Mammalian cell response and bacterial adhesion on titanium healing abutments: effect of multiple implantation and sterilization cycles.

OBJECTIVE: Multiple implantations of the implant healing abutment (IHA) could adversely impact its surface properties in vivo. Furthermore, the effect of sterilization and reuse of the IHA on soft tissue viability and bacterial contamination has not been extensively studied. The goal of this study was to perform an in vitro analysis of mammalian cell viability and bacterial adhesion on the surfaces of retrieved IHA after single and multiple implantations and repetitive cycles of sterilization. MATERIALS AND METHODS: IHA surface morphology was studied using optical microscopy. Cell viability of gingival fibroblasts (HGF-1) and oral keratinocytes (HOKg) in indirect contact with IHAs was assessed for 3 and 7 days. Immersion in bacterial culture was performed with a polyculture of Streptococcus species for 3 days and Streptococcus species with Fusobacterium nucleatum for 7 days. RESULTS: IHAs exhibited signs of surface damage even after a single exposure to the oral cavity. Fibroblasts did not show a significant preference towards control IHAs over used IHAs, whereas keratinocytes exhibited a significant decrease in viability when exposed to IHAs after multiple implantation cycles as compared with controls. Adherent bacterial count increased with increasing number of IHA implantations for both polycultures. CONCLUSIONS: Reusing of IHAs in vivo promoted surface degradation in addition to adversely impacting host cell viability and oral bacterial attachment in vitro. These findings show IHA reuse might potentially affect its clinical performance. CLINICAL RELEVANCE: Careful consideration should be taken when reusing IHAs in patients because this practice can result in permanent surface changes that might affect soft tissue integration during the healing period and promote bacterial colonization.

Group 3 ITI Consensus Report: Patient-reported outcome measures associated with implant dentistry.

OBJECTIVES: The aim of Working Group 3 was to focus on three topics that were assessed using patient-reported outcome measures (PROMs). These topics included the following: (a) the aesthetics of tooth and implant-supported fixed dental prostheses focusing on partially edentulous patients, (b) a comparison of fixed and removable implant-retained prostheses for edentulous populations, and (c) immediate versus early/conventional loading of immediately placed implants in partially edentate patients. PROMs include ratings of satisfaction and oral health-related quality of life (QHRQoL), as well as other indicators, that is, pain, general health-related quality of life (e.g., SF-36). MATERIALS AND METHODS: The Consensus Conference Group 3 participants discussed the findings of the three systematic review manuscripts. Following comprehensive discussions, participants developed consensus statements and recommendations that were then discussed in larger plenary sessions. Following this, any necessary modifications were made and approved. RESULTS: Patients were very satisfied with the aesthetics of implant-supported fixed dental prostheses and the surrounding mucosa. Implant neck design, restorative material, or use of a provisional restoration did not influence patients' ratings. Edentulous patients highly rate both removable and fixed implant-supported prostheses. However, they rate their ability to maintain their oral hygiene significantly higher with the removable prosthesis. Both immediate provisionalization and conventional loading receive positive patient-reported outcomes. CONCLUSIONS: Patient-reported outcome measures should be gathered in every clinical study in which the outcomes of oral rehabilitation with dental implants are investigated. PROMs, such as patients' satisfaction and QHRQoL, should supplement other clinical parameters in our clinical definition of success.

Effects of decontamination solutions on the surface of titanium: investigation of surface morphology, composition, and roughness.

