Complications and treatment errors in implant positioning in the aesthetic zone: Diagnosis and possible solutions.

Incorrect implant positioning can lead to functional and aesthetic compromise. Implant positioning errors can occur in three dimensions: mesiodistal, corono-apical, and orofacial. Treatment solutions to manage adverse outcomes through positioning errors require an understanding of the underlying conditions and of those factors that may have led to the error being committed in the first place. These types of complications usually occur because of human factors. If errors do occur with adverse aesthetic outcomes, they are difficult and sometimes impossible to correct. Connective tissue grafts to reverse recession defects are only feasible in defined situations. The option to remove and replace the implant may be the only recourse, provided the removal process does not further compromise the site. Error in judgment by the clinician.

Prevention and Management of Cheek and/or Tongue Biting Related to Posterior Implant-Supported Fixed Dental Prostheses (ISFDPs).

After the loss of several adjacent posterior teeth, bone resorption occurs that can lead to a marked occlusal discrepancy between arches. This discrepancy may originate from the more pronounced resorption at the facial portion of the alveolar bone crest, often resulting in a more palatal implant position. Therefore, establishing normal overbite and cusp-fossa relation may become difficult, namely causing inappropriate crown contours and emergence profiles. This manuscript describes a technique in which a different occlusal configuration is given to solve some problems that edge-to-edge occlusal configuration produces. For instance, patients may suffer from cheek and/or tongue biting after the delivery of a maxillary posterior implant-supported fixed dental prosthesis resulting in an edge-to-edge occlusal configuration. In instances of severe maxillary resorption in the posterior buccal zone, it is recommended to consider a distinct cross-bite occlusion and by this prevent the well-known discomfort and clinical signs associated with both an edge-to-edge interarch relationship or a so-called "stretched" transversal overbite.

A modified technique for the intraoral assessment of static occlusal contacts.

This article describes a procedure in which articulating paper is modified for the intraoral assessment of static occlusal contacts. The rectangular-shaped articulating paper is modified by creating parallel cuts at 2- to 3-mm intervals perpendicular to its long side without completely separating the paper. This modification may improve the accuracy in determining occlusal contacts and therefore facilitate an occlusal adjustment procedure.

Implant placement post extraction in esthetic single tooth sites: when immediate, when early, when late?

Implant placement in post-extraction sites of single teeth in the esthetic zone has been a topic of great interest in the field of implant dentistry since 1990. Triggered by the development of guided bone regeneration, the concept of immediate implant placement became quite popular in the 1990s. In the past 12 years, however, the dental community has begun to focus increasingly on the esthetic outcomes of post-extraction implant placement and several studies indicated a significant risk for the development of mucosal recessions with immediate implants. Parallel with this, significant progress has been made in the understanding of tissue biology in terms of hard and soft tissue alterations post extraction, based on preclinical, clinical and radiological studies. This knowledge has helped better to understand the etiology of these esthetic complications with immediate implant placement. The present review first analyzes the various phases of the development of therapeutic strategies over the years for post-extraction implant placement in single tooth sites in the esthetic zone. It presents the current knowledge concerning the terminology with immediate, early and late implant placement, the risk factors for the development of esthetic complications, and the selection criteria for the various treatment options. In the second part, clinical recommendations are given, since a clinician active in this field of implant therapy can use all treatment options depending on the preoperative analysis including a 3D cone beam computed tomography. The selection criteria for all four treatment options are presented and documented with typical case reports to illustrate the current treatment approaches applied in daily practice.

Four-unit fixed dental prostheses replacing the maxillary incisors supported by two narrow-diameter implants - a five-year case series.

