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.

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.

The Management of Peri-implant Mucosa Deficiencies in Esthetic Sites: Case Report of a Combined Surgical-Prosthetic Approach.

In cases of single missing teeth, implant rehabilitation is generally the preferred treatment option. However, obtaining pleasing esthetic results in the anterior maxillary region and maintaining or rebuilding peri-implant papillae remain challenging tasks. The loss of papillae may cause not just functional but also phonetic and esthetic problems. There is scarce information on the reliability of surgical approaches concerning the peri-implant papilla. The purpose of this case report is to present a modified prosthetic-surgical technique to enhance the convex facial contour of the peri-implant mucosa and volume and height of papillary tissue in an esthetically highly demanding patient.

An In Vitro Evaluation of the Loosening of Different Interchangeable Abutments in Internal-Connection-Type Implants.

PURPOSE: The aim of this study was to compare the loosening of interchangeable one-piece abutments connected to internal-connection-type implants after cyclic loading. MATERIALS AND METHODS: Four implant abutment groups (n = 7 in each group) with Straumann tissue-level implants were assessed: Straumann solid abutment (group S), Southern Implants solid abutment (group SI), Implant Direct straight abutment (group ID), and Blue Sky Bio regular platform abutment (group BSB). The implant was firmly held in a special jig to ensure fixation. Abutment screws were tightened to manufacturers' recommended torque with a digital torque gauge. The hemispherical loading members were fabricated for the load cell of a universal testing machine to evenly distribute the force on the specimens and to fulfill the ISO 14801:2007 standard. A cyclic loading of 25 N at 30 degrees to the implant's long axis was applied for a duty of a half million cycles. Tightening torques were measured prior to the loading. Removal torques were measured after cyclic loading. The data were analyzed with one-way analysis of variance (ANOVA), and the significance level was set at P < .05. RESULTS: The mean removal torques after cyclic loading were 34.0 ± 1.1 Ncm (group S), 25.0 ± 1.5 Ncm (group SI), 23.9 ± 2.1 Ncm (group ID), and 27.9 ± 1.3 Ncm (group BSB). Removal torques of each group were statistically different in the order of group S > group BSB > groups SI and ID (P < .05). The mean reduction rates were -2.9% ± 3.2% (group S), -21.9% ± 4.8% (group SI), -20.2% ± 7.2% (group ID), and -6.9% ± 4.3% (group BSB) after a half million cycles, respectively. Reduction rates of groups S and BSB were statistically lower than those of groups SI and ID (P < .01). The standard deviation of group S was lower than group BSB. CONCLUSION: The removal torque of the original Straumann abutment was significantly higher than those of the copy abutments. The reduction rate of the groups S and BSB abutments was lower than those of the other copy abutments.

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.

Esthetic Evaluation of Implant Crowns and Peri-Implant Soft Tissue in the Anterior Maxilla: Comparison and Reproducibility of Three Different Indices.

BACKGROUND: A successful implant reconstruction with optimal esthetics consists of a visually pleasing prosthesis and complete and healthy surrounding soft tissue. In the current literature, numerous indices used to qualitatively assess esthetics have been described. However, studies comparing the indices and their reproducibility are scarce. PURPOSE: The aim of this study was to compare three different esthetic indices for the evaluation of single implant-supported crowns. MATERIALS AND METHODS: A total of 10 prosthodontists (P), 10 orthodontists (O), 10 general dentists (G), and 10 lay people (L) independently performed the same assessment using 30 photographs and corresponding casts with three different esthetic indices (Peri-Implant and Crown Index [PICI], Implant Crown Aesthetic Index [ICAI], "Pink Esthetic Score/White Esthetic Score [PES/WES]) and repeated the evaluations 4 weeks later. RESULTS: The PES/WES and the PICI showed significantly higher esthetic scores (pink, white, total) and clinical acceptance compared with the ICAI in all four groups and in both assessments. The highest intraobserver agreement was achieved using the PES/WES and the least with the ICAI. The mean Kappa per group ranged from 0.18 (group L with ICAI) to 0.63 (group G with PICI). CONCLUSION: In comparison with the ICAI, the PES/WES and PICI were more reproducible. Therefore, PES/WES and PICI seem to be more suitable as esthetic indices for single implant crowns.

