conclusions: These short-term results at 1 year after loading suggest that immediately loaded mandibular cross-arch fixed prostheses can be supported by only 2 dental implants. Longer follow-ups (around 10 years) are needed to know the prognosis of this treatment modality. Keywords: cohort study, dental implants, flapless, immediate loading

Purpose: To evaluate the outcome of two freestanding implants immediately loaded retaining an existing mandibular complete denture in elderly edentulous patients up to 1 year after loading. Materials and methods: 42 patients with a mean age of 76.5 years (range 71 to 89) were selected for stabilising their mandibular complete denture with two implants placed mesial to the mandibular canine position bilaterally. Individual ball abutments were connected and torqued at 30 Ncm and the existing complete denture was immediately attached. No postoperative limitations to chewing function were given. The patients were evaluated clinically and radiographically at implant placement and at 6- and 12-month follow-up examinations. Results: At the 12-month follow-up no implant failed. Peri-implant bone resorption was 0.203 mm (CI 95% 0.322; 0.086) after 6 months and 0.298 mm (CI 95% 0.425; 0.173) after 12 months. Of the 42 cases, 3 had major prosthetic complications and 5 patients required minor extra maintenance appointments. Conclusions: Within the limits of this study, it can be suggested that the immediate loading of two unsplinted implants retaining the existing complete mandibular denture in elderly patients can result in favourable implant survival and peri-implant bone healing, however larger and longer follow-ups of 5 years or more are needed. Keywords: ball abutments, freestanding implants, immediate loading, mandibular overdenture

Purpose: To retrospectively evaluate the outcome of immediately loaded cross-arch fixed dental prostheses 6 months after loading. A second aim was to compare survival rates of implants placed in healed versus fresh extraction sites. Materials and methods: In total, 113 consecutive patients about to have their maxillae rendered fully edentulous (mean extractions per patient: 6.7 teeth) received four to eight implants each (total number = 675) which were immediately placed in healed sites (323 implants, 47.9%) or fresh sockets (352 implants, 52.1%). Immediate loading of provisional prostheses was performed and all patients were followed up for 6 months. The success criteria included prosthesis success, assessment of individual implant stability and complications. Results: No patients dropped out and all 113 patients received definitive fixed prostheses after 6 months of loading. The overall implant survival rate after 6 months was 99.1%. Six implants were lost in 6 patients (5.3%). Five of them were inserted in fresh extraction sockets (1.4%) and one in a healed site (0.3%). No significant difference (P = 0.1621) was found for implants placed in healed sites versus fresh extraction sites. Ten patients had fractures of the provisional prostheses as complications. Conclusions: Immediate implant placement and loading resulted in high implant as well as prosthetic survival rates. Placement in healed or fresh extraction bone sites may not influence implant survival. Keywords: cross-arch fixed dental prosthesis, immediate implant placement, immediate loading, maxillary edentulous patients

Purpose: To reach through intense interactions among a group of renowned experts a better view of the treatment options available for marginal bone maintenance and eventual inflammation and/ or loss around oral implants. The working group was intended to generate guidelines useful for the clinical community at large. Format: Two days of interactive presentations and discussions on the basis of review papers delivered beforehand by the participants. Each of the participants was asked to focus on a particular aspect of the global theme - maintenance of marginal bone around oral implants and treatment options - while keeping a global view for further discussion. From the prepared reviews only the conclusions were presented at the meeting as an introduction for the discussions. The reviews were distributed among all participants beforehand and, if needed, the other participants could draw the attention of the author on missing aspects and references prior to the meeting. A general consensus was formulated. The consensus was amended during the two days of the meeting until a unanimous opinion was reached. Minority statements could be considered. The review papers were not required to be systematic reviews (time and means were lacking) but they were to be valuable critical analyses considering the internationally recognised expertise of the authors.

