Clinical Evaluation of 209 All‐Ceramic Single Crowns Cemented on Natural and Implant‐Supported Abutments with Different Luting Agents: A 6‐Year Retrospective Study

Background: The Procera AllCeram? system (Nobel Biocare AB, Göteborg, Sweden) is a valid alternative to metal–ceramic restorations. However, limited long‐term data of its use for single crowns on natural and implant‐supported abutments are available. Purpose: The present study aimed at evaluating the clinical performances of Procera AllCeram single crowns in both anterior and posterior regions of the oral cavity either on natural tooth or implant abutments over a period of 6 years. Materials and Methods: Two hundred nine single crowns were fabricated and used in 112 patients. Zinc phosphate and resin luting agents were used to cement the restorations. The crowns were evaluated according to the California Dental Association's quality assessment system. Results: Three crowns were lost at follow‐up. Of the 206 restorations, which completed the 6‐year follow‐up, 9 crowns were affected by mechanical complications and 7 crowns failed. All surviving crowns were ranked as either excellent or acceptable. Cumulative survival and success rates of 95.2 and 90.9%, respectively, were recorded. Conclusions: Within the limitations of the present study, Procera AllCeram crowns proved to be a reliable clinical option to restore both anterior and posterior missing teeth either on natural or implant abutments. The resin cement used in the present study performed better than the zinc phosphate luting agent.     

Clinical performance of a method for the fabrication of implant-supported precisely fitting titanium frameworks: a retrospective 5- to 8-year clinical follow-up study

Background: The CrescoTi Precision® (CTiP) method (CrescoTi Systems, Lausanne, Switzerland) has been introduced as an alternative method for the fabrication of precisely fitting titanium frameworks. The method is supposed to be used with all major implant systems, without the need for abutments. Purpose: The objectives of this clinical and radiographic retrospective follow‐up study were to report the clinical performances of “CTiP‐fabricated” frameworks that are screw retained directly to Brånemark implants as opposed to Brånemark implant/abutment assemblies (Nobel Biocare AB, Gothenburg, Sweden) and to compare the clinical outcomes of these two modalities. Materials and Methods: Thirty‐six patients were provided with 46 fixed prostheses supported by 207 Brånemark regular‐platform implants. Twenty‐seven prostheses were placed on implant/abutment assemblies, and 19 were placed directly at “implant level.” The prostheses had been in function for 5 to 8 years at the time of the final examinations. Results: Three patients did not attend the final examination. All 43 prostheses in the 33 examined patients were still in function. No major mechanical framework complications were observed during the observation period. One implant was lost after loading. There was no difference in bone loss around the abutment‐free implants when compared with the implants provided with abutments. Conclusions: This long‐term clinical test demonstrated that the CTiP technology constitutes a reliable prosthetic treatment concept in combination with Brånemark implants. The results also revealed that the frameworks could be connected directly to the implants without any negative consequences.     

Long‐Term Follow‐Up of CeraOne™ Single‐Implant Restorations: An 18‐Year Follow‐Up Study Based on a Prospective Patient Cohort

Background: Knowledge on long‐term clinical performance of more than 5 years on the single‐implant CeraOne? (Nobel Biocare AB, Gothenburg, Sweden) concept is limited. Purpose: The aim of this study is to report the long‐term clinical performance of the first CeraOne single‐implant restorations, installed 17 to 19 years ago. Materials and Methods: The group comprised 57 patients provided with 65 CeraOne single‐tooth restorations. Sixty‐two all‐ceramic and three metal‐ceramic crowns were cemented between 1989 and 1991. Patients were followed up clinically and with intraoral radiographs at placement, after 1, 5, and between 17 and 19 years after placement. Results: Data were available for altogether 48 patients, followed up on an average time of 18 years. Excluding deceased patients (n = 2) and failed implant patients (n = 2), only five patients were lost to follow‐up (8.8%). Two implants failed, resulting in an 18‐year implant cumulative success rate (CSR) of 96.8%, and altogether eight original single‐crown restorations were replaced (CSR 83.8%). The most common reason for crown replacement was infra‐position of the implant crown (n = 3). Many of the remaining original crowns showed various signs of implant crown infraposition at the termination of the study. In general, the soft tissue at the restorations was assessed to be healthy and comparable with the gingiva at the adjacent natural teeth. Bone levels were on an average stable with only few patients exhibiting bone loss of more than 2 mm during 18 years in function. Conclusion: This long‐term follow‐up study of single‐implant restorations shows encouraging results with few implant failures and minimal bone loss over an 18‐year period. Original single‐crown restorations were replaced more frequently, because of, for example, implant crown infraposition and veneer fractures. The CeraOne concept proved to be a highly predictable and safe prosthodontic treatment.     