OBJECTIVES: (1) To determine the survival rate of 10 four-unit fixed dental prostheses (FDPs) replacing the four maxillary incisors, supported by 20 narrow-diameter implants (NDIs), (2) to assess the incidence of mechanical and biological complications, and (3) to evaluate bone level changes longitudinally after final FDP insertion. MATERIALS AND METHODS: Ten patients (six women, four men), mean age 49.4 ± 12.6 years, were treated with a four-unit anterior maxillary FDP (six screw-retained; four cemented). Biological parameters, eventual technical complications, radiographic measurements, and study casts were assessed at 1 (baseline), 3, and 5 years after implant placement. A multilevel logistic regression test was performed on clinical parameters and bone level changes (significance level P < 0.05). RESULTS: The 5-year implant and FDP survival rate was 100%. Mean modified plaque index (mPI) values were 0.03 and 0.02 at 3 and 5 years, significantly lower when compared to mPI (0.11 ± 0.31) at 1 year. Mean modified sulcus bleeding index (mSBI) was 0.08, 0.08, and 0.15 over time. Probing depth (PD) values were 1.57, 1.64, and 2.03 mm. Statistically significant differences were found between 1 vs. 5 year (P = 0.0003) and 3 vs. 5 year (P = 0.001). Keratinized mucosa (3.65 mm) remained stable during observation period. DIB mean values were 2.01 ± 0.34, 2.13 ± 0.13, and 2.17 ± 0.38 mm. Patient satisfaction based on visual analog scale revealed favorable fulfillment of overall treatment and esthetic expectations. CONCLUSIONS: Two NDIs supporting a four-unit FDP to replace the four missing maxillary incisors may be considered a predictable treatment modality.

Influence of simulated bone-implant contact and implant diameter on secondary stability: a resonance frequency in vitro study.

OBJECTIVES: This study tested the hypothesis of no differences in resonance frequency for standardized amounts of simulated bone-implant contact around implants with different diameters. In addition, it was evaluated if resonance frequency is able to detect a difference between stable and rotation mobile ("spinning") implants. MATERIAL AND METHODS: Implants with diameters of 3.3, 4.1 and 4.8 mm were placed in a purposely designed metal mould where liquid polyurethane resin was then poured to obtain a simulated bone-implant specimen. By regulating the mould, it was possible to create the following simulated bone-implant contact groups: 3.3 mm (198.6 mm(2)); 4.1 mm (198.8 mm(2)); 4.8 mm (200.2 mm(2)); 4.8 mm (231.7 mm(2)); 4.8 mm (294.7 mm(2)). Each group included 10 specimens. After resin setting, resonance frequency was measured. On the last group, measurements were repeated after establishing implant rotational mobility. One-way ANOVA tests with post hoc comparisons, a Pearson's correlation coefficient and a t-test for repeated measurements were used to evaluate statistically significant differences. RESULTS: Implants with different diameters but with the same amount of simulated osseointegration revealed no differences in resonance frequency. On the contrary, an increase of simulated bone-implant contact resulted in significantly higher resonance frequency. A clear direct linear correlation resulted between resonance frequency and simulated bone-implant contact. Furthermore, a significant difference resulted between resonance frequency measured before and after creation of rotational mobility. CONCLUSIONS: Within the conditions of this study, the secondary stability was correlated with the simulated bone-implant contact. In addition, resonance frequency was able to discern between stable and rotation mobile implants.

Effects of in vitro cyclic dislodging on retentive force and removal torque of three overdenture attachment systems.