AIM: To investigate the impact of treatments used to detoxify dental implants on the oxide layer morphology and to infer how changes in morphology created by these treatments may impact re-osseointegration of an implant. MATERIALS AND METHODS: Pure titanium (cpTi) and the alloy Ti6Al4V were subjected to a series of chemical treatments and mechanical abrasion simulating surface decontamination of dental implants. The morphology and roughness of the surface layer before and after treatment with these solutions were investigated with optical and atomic force microscopy (OM, AFM). The solutions employed are typically used for detoxification of dental implants. These included citric acid, 15% hydrogen peroxide, chlorhexidine gluconate, tetracycline, doxycycline, sodium fluoride, peroxyacetic acid, and treatment with carbon dioxide laser. The treatments consisted of both immersions of samples in solution and rubbing with cotton swabs soaked in solution for 1, 2, and 5 min. Cotton swabs used were analyzed with energy dispersive spectroscopy (EDS). RESULTS: The microscopy investigation showed that corrosion and pitting of the samples were present in both metal grades with immersion and rubbing methods when employing more acidic solutions, which had pH <3. Mildly acidic solutions caused surface discoloration when coupled with rubbing but did not cause corrosion with immersion. Neutral or basic treatments resulted in no signs of corrosion with both methods. EDS results revealed the presence of titanium particles on all rubbing samples. CONCLUSION: It was demonstrated in this study that acidic environments coupled with rubbing are able to introduce noticeable morphological changes and corrosion on the surface of both titanium grades.

A videoscope for use in minimally invasive periodontal surgery.

INTRODUCTION: Minimally invasive periodontal procedures have been reported to produce excellent clinical results. Visualization during minimally invasive procedures has traditionally been obtained by the use of surgical telescopes, surgical microscopes, glass fibre endoscopes or a combination of these devices. All of these methods for visualization are less than fully satisfactory due to problems with access, magnification and blurred imaging. CLINICAL INNOVATION: A videoscope for use with minimally invasive periodontal procedures has been developed to overcome some of the difficulties that exist with current visualization approaches. This videoscope incorporates a gas shielding technology that eliminates the problems of fogging and fouling of the optics of the videoscope that has previously prevented the successful application of endoscopic visualization to periodontal surgery. In addition, as part of the gas shielding technology the videoscope also includes a moveable retractor specifically adapted for minimally invasive surgery. DISCUSSION: The clinical use of the videoscope during minimally invasive periodontal surgery is demonstrated and discussed. CONCLUSION: The videoscope with gas shielding alleviates many of the difficulties associated with visualization during minimally invasive periodontal surgery.

The Potential Role of Titanium Allergy in Implant Failure.

Implant bone loss and implant failure are growing concerns. In some cases, a possible factor leading to bone loss may be an allergy to titanium (Ti). In this report, the existing literature on Ti allergy as a factor in implant loss is reviewed, and the current views on its potential role in implant bone loss are discussed. A case report of implant loss and retreatment in a patient with a potential Ti allergy or intolerance is presented and clinically analyzed. The subsequent success of a ceramic implant may support the finding of a Ti allergy or intolerance. Unfortunately, the lack of prospective clinical trials and lack of a reliable test for Ti allergy makes it impossible to clinically verify whether Ti allergy plays a part in implant bone loss.

Minimum criteria for immediate provisionalization of single-tooth dental implants in extraction sites: a 1-year retrospective study of 100 consecutive cases.

PURPOSE: Minimum criteria were used in the placement of 100 consecutive provisional restorations on single-tooth dental implants placed into extraction sites within 3 days of surgery. MATERIALS AND METHODS: Provisional restorations were placed on 4.1- and 4.8-mm diameter standard ITI (Straumann, Waltham, MA) implants in the anterior mandible and maxilla in 100 treatment sites over a 3-year period. Provisionals were placed despite low insertion torque values of 15 N-cm or 50 implant stability quotient using radiofrequency analysis. Implants had final impressions for definitive restorations done 8 to 12 weeks after implant placement. All patients were recalled 1 year after restoration and evaluated according to parameters suggested by Albrektsson et al (Int J Oral Maxillofac Implants 1:11, 1986). RESULTS: One implant was not osseointegrated. The remaining implants were judged successful at the 1-year recall appointment. CONCLUSION: Immediate provisionalization of implants placed into fresh extraction sites can be effective even when minimal provisionalization criteria are met.

Bone loss around implants-is it metallosis?