Malpositioned implants in the anterior maxilla: a novel restorative approach to reestablish peri-implant tissue health and acceptable esthetics. Part I. Case presentation and treatment options.

This two-part case presentation describes the prosthetic challenge of managing complications after inadequate esthetic risk assessment, treatment planning, and implant positioning in the anterior maxilla. Here, the case report of a 50-year-old woman, referred after inappropriate execution of immediate implant placement, is presented. Different restorative treatment alternatives are proposed, excluding major surgical procedures. In the next part of the article, the advantages and shortcomings of the various prosthetic options will be discussed and the selected treatment revealed. The aim of this part of the article is to illustrate the importance of treatment planning, emphasizing that the correction of esthetic implant failures consistently leads to compromised results when compared to what could have been achieved first time round.

Malpositioned implants in the anterior maxilla: a novel restorative approach to reestablish peri-implant tissue health and acceptable esthetics. Part II: Case report and discussion.

This two-part case presentation describes the prosthetic challenge of managing complications in a 50-year-old female patient after inadequate esthetic risk assessment, treatment planning, and implant placement in the anterior maxilla. In Part I, the clinical situation was described, and different restorative solutions were proposed to correct the extreme facial inclination of the implants, excluding major surgical procedures, namely implant removal. In Part II, different prosthetic options are discussed, and the final treatment is revealed. A noninvasive treatment protocol was applied to transform a severely compromised postsurgical situation into an esthetically acceptable result. An unconventional prosthesis design was implemented, including the use of ceramic veneers bonded to the CAD/CAM-generated screw-retained zirconia- based fixed dental prosthesis (FDP), to correct major axis-related problems and spatial discrepancies.

Biologic width around different implant-abutment interface configurations. A radiographic evaluation of the effect of horizontal offset and concave abutment profile in the canine mandible.

PURPOSE: The purpose of this experimental study was to analyze radiographically in a dog model how different implant-abutment interface configurations influence alveolar crestal bone changes. MATERIALS AND METHODS: Six different experimental implant-abutment connections were evaluated in six mixed-breed dogs. The following parameters were tested: absence of microgap, microgap proximal to bone crest, and microgap distant from bone crest. In addition, two different cervical abutment profiles, one straight and one featuring a supracrestal concavity, were evaluated. Implants were based on a cylindrical full-body screw design and made from cold-worked grade IV commercially pure titanium. The diameter (at thread tips) measured 4.1 mm, whereas the inner diameter was 3.5 mm. Standardized periapical digital radiographs were obtained for comparative analysis at baseline and at 3, 4, 5, 6, 7, 8, and 9 months after implant placement. Radiographs were randomized and calibrated for linear measurements. For statistical analysis, mixed-model repeated-measures analysis of variance was used. RESULTS: All implants integrated successfully and remained stable during the entire period of the study. Radiographically, when comparing groups with straight profiles, crestal bone remodeling in group C (one-piece design) was significantly less than in group A (matching diameters) and B (nonmatching diameters). In fact, implant group C showed the least crestal bone remodeling of all groups. When comparing groups with a concave profile but different microgap configurations, all three designs demonstrated bone loss with no significant differences among the three groups. CONCLUSION: A nonsubmerged one-piece implant design demonstrated the least amount of bone remodeling of all groups. Implant-abutment connections with a concave profile established crestal bone levels immediately apical to the concavity regardless of the microgap variable.

Quantitative three-dimensional methodology to assess volumetric and profilometric outcome of subepithelial connective tissue grafting at pontic sites: a prospective pilot study.

The aim of this study was to describe a technique for the assessment of soft tissue volumetric and profilometric changes. The technique has been applied at the alveolar contour of mild to moderate horizontal ridge defects after soft tissue augmentation at pontic sites. A quantitative three-dimensional (3D) analysis based on laser scanning was used for the measurement of volume gain and horizontal changes of alveolar profile 5 months after a subepithelial connective tissue graft using a pouch approach in five patients. All the surgical sites healed uneventfully. A mean soft tissue volume increase of 35.9 mm3 was measured 5 months after the grafting procedure. The linear measurements showed that, in the area where the augmentation was performed, the distance between the preoperative vestibular profile and the postoperative one ranged from 0.16 to 2 mm. The described quantitative measurements based on 3D laser scanning appear to be an effective method for assessment of soft tissue changes in future studies. Additionally, within the limitation of a small sample size, the present data suggest that the investigated surgical technique can be considered when corrections of mild to moderate alveolar horizontal ridge atrophies at maxillary lateral incisor edentulous gaps are necessary.