BACKGROUND: Mandibular two-implant-retained overdentures were suggested as first choice of treatment for edentulous mandibles. However, wear of the attachments may reduce their retention and compromise long-term clinical success. AIM: The aim of this in vitro study was to compare the change in the retentive force and removal torque of three attachment systems during simulation of insertion-removal cycles. MATERIALS AND METHODS: Thirty custom-manufactured polyvinyl chloride blocks mimicking an implant-retained overdenture using Locator(®) -, spherical Dalbo(®) -PLUS - and SFI(®) -Bar-attachments on Straumann(®) RN Implants were fabricated. The samples were distributed equally into three groups which were subdivided into two sets of five blocks, one set with implants parallel to one another and the other with angulated implants (12°). All attachments were tightened to 35Ncm, while the fixation screws of the SFI(®) -Bar were tightened to 15Ncm. Testing was carried out with an Instron(®) universal testing machine for a total of 14,600 insertion-removal cycles in 0.9% sodium chloride solution. Retentive forces from cycles 10, 100, 1000, 5000, 10,000 and 14,600 were used for the analysis. The removal torque of the attachments was measured before and at the end of the study. Statistical analysis comprised three-way ANOVA and multiple linear regression models. RESULTS: Initially, all three attachment systems demonstrated increasing retentive forces. From cycle 5000 on, Locator(®) -attachments showed lower mean retentive forces than the Dalbo(®) -PLUS and SFI(®) -Bar-groups. The Dalbo(®) -PLUS and SFI(®) -Bar-attachments showed a steady yet not significant increase during the whole observation period. Implant-angulation had no significant influence on the retention forces. The final mean removal torques were significantly reduced. No complete failure was observed. CONCLUSIONS AND CLINICAL IMPLICATIONS: Within the limits of this in vitro study, it can be concluded that the investigated overdenture attachment systems are sufficiently resistant to wear. However, the Dalbo(®) -Plus- and SFI(®) -Bar- exhibit higher retentive capacities than the Locator(®) -attachment over time. The fixation screw of the SFI(®) -Bar may loosen during long-term use, but these observations might be less important if 1-year recall intervals are respected. An angulation of up to 12° between implants does not seem to have a significant effect on attachment wear.

Survival rates of short (6 mm) micro-rough surface implants: a review of literature and meta-analysis.

OBJECTIVE: The aim of this review was to test the hypothesis that 6 mm micro-rough short Straumann(®) implants provide predictable survival rates and verify that most failures occurring are early failures. MATERIALS AND METHODS: A PubMed and hand search was performed to identify studies involving micro-rough 6-mm-short implants published between January 1987 and August 2011. Studies were included that (i) involve Straumann(®) 6 mm implants placed in the human jaws, (ii) provide data on the survival rate, (iii) mention the time of failure, and (iv) report a minimum follow-up period of 12 months following placement. A meta-analysis was performed on the extracted data. RESULTS: From a total of 842 publications that were screened, 12 methodologically sound articles qualified to be included for the statistical evaluation based on our inclusion criteria. A total of 690 Straumann(®) 6-mm-short implants were evaluated in the reviewed studies (Total: placed-690, failed-25; maxilla: placed-266, failed-14; mandible: placed-364, failed-5; follow-up period: 1-8 years). A meta-analysis was performed on the calculated early cumulative survival rates (CSR%). The pooled early CSR% calculated in this meta-analysis was 93.7%, whereas the overall survival rates in the maxilla and mandible were 94.7% and 98.6% respectively. Implant failures observed were predominantly early failures (76%). CONCLUSION: This meta-analysis provides robust evidence that micro-rough 6-mm-short dental implants are a predictable treatment option, providing favorable survival rates. The failures encountered with 6-mm-short implants were predominantly early and their survival in the mandible was slightly superior.

Non-invasive assessment of peri-implant mucosal thickness: A cross-sectional study.

BACKGROUND: This study aimed to evaluate the reliability and reproducibility of different non-invasive methods for the assessment of peri-implant mucosal thickness. METHODS: Subjects with two adjacent dental implants in the central maxillary region were included in this study. Three different methods to assess facial mucosal thickness (FMT) were compared: digital file superimposition using Digital Imaging and Communication in Medicine (DICOM) and stereolithography (STL) files of the arch of interest (DICOM-STL), DICOM files alone, and non-ionizing ultrasound (US). Inter-rater reliability agreements between different assessment methods were analyzed using inter-class correlation coefficients (ICCs). RESULTS: A total of 50 subjects with 100 bone-level implants constituted the study population. Assessment of FMT using STL and DICOM files demonstrated excellent inter-rater reliability agreement. Mean ICC values of 0.97 and 0.95 were observed in the DICOM-STL and DICOM groups, respectively. Comparison between the DICOM-STL and US revealed good agreement, with an ICC of 0.82 (95% CI: 0.74 to 0.88) and a mean difference of -0.13 ± 0.50 mm (-1.13 to 0.86). Comparison between DICOM files alone versus US showed good agreement, with an ICC of 0.81 (95% CI: 0.73 to 0.89) and a mean difference of -0.23 ± 0.46 mm (-1.12 to 0.67). Comparison between DICOM-STL and DICOM files revealed excellent agreement, with an ICC of 0.94 (95% CI: 0.91 to 0.96) and a mean difference of 0.1 ± 0.29 mm (LOA -0.47 to 0.46). CONCLUSIONS: Quantification of peri-implant mucosal thickness via analysis of DICOM-STL files, DICOM files, or US assessment are comparably reliable and reproducible methods.