Most would agree that the etiology of dental implant failure is related to oral biofilm. At present one group of scientists and clinicians feel that biofilm is solely responsible for bone loss around the devices. However, there is strong evidence that particles and ions of titanium released into the surrounding tissues by the action of biofilm and/or mechanical forces, a process termed metallosis, can be responsible for bone loss around some dental implants. These findings are reinforced by similar responses found around failed metal on metal joint prostheses. Both possible etiologies are discussed in detail in this commentary.

Bone changes around early loaded chemically modified sandblasted and acid-etched surfaced implants with and without a machined collar: a radiographic and resonance frequency analysis in the canine mandible.

PURPOSE: The purpose of this study was to evaluate the radiographic bone level and stability changes around early loaded chemically modified sandblasted and acid-etched implants with and without a machined collar. MATERIALS AND METHODS: Seventy-two chemically modified sandblasted and acid-etched implants 4.1 mm in diameter and 8 mm in length were placed in six dogs. Thirty-six implants had no machined collar (NMC) and 36 had a 2.8-mm machined collar (MC). Resonance frequency measurements were obtained at placement and weekly for 3 weeks. All implants were loaded 21 days after surgery. Standardized periapical radiographs were obtained at baseline, at 3 weeks, and at 3, 6, 9, and 12 months. The radiographs were randomized and digitized, and linear measurements of the distance from the first bone-to-implant contact to the shoulder of the implant were performed at the mesial and distal aspects of each implant. For statistical analysis, mixed-model repeated-measures analysis of variance was used. RESULTS: All implants achieved hard and soft tissue integration clinically and radiographically and were clinically immobile. From placement to week 3, the mean implant stability increased for MC implants by more than 5 ISQs and for NMC implants by more than 7 ISQs. Radiographically, there were significant differences between treatment groups beginning at 3 months. After 12 months of loading, the MC implants presented a mean bone loss of 1.00 mm and the NMC implants presented a mean bone gain of 0.11 mm. CONCLUSIONS: Chemically modified sandblasted and acid-etched implants without a machined collar presented bone gain, and implants with a machined collar showed bone loss after a 1 year following early (21-day) loading. The tendency toward a coronal apposition of bone observed under these conditions may be attributed to the osteoconductive properties of the chemically modified surfaces of these implants and to the absence of the machined collar.

Laser identification of residual microislands of calculus and their removal with chelation.

BACKGROUND: During videoscope-assisted minimally invasive surgery which uses a high magnification videoscope to treat periodontal defects, small areas resembling calculus are detected remaining on root surfaces following scaling. These are clinically termed microislands of calculus, which are removed by the use of a chelating agent. This material has not been verified as calculus and the ability of a chelating agent to remove calculus has not been proven. The purpose of this ex vivo study is to verify if the material is calculus and to determine if calculus is removed with a chelating agent. METHODS: Extracted teeth (n = 22) with heavy calculus on root surfaces were selected. A 5-mm2 area containing calculus was scribed on each root. Digital videoscope images were made of the marked areas using only white light and also with only a 655-nm diode laser that causes calculus to fluoresce. The marked areas were root planed until no calculus was visible with 3.5× surgical loupes. Digital images were again made. The test area was then burnished with a chelating agent (EDTA) for 30 seconds and images again made. Using the images, the percentage of the marked root surface containing calculus was calculated. RESULTS: Calculus remained on the roots surfaces after they were judged to be clean using 3.5× loupe magnification. Remaining calculus was reduced after burnishing for 30 seconds with EDTA. CONCLUSIONS: Calculus remains on root surfaces judged to be calculus free using surgical loupes for visualization. Small areas of calculus are reduced or eliminated with a chelating agent.

Effects of multiple implantations of titanium healing abutments: Surface characteristics and microbial colonization.