A 4-year prospective clinical and radiological study of maxillary dental implants supporting single-tooth crowns using early and delayed loading protocols

Background: Recent studies have showed that immediate/early loading of dental implants is a clinically feasible concept with results similar to those for standard two‐stage procedures, especially in the mandible. However, there are only a few studies regarding the immediate/early loading of maxillary implants supporting single‐tooth crowns. Purpose: The aim of this study was to compare the clinical and radiological outcomes of early‐ and delayed‐loaded dental implants supporting single‐tooth crowns in the maxilla. Materials and Methods: Twenty‐nine patients were consecutively treated between 2000 and 2002 with 59 Brånemark System MK III TiUnite implants (Nobel Biocare AB, Göteborg, Sweden) in the maxilla. Two groups were formed according to the loading protocols. In the test group, definitive implant‐supported single crowns were delivered to 19 patients 6 weeks after the implant placement. In the control group, definitive implant‐supported single crowns were delivered to 10 patients 6 months after the implant placement. Clinical and radiographic parameters were recorded at baseline, 1 to 4 years. Implant stability measurements have only been performed at 4‐year follow‐up recall. Results: Overall, three implants were lost during the study period. Two implants were lost in the test group including 36 implants, which indicated a survival rate of 94.4%. One of the lost implants was replaced and then osseointegrated successfully. One implant was lost in the control group during the healing period, which indicated a survival rate of 95.7%. The average marginal bone loss was 1.11 mm for 56 implants after 4 years. There were no significant differences in marginal bone levels, insertion torque, and resonance frequency values between the two groups. Conclusion: The results of this study indicate that 6 weeks of early loading period for TiUnite‐surface titanium implants in the maxilla is reliable and predictable for this patient population and may offer an alternative to the standard loading protocol.     

Single Implant Treatment in Healing versus Healed Sites of the Anterior Maxilla: A Clinical and Radiographic Evaluation

Purpose: The aim was to document the Nobelreplace tapered TiUnite® (Nobel Biocare, Göteborg, Sweden) implant system used by experienced clinicians in daily practice for replacing single maxillary anterior teeth and to compare the clinical and radiographic outcome between implants installed in healing sites (early implant placement) and fully healed sites (conventional implant placement) after on average two and a half years of function. Material and Methods: A cross‐sectional study in patients who had been treated by two periodontists and two prosthodontists in 2006 and 2007 was conducted. Surgical treatment involved standard flap elevation without releasing incisions and restorative procedures included cemented crowns in all patients. Only straightforward single implant treatments in healing sites (6–8 weeks following tooth extraction) and fully‐healed sites (≥6 months following tooth extraction) were considered with both neighboring teeth present and without the need for hard and/or soft tissue grafting. Clinical and radiographic analyses of all implants were performed by a blinded clinician who had not been involved in the treatment. Results: Forty‐nine of the 53 eligible single implants (22 early and 27 conventionally placed implants) in 44/48 patients were available for scrutiny. There was no significant difference in implant survival between early (95%) and conventionally (93%) installed implants (p = 1.000). Mean bone level to the implant‐abutment interface was 1.25 and 1.02 mm for early and conventional implant placement, respectively (p = .220). In spite of fairly low plaque levels (26%), overall peri‐implant bleeding was quite prevalent (36%). Mean peri‐implant probing depth was 3.3 mm. Five restorations had experienced technical complications. Conclusions: Single Nobelreplace tapered TiUnite® implants installed in healing as well as in healed sites of the anterior maxilla are predictable. Both strategies seem equally successful in terms of implant survival, bone remodeling, clinical response, and risk for complications.     