Dimensional changes of peri-implant soft tissue over 2 years with single-implant crowns in the anterior maxilla.

OBJECTIVE: To compare the peri-implant soft tissue dimensions after insertion of single-implant crowns in the anterior maxilla. MATERIALS AND METHODS: Twenty patients were accepted according to well-defined inclusion criteria and randomized to porcelain-fused-to-metal (PFM) or all-ceramic groups. Follow-up was at: Baseline (B), Crown Insertion (CI), 1-year (1Y), and 2-year (2Y). The following parameters were statistically analysed: distance implant shoulder to marginal peri-implant mucosa (DIM), papilla height (PH), width of keratinized mucosa (KM), crestal bone level (CBL), full mouth plaque score (FMPS), full mouth bleeding score (FMBS), and probing pocket depth. RESULTS: Between groups measurements for DIM, PH, KM, CBL, FMPS, and FMBS showed no statistically significant differences except the distal CBLs to adjacent tooth. DIM (mid-facial) decreased from B to CI remaining stable at 1Y and 2Y (p-value 0.0014). DIM mesial and distal aspects significantly increased from B to CI showing signs of stability at the 2Y. PH between B and CI increased at the mesial site and at the distal site, thereafter, peri-implant soft tissues were stable at the 2Y. CONCLUSION: The insertion of an implant crown affects the peri-implant mucosa morphology by an apical displacement at the mid-facial aspect and coronal at mesial and distal sites.

Esthetic outcomes with porcelain-fused-to-ceramic and all-ceramic single-implant crowns: a randomized clinical trial.

OBJECTIVES: the aim of this randomized-controlled clinical trial was to compare the objective and subjective esthetic outcomes of two types of screwed-retained single-implant crowns. MATERIALS AND METHODS: participants were randomly assigned to the test (all-ceramic) and control [porcelain-fused-to-ceramic (PFM)] groups and were seen under investigation at baseline (B), crown insertion (CI), 1-year follow-up (1Y), and 2-year follow-up (2Y). Objective parameters were assessed by an intra-oral digital photograph (1:1 ratio), a study cast, a standardized radiograph, periodontal/peri-implant measurements, and questionnaires were obtained for the subjective parameters. In addition, pink esthetic score (PES) and white esthetic score (WES) were calculated for both groups. For the subjective evaluation, a visual analogue scale (VAS) questionnaire was used to assess the level of patient satisfaction regarding the esthetic outcome. Then, nine expert clinicians visually inspected and assessed subjective evaluation at the professional level. Statistical analysis was used to compare between groups and investigational appointments. RESULTS: twenty patients were included in the study, 10 allocated to the all-ceramic group and 10 to the PFM group. No statistically significant differences were observed for the objective measurements comparing the test and control groups. Minor chipping of the ceramic veneering material was observed in the two patients of control group. The mean difference for all groups comparing objective parameters revealed an increase of papilla height between time points. A slight recession (0.26 mm) of the peri-implant mucosal margin at the implant site was observed between 1Y and 2Y. Mean values for PES and WES were 13.9 and 13.1 for the PFM group and for the all-ceramic group, respectively. These values were not statistically significant. Implant crown volume, outline, translucency, and characterization showed major discrepancies with the contra-lateral natural teeth. As for subjective parameters, VAS patients' responses regarding their perceptions of the esthetic outcome showed no statistical differences between groups and clinicians' accuracy scores were 50% and 47% for PFM and all-ceramic crowns, respectively. CONCLUSION: PFM and all-ceramic single-implant restorations may be indistinguishable from each other regarding the objective/subjective assessment of esthetic integration. The material chosen for fabricating an implant crown per se does not ensure an optimal esthetic outcome if other esthetic parameters are not present.