OBJECTIVE: Very few studies have investigated dental implant components involved in the early stage of healing, especially the implant healing abutment (IHA), despite its vital role in soft tissue contouring and shaping after implant placement. Although these components are labelled by the manufacturer for "single-use only," it is a common clinical practice to clean, sterilize, and reuse them. METHODS: In the present study, IHAs after single and multiple implantations were retrieved as per standard procedures, and biological material isolated from the surface was subjected to 16S rRNA sequence analysis. The microbiome analysis was followed by cleaning and sterilization in order to replicate clinical sterilization techniques. Following sterilization, retrievals were subjected to surface characterization with optical and scanning electron microscopy to investigate surface features, and electrochemical testing was performed to evaluate corrosion behavior. RESULTS: The microbiota was comprised of early colonizers including Streptococcus species and secondary anaerobic colonizers such as Fusobacterium, Capnocytophaga, and Prevotella species. The surface analysis revealed that irrespective of the cleaning and sterilization techniques, the pristine, homogeneous surface of the new, unused IHAs could not be restored. Both single and multiple-use IHAs had severe surface changes including discoloration, major abrasions, biological contamination, and the IHA retrievals exhibited higher corrosion rate as compared to control specimens. SIGNIFICANCE: Reusing IHAs multiple times may not be a prudent practice as the microbial colonization and surface changes caused by using this component multiple times may affect the performance of IHAs in soft tissue healing.

The positive relationship between excess cement and peri-implant disease: a prospective clinical endoscopic study.

BACKGROUND: Cement-retained restorations are commonly used on dental implants. Residual excess cement after placement of fixed partial dentures has been associated with clinical and radiographic signs of peri-implant disease. The purpose of this study was to explore the relationship between excess dental cement and peri-implant disease using the dental endoscope. METHODS: Thirty-nine consecutive patients with implants exhibiting clinical and/or radiographic signs of peri-implant disease were studied. Patients were enrolled in the study during a 5-year period in a private periodontal practice. Twelve of these patients had similar implants without signs of inflammation; these implants served as controls. There were 20 controls and 42 test implants. All were evaluated using a dental endoscope initially, and all but one implant was evaluated at a 30-day follow-up. Results from both groups were assessed by two trained operators and recorded. RESULTS: None of the controls and all 42 of the test implants had clinical signs of peri-implant disease at initial treatment. Excess cement was found in none of the controls and 34 of the test sites. Thirty days after cement removal, 25 of 33 test sites from which the cement was removed had no clinical or endoscopic signs of inflammation. CONCLUSIONS: Excess dental cement was associated with signs of peri-implant disease in the majority (81%) of the cases. Clinical and endoscopic signs of peri-implant disease were absent in 74% of the test implants after the removal of excess cement.

A prospective study of 3 weeks' loading of chemically modified titanium implants in the maxillary molar region: 1-year results.

PURPOSE: Recent research has demonstrated that modification of implant surface chemistry can influence osseointegration events, leading to increased bone-to-implant contact at earlier times. Clinical studies have been initiated to investigate the potential of modified surfaces to reduce the needed healing period between surgery and prosthesis insertion. The purpose of this prospective clinical study was to evaluate the clinical outcome after 3 weeks of loading single implants with hydrophilic surfaces in the maxillary molar areas. MATERIALS AND METHODS: This prospective two-center clinical trial consecutively included healthy patients who needed an implant in the maxillary molar areas. Drilling was limited to the minimum, most of the site preparation was produced with osteotomes, and screw tapping was never performed. Abutment connection was carried out at 15 Ncm, at 21 (+/- 2) days after surgery, and provisional restorations were fabricated in occlusion. Further abutment tightening at 35 Ncm was performed after 4 to 6 additional weeks, for the definitive restoration. RESULTS: Thirty-five patients were treated. No major adverse events were registered during and/or after surgery. Primary stability was always achieved. At abutment connection, six of the 35 patients reported minor pain, and placement of provisional restorations was postponed for 4 additional weeks. Clinical and radiographic measures were taken at baseline (abutment connection) and at the 1-year follow-up appointment. No patients dropped out, and no implant losses were registered during the first 12 months of observation. No significant differences between baseline and the 1-year examination were recorded for any outcome measure. CONCLUSIONS: These results suggest that, by means of the surgical and restorative technique presented, surface-modified hydrophilic implants are suitable for loading at 3 weeks in maxillary molar areas.