Purpose: The aim of this narrative review was to explore and discuss marginal bone loss around transmucosal oral implants and the related incidence of this biologic complication. Results: Treatment with osseointegrated implants is most often successful and improves the quality of life for the patient. At present only limited data are available to evaluate long-term technical and biological complications. When peri-implant tissue destruction occurs, little is known about the initiating process. Possible factors of relevance for the initiation and progression of peri-implantitis are discussed. Periodontitis, smoking and a variety of local factors are among the most plausible putative reported risk factors. Also, oral hygiene and the inability to clean the reconstruction were reported. The unit for reporting incidence of peri-implant bone loss varies in different studies between implants and patients. Since there seems to be a clustering effect, and implants in the same mouth cannot be considered independent from each other, it is recommended to use the patient as a unit. The different cut-off values for clinical parameters reported in different studies will exert a significant influence on the magnitude of the reported incidence of peri-implantitis. It is suggested that the composite variables including bone loss >=2 mm, compared to initial radiographs at delivery of the prosthetic device, in combination with bleeding on probing should be interpreted as a 'red flag' for the clinician to critically evaluate if any intervention is indicated in the individual case. Conclusion: Until more solid scientific evidence has been made available, it is likely that the academic controversy in relation to peri-implant bone loss and peri-implantitis will continue. Keywords: aetiology, human, incidence, peri-implantitis, review

Purpose: To identify the most effective interventions for treating peri-implantitis around osseointegrated oral implants. Materials and methods: The Cochrane Oral Health Group's Trials Register, CENTRAL, MEDLINE and EMBASE were searched up to the 9th of June 2011 for randomised controlled trials (RCTs) comparing agents or interventions for treating peri-implantitis around oral implants. Primary outcome measures were implant failure, radiographic marginal bone level change, complications and side effects, and recurrence of peri-implantitis. Screening of eligible studies, assessment of the methodological quality of the trials and data extraction were conducted in duplicate and independently by two review authors. The statistical unit was the patient and not the implant unless the clustering of the implants within the patients had been taken into account. Results were expressed as random-effects models using mean differences for continuous outcomes and risk ratios for dichotomous outcomes with 95% confidence intervals (CI). Results: Fifteen eligible trials were identified, but six were excluded. The following interventions were compared in the nine included studies: different non-surgical interventions (five trials), adjunctive treatments to non-surgical interventions (one trial), and different surgical interventions (two trials) and adjunctive treatments to surgical interventions (one trial). Follow-up ranged from 3 months to 4 years. No study was judged to be at low risk of bias. Statistically significant differences were observed in two small single trials judged to be at unclear or high risk of bias. After 4 months, adjunctive local antibiotics to manual debridement in patients who lost at least 50% of the bone around implants showed improved mean probing attachment levels (PAL) of 0.61 mm (95% CI 0.40 to 0.82) and reduced probing pockets depths (PPD) of 0.59 mm (95% CI 0.39 to 0.79). After 4 years, patients with peri-implant infrabony defects >3 mm treated with Bio-Oss and resorbable barriers showed an improvement of 1.4 mm for PAL (95% CI 0.24 to 2.56) and PPD (95% CI 0.81 to 1.99) compared to patients treated with a nanocrystalline hydroxyapatite. Conclusions: There is no reliable evidence suggesting which could be the most effective interventions for treating peri-implantitis. This is not to say that currently used interventions are not effective. A single small trial at unclear risk of bias showed that the use of local antibiotics in addition to manual subgingival debridement was associated with a 0.6 mm additional improvement in PAL and PPD over a 4-month period in patients affected by severe forms of peri-implantitis. Another small single trial at high risk of bias showed that after 4 years, improved PAL and PPD of about 1.4 mm were obtained when using Bio-Oss with resorbable barriers compared to a nanocrystalline hydroxyapatite in peri-implant infrabony defects. There is no evidence from four trials that the more complex and expensive therapies were more beneficial than the control therapies, which basically consisted of simple subgingival mechanical debridement. Follow-up longer than 1 year suggested recurrence of peri-implantitis in up to 100% of the treated cases for some of the tested interventions. As this can be a chronic disease, re-treatment may be necessary. Larger well-designed RCTs with follow-ups longer than 1 year are needed.