Three-dimensional morphometry of strained bovine periodontal ligament using synchrotron radiation-based tomography.

The periodontal ligament (PDL) is a highly vascularized soft connective tissue. Previous studies suggest that the viscous component of the mechanical response may be explained by the deformation-induced collapse and expansion of internal voids (i.e. chiefly blood vessels) interacting with liquids (i.e. blood and interstitial fluids) flowing through the pores. In the present work we propose a methodology by means of which the morphology of the PDL vascular plexus can be monitored at different levels of compressive and tensile strains. To this end, 4-mm-diameter cylindrical specimens, comprising layers of bone, PDL and dentin covered by cementum, were strained at stretch ratios ranging from lambda = 0.6 to lambda = 1.4 and scanned using synchrotron radiation-based computer tomography. It was concluded that: (1) the PDL vascular network is layered in two distinct planes of blood vessels (BVs): an inner layer (close to the tooth), in which the BVs run in apico-coronal direction, and an outer layer (close to the alveolar bone), in which the BVs distribution is more diffuse; (2) during tension and compression, the porosity tissue is kept fairly constant; (3) mechanical straining induces important changes in BV diameters, possibly modifying the permeability of the PDL and thus contributing to the viscous component of the viscoelastic response observed under compressive forces.

Load response of periodontal ligament: assessment of fluid flow, compressibility, and effect of pore pressure.

The periodontal ligament (PDL) functions both in tension and in compression. The presence of an extensive vascular network inside the tissue suggests a significant contribution of the fluid phase to the mechanical response. This study examined the load response of bovine PDL under different pore pressure levels. A custom-made pressure chamber was constructed. Rod-shaped specimens comprising portions of dentine, bone, and intervening layer of PDL were extracted from bovine mandibular molars. The dentine ends of the specimens were secured to the actuator while the bone ends were affixed to the load cell. The entire assemblage was surrounded by the pressure chamber, which was then filled with saline. Specimens loaded at 1.0 Hz sinusoidal displacement were subjected to four different environmental fluid pressures (i.e., pressures of 0.0-1.0 MPa). The video images recorded during the tests were analyzed to determine whether or not fluid exchange between the PDL and the surrounding medium took place during mechanical loading. A value for the tissue's apparent Poisson ratio was also determined. The following observations were made: (1) fluid was squeezed out and pumped into the ligament during the compressive and tensile loading phases, (2) the PDL was highly compressible, and (3) the pore pressure had no influence on the mechanical response of the PDL. The present tests emphasized the biphasic structure of PDL tissue, which should be considered as a porous solid matrix through which fluid can freely flow.

The use of polytetrafluoroethylene tape for the management of screw access channels in implant-supported prostheses.

This article describes a procedure in which polytetrafluoroethylene (PTFE) tape is used to seal the screw access channel to protect the screw head of the abutment and crown screw in implant-supported restorations. The material can be sterilized, is easy to manipulate, radiopaque, and less associated with malodor when retrieved. Malodor is primarily associated with the implant-abutment interface configuration and the suprastructure component design of a given implant system. This technique enables fast removal of the filling material in a single piece, preventing unpredictable and time-consuming manipulations when removal of the screw-retained crown or abutment is required.

Outcome evaluation of early placed maxillary anterior single-tooth implants using objective esthetic criteria: a cross-sectional, retrospective study in 45 patients with a 2- to 4-year follow-up using pink and white esthetic scores.