A New Minimally Invasive Approach for Treating Peri-Implantitis.

INTRODUCTION: There is concern that peri-implant bone loss may be associated with a foreign body reaction to cement and/or titanium particles. Previously described treatment approaches aimed at regenerating bone around an implant do not address the removal of these foreign bodies. CASE PRESENTATION: A new videoscope-assisted minimally invasive approach for bone regeneration is described which is designed to remove any tissue embedded foreign bodies before the placement of bone regenerative material. Following removal of the soft tissue adjacent to the area of bone loss, the defect is filled with demineralized freeze-dried bone allograft mixed with enamel matrix derivative. The use of the videoscope allows this procedure to be performed using very small incisions. The case presented shows improved clinical and radiographic outcomes. CONCLUSION: The method described here allows visualization of implant surfaces and the surrounding tissues, which may improve clinical and radiographic outcomes.

The role of bacterial biofilm and mechanical forces in modulating dental implant failures.

Currently many assume that bacteria are the primary etiological factor associated with failure of titanium dental implants. However, emerging data indicates a possible role for mechanical forces in implant failure. This study is based on the hypothesis that the synergistic effect of mechanical forces and bacterial biofilm can lead to surface damage resulting in in vivo release of metallic particles. The primary aim of the study was to develop a dynamic fatigue test method for dental implants immersed in wet environments such as; (i) 0.01 M phosphate buffer saline (PBS); (ii) lactic acid (pH = 5); (iii) bacterial polyculture. Four dental implants each were subjected to fatigue loading from 45 N to 450 N at 4 Hz for 2 million cycles while immersed in (i) PBS (negative control); (ii) bacterial culture (test); and (iii) lactic acid (positive control). Post-testing, optical microscopy, x-ray photoelectron spectroscopy, and electrochemical corrosion tests were performed to evaluate the surface morphology, chemistry, and potential, respectively, of titanium implants. Post-testing, surface discoloration was evident in all three groups. However, the surface damage was further established in XPS analyses of test specimens, which showed that the interplay of bacterial biofilm and mechanical forces resulted in thinning of the TiO2. Lower corrosion potential (Ecorr) of the test specimens compared to positive and negative controls also illustrated damage to the oxide layer. However, other electrochemical parameters such as linear polarization resistance (LPR) and corrosion rate (CR) were comparable among the groups indicating the corrosion resistance post-testing. The synergistic effect of cyclic occlusal loading and bacteria biofilm could negatively affect the surface of titanium dental implants.

Titanium particles generated during ultrasonic scaling of implants.

BACKGROUND: There is growing concern that titanium particles may play a role in peri-implant breakdown. Ultrasonic scalers are routinely used in the debridement of peri-implant lesions. This in vitro study is designed to evaluate if titanium particles are produced when an ultrasonic scaler is used on an implant. METHODS: New sandblasted, large grit, acid etched (SLA) coated implants were subjected to ultrasonic scaling with stainless steel, titanium, and PEEK plastic tips. The implants were placed in a holding device and the ultrasonic scaler was positioned on the SLA surface under 25 grams of pressure. The implants were subjected to 30 scaling motions. The ultrasonic coolant water was collected and the number of metallic particles were counted under a light microscope. The particles were confirmed to be titanium via elemental analysis. The implants were visually evaluated for damage to the SLA coating. RESULTS: No metallic particles were detected in the water supplied to the ultrasonic scalers (passive control). Metallic particles were detected when implants were subjected to the ultrasonic coolant water only without the scaler tip touching the implant (active control). All implants that were scaled produced metallic particles and showed easily detectable damage to the SLA layer. CONCLUSIONS: All ultrasonic scaling caused the production of titanium particles and caused damage to the SLA coating of the implant. Ultrasonic scalers should be used with great caution in the treatment of peri-implant conditions and care should be taken to not touch the SLA surface of the implant.