Purpose: To review and discuss current literature on the use of systemically administered or locally delivered antibiotics in the treatment of peri-implantitis. Materials and methods: A literature search was conducted using MEDLINE through the PubMed database of the US National Library of Medicine using studies up to 2011. Studies on the microbiology of peri-implantitis lesions were hand selected. Results and conclusions: Two studies on the use of systemically administered antibiotics in the treatment of peri-implantitis were identified. Both studies involved a case series without controls. Five studies on locally delivered antibiotics were found. In all cases, local antibiotics were used in conjunction with mechanical debridement and chemical disinfection with antimicrobial agents such as chlorhexidine digluconate or hydrogen peroxide. The additional effects of local antibiotics were noted in all studies but were in general moderate. This may in part be due to the selection of patients with advanced deep pockets and advanced bone loss. The current available scientific information on the use of locally or systemically administered antibiotics is insufficient to allow any firm specific recommendations for the use of these drugs. Local application of minocycline or doxycycline as an adjunct to mechanical debridement and irrigation with an antimicrobial agent may be effective in moderately deep lesions. Surgical access by full-thickness flap surgery in deeper lesions is probably necessary to halt the progression of bone loss. No sound scientific basis is available for the use of systemic antibiotics. There is an urgent need for randomised clinical trials on the use of antibiotics in the treatment of peri-implantitis. Proper periodontal infection control in dentate patients before implants are installed and frequent supportive implant care represent effective measures to reduce the risk of future infections and their complications around oral implants. Keywords: antibiotics, peri-implantitis, review

Purpose: Peri-implantitis is a growing problem because of the increasing number of patients rehabilitated with oral implants. Predictors of susceptibility to peri-implantitis and pharmacological agents for the treatment of inflammatory peri-implantitis are of significant interest to the practicing community. The goal of this paper is to review the current literature relating to the impact of genotypes and immune reactivity on peri-implant inflammation and to identify the potential use of anti-inflammatory and immunomodulatory drugs. Materials and methods: A MEDLINE search of the relevant literature was performed and all related articles were evaluated. Results: There was little support in the literature for a specific genotype or phenotype of immune reactivity that could be reliably used as an indicator of susceptibility to peri-implant disease. Furthermore, no currently available anti-inflammatory drugs were identified that could be used long term for the treatment of inflammatory peri-implantitis. New pathways for the control of inflammation have been identified that have the potential for new pharmacologic therapies. The basis for these new discoveries is reviewed in some detail. Conclusions: While there are varying reports of associations of specific genotypes with peri-implantitis, the studies are inconsistent and generally underpowered precluding any interpretable pattern. Inflammatory peri-implantitis is associated with increased local inflammation, but no consistent systemic inflammatory markers have been identified. To date, no safe and effective anti-inflammatory therapy is known for the treatment of peri-implantitis. However, a new class of molecules in development for the active regulation and resolution of inflammation shows theoretical promise for the treatment of inflammatory lesions. Keywords: genetic markers, inflammation, lipoxins, peri-implantitis, resolvins

Purpose: To review the literature on the surgical treatment of peri-implantitis. Materials and methods: The potentially relevant literature was preliminarily assessed via scoping searches to find the most appropriate search terms and the most efficient Boolean search algorithm. The present authors identified 33 reports on subjects with osseointegrated implants, with a pathological condition compatible with the definition of 'peri-implantitis', describing the surgical treatment with a follow-up of at least 6 months. Results and conclusions: The 14 case reports, 10 case series and 9 papers on 6 comparative studies illustrate the diversity of approaches and the current uncertainties concerning the surgical treatment of peri-implantitis. All current approaches include the elevation of a mucoperiosteal flap and the removal of the peri-implant inflammatory granulation tissue. Surfaces have been subjected to cleaning with carbon or plastic curettes, ultrasonic scalers, air-polishing devices using sodium bicarbonate or glycine powder, to irradiation with hard or soft laser light, implantoplasty and/or the application of acids or various antimicrobial agents. The majority of protocols include the systemic administration of an antibiotic and chlorhexidine rinses. Autogenous bone, allogenic decalcified freeze-dried bone, xenogenic bone mineral, phytogenic calcium carbonate, hydroxyapatite or tri-calcium phosphate have been used in an attempt to fill peri-implant defects and regenerate bone. Expanded polytetrafluoroethylene, collagen, and resorbable synthetic membranes have been placed to cover the area. The currently available evidence does not allow any firm specific recommendations for the surgical therapy of peri-implantitis. The following elements of therapy seem to be beneficial: surgical access by a full-thickness flap, thorough cleaning of the contaminated implant surfaces, systemic administration of an antibiotic and oral chlorhexidine rinse. The stabilisation of the defect with a bone substitute may also be advantageous. Keywords: peri-implantitis, review, surgical treatment