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.

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.

Peri-implant soft tissue conditioning with provisional restorations in the esthetic zone: the dynamic compression technique.

An optimal esthetic implant restoration is a combination of a visually pleasing prosthesis and surrounding peri-implant soft tissue architecture. This article introduces a clinical method, the dynamic compression technique, of conditioning soft tissues around bone-level implants with provisional restorations in the esthetic zone. The technique has several goals: to establish an adequate emergence profile; to recreate a balanced mucosa course and level in harmony with the gingiva of the adjacent teeth, including papilla height/width, localization of the mucosal zenith and the tissue profile's triangular shape; as well as to establish an accurate proximal contact area with the adjacent tooth/implant crown.

Long-term stability of contour augmentation with early implant placement following single tooth extraction in the esthetic zone: a prospective, cross-sectional study in 41 patients with a 5- to 9-year follow-up.

BACKGROUND: Early implant placement with simultaneous contour augmentation is documented with short- and medium-term studies. The long-term stability of contour augmentation is uncertain. METHODS: In this prospective, cross-sectional study, 41 patients with an implant-borne single crown were examined twice, in 2006 and 2010. Clinical, radiologic, and esthetic parameters were assessed at both examinations. In addition, a cone beam computed tomographic (CBCT) image was obtained during the second examination to assess the dimensions of the facial bone wall. RESULTS: All 41 implants demonstrated ankylotic stability without signs of peri-implant infection at both examinations. The clinical parameters remained stable over time. Satisfactory esthetic outcomes were noted, as assessed by the pink and white esthetic score (PES/WES) indices. Overall, the PES scores were slightly higher than the WES scores. None of the implants developed mucosal recession over time, as confirmed by values of the distance between implant shoulder and mucosal margin and cast measurements. The periapical radiographs yielded stable peri-implant bone levels, with a mean distance between implant shoulder and first visible bone-implant contact value of 2.18 mm. The CBCT analysis demonstrated a mean thickness of the facial bone wall ≈2.2 mm. In two implants (4.9%) no facial bone wall was detectable radiographically. CONCLUSIONS: This prospective cross-sectional study demonstrates stable peri-implant hard and soft tissues for all 41 implants examined and satisfactory esthetic outcomes overall. The follow-up of 5 to 9 years confirmed again that the risk for mucosal recession is low with early implant placement. In addition, contour augmentation with guided bone regeneration was able to establish and maintain a facial bone wall in 95% of patients.

Efficacy and predictability of short dental implants (<8 mm): a critical appraisal of the recent literature.

PURPOSE: This review of literature was conducted to evaluate the predictability of treatment outcomes with short dental implants (SDI), ie, implants shorter than 8 mm. MATERIALS AND METHODS: The review included studies, published between January 1990 and July 2011, that (1) involved SDI (<8 mm) placed in human jaws, (2) had a minimum of 20 SDI in their analysis, (3) provided data on survival rates, and (4) reported a minimum observation period of at least 3 months after placement. RESULTS: Forty-one studies fulfilled the above criteria; only 17 of these studies reported outcomes with microrough surface SDI. Six different lengths (4, 5, 6, 6.5, 7 and 7.5 mm) of microrough surface SDI with varying diameters (3.5 to 6 mm) were identified in the studies. A total of 1,828 microrough surface SDI were inserted and 45 failures were reported. Observation periods ranged from 3 months to 9 years. The reported survival rates for SDI ranged from 92.2% to 100%. From a total of 1,123 SDI inserted in specified jaw locations, failures were observed more often in the maxilla (n=297, failed=13) than in the mandible (n=826, failed=19). The review did not identify any correlation between implant diameter and survival for the microrough SDI. CONCLUSIONS: Microrough surface short implants (6 to 7.5 mm) appear to provide favorable survival rates and, therefore, can be predictably employed for simplification of implant therapy in situations of reduced alveolar heights in the posterior jaw segments.