Evaluation of oral microbial corrosion on the surface degradation of dental implant materials.

BACKGROUND: Titanium (Ti) dominates as the material of choice for dental implant systems. Recently, titanium-zirconium alloy (TiZr) and zirconia (ZrO2 ) have emerged as alternative materials due to higher mechanical strength and lower corrosion susceptibility. Oral pathogenic bacteria can colonize Ti surfaces, leading to surface degradation, which has yet to be investigated on TiZr and ZrO2 . The aim of this study was to compare in vitro oral bacterial adhesion and subsequent surface degradation on commercial Ti, TiZr, and ZrO2 implants. METHODS: Ti, TiZr, and ZrO2 implants with sandblasted, acid-etched (SLA) surfaces in addition to modified SLA-treated (modSLA) Ti implants (n = 3) were immersed for 30 consecutive days in Streptococcus polyculture. Post-immersion, adherent bacterial count was quantified. Optical microscopy was used to assess qualitative degradation and score Ti-based implants based on degree of surface damage while electrochemical testing quantified corrosion behavior. Analysis of variance followed by post-hoc Tukey test was used to statistically compare quantitative results (α = 0.05). RESULTS: Ti-SLA, Ti-modSLA, and TiZr-SLA implants exhibited localized features characteristic of corrosion attack while ZrO2 -SLA implants experienced minimal changes in surface morphology as compared to non-immersed control. Corrosion features were more numerous on Ti-modSLA implants but smaller in size as compared with those on Ti-SLA and TiZr-SLA implants. No significant differences in corrosion resistance (polarization resistance and corrosion rate) were observed between Ti-SLA, Ti-modSLA, and TiZr-SLA implants. CONCLUSION: TiZr and ZrO2 dental implant surfaces were not more susceptible to colonization and surface degradation by oral Streptococcus species than commercially pure Ti implants.

Absence of histologic signs of chronic inflammation following closed subgingival scaling and root planing using the dental endoscope: human biopsies - a pilot study.

BACKGROUND: The primary goal of periodontal therapy is the reduction or elimination of inflammation. Traditionally, this is accomplished through removal of subgingival tooth-borne accretions using non-surgical and/or surgical treatment modalities. Numerous studies indicated the difficulty in removing these accretions to the point that histologic manifestations of chronic inflammation are eliminated. A companion to the current study demonstrated that subgingival inflammation was associated most often with calculus covered with biofilm, not biofilm alone. This pilot study evaluated the histologic response in humans to removal of calculus and biofilm with the aid of the dental endoscope. METHODS: Twelve teeth in six patients were identified as test teeth, and all subgingival deposits visible with the endoscope were removed in a single treatment by an operator experienced in root planing and the use of the dental endoscope. The 12 teeth and the coronal portion of their periodontal attachment apparatus were removed 6 months after a single episode of closed subgingival scaling and root planing. Biopsies were processed for histologic evaluation. RESULTS: There were no histologic signs of chronic inflammation. Deposits of calculus and biofilm were seen on one section of one tooth but apparently were deposited after initial therapy. Bone repair and the growth of a long junctional epithelium were observed on previously diseased root surfaces. CONCLUSION: Histologic signs of chronic inflammation were absent 6 months after a single course of closed subgingival scaling and root planing using the dental endoscope.

The relationship between the presence of tooth-borne subgingival deposits and inflammation found with a dental endoscope.