Purpose: The objective of this review was to summarise current evidence with regard to the decontamination of implant surfaces by mechanical, chemical and physical methods in the presence of marginal bone loss arising from peri-implant infections. Materials and methods: A PubMed search identified studies and publications dealing with 'periimplantitis', 'treatment', 'surface decontamination', 'laser application' 'air-abrasive treatment' and 'photodynamic therapy'. Only studies in international peer-reviewed journals were selected for further evaluation; case reports were not included. Results: Several therapeutic approaches were identified such as mechanical treatment, antiseptics and air-abrasive treatment, photodynamic treatment, and laser applications. Since treatment of infected surfaces with air-powder ± citric acid, gauze soaked with saline + citric acid or gauze soaked with chlorhexidine led to similar results in experimental studies, cotton pellets with saline may be adequate for cleaning micro-rough surfaces. Antimicrobial photodynamic therapy can effectively reduce the prevalence of pathogens on implant surfaces, but the clinical benefits remain unknown. The increase in temperature of the implant surface caused by the CO2 laser poses a risk. The Er:YAG laser is considered to possess the best properties for implant surface decontamination. In vivo, no single method of surface decontamination (chemical agents, air abrasives or lasers) was found to be superior. In several animal experiments, thorough cleaning of the infected implant surfaces and implantation of these previously infected devices into freshly prepared sites resulted in re-osseointegration, while currently there are no controlled clinical trials where re-osseointegration has been demonstrated in patients. Conclusions: For decontamination of the infected implant surfaces, rinsing with saline (or cleaning with cotton pellets soaked with sterile saline) and air-abrasive treatment seem to work. Laser decontamination of the surface does not improve healing results. Non-surgical therapy of implants with peri-implantitis does not lead to successful treatment outcomes. Keywords: air-abrasive treatment, antibiotics, antiseptics, decontamination, Er:YAG laser, implant surface, non-surgical periodontal therapy, osseointegration, peri-implantitis, periimplant mucositis, periodontal surgery, review, surface chemistry

Purpose: The quality and stability of the soft tissue-implant interface is most likely of paramount importance for the preservation of marginal bone and for the long-term prognosis of oral implants. The aim of the present review was to screen existing data in the literature concerning the influence of transmucosal components' composition, type, design and disconnection on peri-implant tissues. Results: The influence of the type of implant system (one-piece or soft tissue level implants versus two-piece or bone level implants) has been poorly studied in humans, and data from animal studies are controversial; both concepts demonstrated comparable long-term stability of peri-implant tissues. The chemical composition of abutments has been mostly studied in animals, with the conclusion that only a few materials (namely titanium, aluminium and zirconium oxides) allow the proper formation of a soft tissue interface. However, there is a severe lack of information about the clinical impact of this parameter, as well as of surface contamination of abutments. Mobility of transmucosal components has been shown to increase marginal bone loss in animals, while the influence of abutment disconnection is more controversial. Only one clinical study suggests that a 'one abutment - one time' technique preserves marginal bone. Studies investigating the influence of platform switching suggest that using an abutment narrower than the implant's platform could have a positive effect on the fate of marginal bone. But those studies are extremely heterogenous and their results controversial. Conclusion: There is still a severe lack of information about the clinical impact of implant type, of implant/ abutment connection, and of abutment composition and stability on peri-implant bone remodelling. Keywords: abutment disconnection, platform switching, soft tissue-implant interface, transmucosal components

Background: Occlusal overloading is the primary cause of biomechanical implant complications, which include fracture and/or loosening of the implant fixture and/or prosthetic components. It may also disrupt the intricate bond between the implant surface and bone, leading to peri-implant bone loss and eventual implant failure. Purpose: This paper was aimed at identifying and evaluating clinical and radiographic parameters relevant for diagnosing occlusal overloading of oral implants. It also discusses its management in order to prevent peri-implant marginal bone loss. Materials and methods: An electronic literature search for relevant studies, examining the relationship between occlusal overloading and peri-implant bone loss, was conducted in the PubMed database. Clinical human studies published in English with a minimum of 10 implants were included. Results: Seven articles were identified. Occlusal overloading was found to be positively associated with peri-implant marginal bone loss. Conclusion: Preventing occlusal overloading involves conducting comprehensive examinations, treatment planning, precise surgical and prosthetic treatment executions, and regular maintenance. If occlusal overloading occurs, management of biomechanical implant complications and preventing/ treating peri-implant bone loss involves surgical and prosthetic treatment modalities. They include occlusal treatment, repair and replacement of defective prosthetic components, and surgical treatment of the bony craters. Keywords: biomechanics, bone remodelling, implant complications, implant prosthesis, implants, overload, peri-implantitis