BACKGROUND: To validate the concept of early implant placement for use in the esthetically sensitive anterior maxilla, clinical trials should ideally include objective esthetic criteria when assessing outcome parameters. METHODS: In this cross-sectional, retrospective 2- to 4-year study involving 45 patients treated with maxillary anterior single-tooth implants according to the concept of early implant placement, a novel comprehensive index, comprising pink esthetic score and white esthetic score (PES/WES; the highest possible combined score is 20), was applied for the objective esthetic outcome assessment of anterior single-tooth implants. RESULTS: All 45 anterior maxillary single-tooth implants fulfilled strict success criteria for dental implants with regard to osseointegration, including the absence of peri-implant radiolucency, implant mobility, suppuration, and pain. The mean total PES/WES was 14.7 +/- 1.18 (range: 11 to 18). The mean total PES of 7.8 +/- 0.88 (range: 6 to 9) documents favorable overall peri-implant soft tissue conditions. The two PES variables facial mucosa curvature (1.9 +/- 0.29) and facial mucosa level (1.8 +/- 0.42) had the highest mean values, whereas the combination variable root convexity/soft tissue color and texture (1.2 +/- 0.53) proved to be the most difficult to fully satisfy. Mean scores were 1.6 +/- 0.5 for the mesial papilla and 1.3 +/- 0.5 for the distal papilla. A mean value of 6.9 +/- 1.47 (range: 4 to 10) was calculated for WES. CONCLUSIONS: This study demonstrated that anterior maxillary single-tooth replacement, according to the concept of early implant placement, is a successful and predictable treatment modality, in general, and from an esthetic point of view, in particular. The suitability of the PES/WES index for the objective outcome assessment of the esthetic dimension of anterior single-tooth implants was confirmed. However, prospective clinical trials are needed to further validate and refine this index.

Early implant placement with simultaneous guided bone regeneration following single-tooth extraction in the esthetic zone: 12-month results of a prospective study with 20 consecutive patients.

BACKGROUND: Early implant placement is one of the treatment options in postextraction sites in the anterior maxilla. Implant placement is performed after a soft tissue healing period of 4 to 8 weeks. Implant placement is combined with a simultaneous guided bone regeneration (GBR) procedure to rebuild esthetic facial hard and soft tissue contours. METHODS: In this prospective case-series study, 20 consecutive patients treated with an implant-borne single crown were prospectively followed for 12 months. Clinical, radiologic, and esthetic parameters were recorded to assess treatment outcomes. RESULTS: At the 12-month examination, all 20 implants were successfully integrated, demonstrating ankylotic stability and healthy peri-implant soft tissues as documented by standard parameters. The esthetic outcomes assessed by a pink esthetic score (PES) and a white esthetic score (WES) demonstrated pleasing results overall. The WES values were slightly superior to the PES values. The periapical radiographs showed minimal crestal bone loss around the used bone level implants, with mean bone loss of 0.18 mm at 12 months. Only one implant showed >0.5 mm bone loss, combined with minor mucosal recession of 0.5 to 1.0 mm. CONCLUSIONS: This prospective case series study evaluating the concept of early implant placement demonstrated successful tissue integration for all 20 implants. The short-term follow-up of 12 months revealed pleasing esthetic outcomes overall, as assessed by objective parameters. The risk for mucosal recession was low; only one patient showed minor recession of the facial mucosa. These encouraging results need to be confirmed with 3- and 5-year follow-up examinations.

Descriptive analysis of implant and prosthodontic survival rates with fixed implant-supported rehabilitations in the edentulous maxilla.

BACKGROUND: This descriptive study reviewed the 1- to 15-year survival rates of fixed implant rehabilitations in the edentulous maxilla. METHODS: An electronic search was conducted, and cohort studies with 1- to 15-year follow-ups were identified by two independent reviewers. The implant and prosthodontic survival rates were reviewed at 1-, 3-, 5-, 10-, and 15-year endpoints. Descriptive analysis includes surface characteristics, bone-augmentation procedure, prosthetic design, and implant number and distribution along the edentulous maxilla. RESULTS: Thirty-three studies, including 1,320 patients and 8,376 implants, were selected for analysis. The overall calculated implant survival rates ranged from 94% (1 year) to 87.7% (15 years). The implant survival rates for rough-surface implants ranged from 97% (1 year) to 98% (15 years); machined implants showed survival rates of 92% to 87.7%; respectively. Implants placed in native bone had greater survival rates than those placed in augmented bone. The prosthodontic survival rate ranged from 98.2% at 1 year to 92.1% at the 10-year endpoint, and it was only influenced by the implant number and distribution. CONCLUSIONS: Implants with rough surfaces showed a statistically higher survival rate than machined implants at all intervals. Implants placed in augmented bone had a statistically lower survival rate, except for rough-surface implants, for which no statistical difference between augmented and non-augmented bone survival rates was found. Machined implants showed a stable survival rate only when placed in native bone. When machined implants were placed in augmented bone, the survival rate decreased significantly at each study endpoint. The prosthetic design, veneering material, and the number of prostheses per arch had no influence on the prosthodontic survival rate. Implant number and distribution along the edentulous maxilla seemed to influence the prosthodontic survival rate.