BACKGROUND: Inflammatory periodontal diseases are found in many dentate individuals, but therapists and researchers who assess disease activity have had to rely on external clinical signs and symptoms to ascertain the health of the subgingival periodontal tissues. However, by using an endoscope in the subgingival environment, the therapist can see the relationship of subgingival tooth-borne accretions to signs of inflammation in the pocket wall. This study explored those relationships via the endoscope. METHODS: Twenty-six patients with moderate to severe periodontitis were chosen. The study visit involved a standardized, masked examiner who gathered data on the external gingival index, probing depth, gingival recession, and clinical attachment level. A second standardized examiner, masked to the findings of the first, used a dental endoscope. A set of indices (endoscopic biofilm index, endoscopic calculus index, and endoscopic gingival index) specifically developed for subgingival parameters was used. A fixation stent ensured that the periodontal probe and the endoscopic explorer traveled along the same path. RESULTS: A statistically significant relationship was found between deposits of subgingival calculus covered with biofilm and inflammation of the pocket wall, as measured by color change. In >60% of the cases, this inflammation was associated only with biofilm over deposits of calculus, not biofilm alone. Only subgingival calculus was statistically significant in relation to the positive traditional gingival index. CONCLUSIONS: Deposits of subgingival calculus covered with biofilm were directly related to >60% of pocket wall inflammation as measured by increased redness of the pocket epithelium. This was in comparison to biofilm alone.

The influence of non-matching implant and abutment diameters on radiographic crestal bone levels in dogs.

BACKGROUND: It has been shown that different implant designs and different vertical implant positions have an influence on crestal bone levels. The aim of the present study was to evaluate radiographic crestal bone changes around experimental dental implants with non-matching implant-abutment diameters placed submucosally or transmucosally at three different levels relative to the alveolar crest. METHODS: Sixty two-piece dental implants with non-matching implant-abutment diameters were placed in edentulous spaces bilaterally in five foxhounds. The implants were placed submucosally or transmucosally in the left or the right side of the mandible. Within each side, six implants were randomly placed at three distinct levels relative to the alveolar crest. After 12 weeks, 60 crowns were cemented. Radiographs were obtained from all implant sites following implant placement, after crown insertion, and monthly for 6 months after loading. RESULTS: Radiographic analysis revealed very little bone loss and a slight increase in bone level for implants placed at the level of the crest or 1 mm above. The greatest bone loss occurred at implants placed 1 mm below the bone crest. No clinically significant differences regarding marginal bone loss and the level of the bone-to-implant contact were detected between implants with a submucosal or a transmucosal healing. CONCLUSIONS: Implants with non-matching implant-abutment diameters demonstrated some bone loss; however, it was a small amount. There was no clinically significant difference between submucosal and transmucosal approaches.

Surface characterization of titanium implant healing abutments before and after placement.

BACKGROUND: Implant healing abutments (IHA) have a vital role in soft tissue healing after implant placement. Although there is thorough investigation on the implant surface, little is known about the effects potentially damaging oral conditions impose on healing abutments. PURPOSE: To characterize the surface of titanium healing abutments before and after clinical placement to understand the effects of the oral environment and time on the device surface. MATERIALS AND METHODS: Ten regular Straumann IHA were subjected to characterization pre and postplacement to elucidate the effects of the oral environment on device surfaces. Changes in surface crystallinity, morphology, and elemental composition were monitored with Raman spectroscopy, scanning electron microscopy, optical microscopy, and x-ray photoelectron spectroscopy, respectively. In addition, corrosion rate and polarization resistance were obtained to assess electrochemical device stability after placement. RESULTS: Control analysis indicated the titanium oxide of IHAs was thicker than natural commercially pure titanium and had the structure of crystalline anatase. After removal, the abutments possessed large amounts of biological debris, visible scratches, and discoloration sparsely on the surface. Spectroscopic analysis revealed the titanium oxide on the surface of IHAs was structurally unchanged, with crystalline titanium dioxide still present on the surface. Electrochemical results revealed that implanted healing abutments possessed a significantly higher corrosion rate than controls (change in corrosion rate = 2.34 ± 0.58 nm/year). CONCLUSIONS: Healing abutments were stable in the oral environment due to the chemical stability of the oxide, and were likely subjected to abrasions from unintentional loading and oral hygiene techniques.