Implant loading protocols for the partially edentulous esthetic zone.

PURPOSE: The scientific evidence related to different or novel implant loading (primary objective) and directly associated implant placement (secondary objective) protocols developed for the anterior maxillae of partially edentulous patients was reviewed. MATERIALS AND METHODS: A comprehensive search of electronic databases and a hand search of six relevant journals was performed. The principal outcome variables were implant survival, implant success, and esthetic appearance. Concerning esthetic treatment outcomes, articles were specifically screened for the presence of objective evaluation parameters and patient satisfaction assessment. RESULTS: The analysis of the literature on immediately restored or conventionally loaded implants in the esthetic zone revealed an initial survival rate of 97.3% after 1 year (10 prospective cohort studies and one case series). For periods of 1 to 5 years, the survival rate was 96.7%. These survival rates are consistent with previous reports on more traditional loading modalities. However, for immediately placed implants with immediate restoration and occlusal loading, the survival rate dropped by approximately 10% (four studies). Success criteria such as stable crestal bone levels, soft tissue recession, and probing depth could not be evaluated on the basis of the available literature. CONCLUSION: There is a paucity of prospective cohort studies addressing patient-centered outcomes. No parameters specific to immediate loading protocols were available for evaluation. In order to validate or reject such implant protocols for use in the esthetically sensitive anterior maxilla, long-term clinical trials should routinely include objective esthetic criteria that comprehensively embrace the pertinent elements of "pink and white esthetics" in the form of readily used indices.

The effect of water storage, elapsed time and contaminants on the bond strength and interfacial polymerization of a nanohybrid composite.

PURPOSE: To systematically characterize the effect of time lapse, water storage, and selected contaminants on the bond strength of a nanofilled dental composite. MATERIALS AND METHODS: Half-dumbbell-shaped samples were fabricated out of light-polymerizing composite resin. To function as substrates they were aged for 30 days in water. Prior to bonding, the substrates' surfaces were subjected to the following treatments: 1) Removing a 0.2- to 0.4-mm layer using a fluted carbide bur; 2) grit blasting with 50 microm alumina particles; 3) etching with phosphoric acid gel; 4) grit blasting followed by etching; 5) blasting with tribochemical particles followed by silane application; 6) sanding with 400-grit paper, air aging of the adherent half-sample before bonding; 7) surface contamination with saliva; 8) surface contamination with blood. In each group (n = 30), freshly polymerized (except in group 6) adherent half-samples were bonded to the substrate half-samples by a layer of unfilled adhesive resin. Fifteen full dumbbell-shaped specimens were subjected to tensile testing after 1 h and 15 after 7 days water storage. In a positive control group, freshly cured half-samples were bonded shortly after fabrication. The tensile strength was analyzed using Weibull statistics and presented in terms of the material's characteristic strength and shape parameter. Fractographs of the two weakest and strongest samples of each group were produced. The surfaces were searched to locate hackle, wake hackle and the origin of the fracture. RESULTS: Surface roughness and time lapse increased the bond strength of the repaired specimens. All groups in which surface roughness was produced before bonding increased in repair strength. Post-bonding aging improved strength. Fractographs yielded interpretable data whenever larger surfaces of single phase bonding resin were present. CONCLUSION: 1) Roughening and etching an aged composite's surface prior to applying a coat of unfilled resin and the filled material increases repair bond strength by up to 100%. 2) The repair bond strength of a roughened aged composite is 25% to 30% inferior to the tensile strength of solid specimens. 3) After 7 days' storage in water, no detrimental effect could be seen from saliva or blood contamination if the surfaces were properly rinsed.