Immediate provisional for single-tooth implant replacement with Brånemark system: preliminary report

Background: The success of osseointegrated implants ad modum Brånemark for single‐tooth restorations is documented. Future developments should aim at improving the benefits to patients by decreasing treatment time, minimizing surgical stages, and maximizing esthetic outcomes. Using knowledge from studies of immediate implant placement, one‐stage, immediate loading protocols, the authors developed the immediate provisional. Purpose: The purpose of this study was to develop a protocol to provide an immediate solution for restoring a single missing tooth in the esthetic zone. The protocol should be simple, predictable, cost effective, and allow the use of other techniques to improve esthetic outcome. Materials and Method: This prospective clinical study included 24 patients treated from August 1999 to October 2000. Single‐tooth implant replacement was done according to immediate provisional protocol. Thirteen of the 24 patients had immediate implant placement after tooth extraction. All implants were placed in the esthetic zone. During surgery, emphasis was placed on obtaining primary stability by achieving bicortical anchorage and maximum insertion torque of at least 40 Ncm. CeraOne (Nobel Biocare) abutments were used, and provisional crowns were fabricated immediately before wound closure. The occlusion was protected by adjacent teeth. Results: Within the follow‐up period of between 1 month and 15 months, all fixtures in the 24 patients were stable. Crestal bone loss greater than one thread‐width was not detected. The esthetic result was considered satisfactory by all patients. Conclusions: The implant placement and restoration protocol used in this study showed promising initial results for both the immediate implant and healed extraction site groups. The desirable goals of patient satisfaction, excellent esthetic outcomes, and no increase in treatment cost were achieved in this protocol. Further studies to elucidate the potential of the immediate provisional protocol are justified.     

The implant-abutment interface of alumina and zirconia abutments

Background: Although ceramic and titanium abutments are widely used in clinical practice, the mechanical characterization of the implant‐abutment interface for ceramic abutments has not been evaluated after the dynamic loading. Purpose: The purpose of this study was to assess the implant‐abutment interface after the dynamic loading of titanium, alumina, and zirconia abutments. Materials and Methods: Fifteen aluminum oxide, zirconium oxide, and titanium abutments were manufactured by the Procera System® (Nobel Biocare AB, Göteborg, Sweden) and were connected to Ø 3.75 × 13‐mm regular platform implants (MK III, Nobel Biocare AB) secured in a 30° inclined plane. A mechanical testing machine applied compressive dynamic loading between 20 and 200 N at 1 Hz on a standard contact area of copings cemented on abutments for 47.250 cycles. The measurements of microgaps at the implant‐abutment interface from the labial, palatinal, mesial, and distal surfaces of each specimen were undertaken by scanning electron microscope analyses prior to and after the experiments. The data of the microgaps before and after the dynamic loading were statistically assessed using the Wilcoxon signed rank test and the Kruskal–Wallis variance analysis (α = 0.05). Results: Coping fracture, abutment fracture, or abutment screw loosening or fracture was not detected in any specimen during the entire test period. After the dynamic loading, the titanium abutment control group revealed an increased microgap (3.47 µm) than zirconia (1.45 µm) and alumina (1.82 µm) groups at the palatinal site (p < .05). The mean measurement values at different measurement sites of specimens within and between each abutment group were similar (p > .05). Conclusion: Owing to their comparable microgap values at the implant‐abutment interface after the dynamic loading, ceramic abutments can withstand functional forces like conventional titanium abutments.     

A Retrospective Comparison of Oxidized and Turned Implants with Respect to Implant Survival,Marginal Bone Level and Peri‐Implant Soft Tissue Conditions after at Least 5 Years in Function

Background: Long‐term clinical follow‐up studies comparing different implant surfaces with regard to survival and marginal conditions are rare. Objectives: The objective of this study was to compare the clinical performance of turned and oxidized implants after more than 5 years of loading Material and Methods: One hundred three patients (43 men, 60 women; mean age 67.4 years, range 32–90) previously treated with 287 implants (Nobel Biocare AB, Gothenburg, Sweden), 133 with turned surface (MKIII, Nobel Biocare AB) and 154 with an oxidized surface (MKIII, TiUnite, Nobel Biocare AB) were examined after at least 5 years of loading (mean 82 months, range 60–93 months). The implants had been used for support of single crowns (33 patients/36 implants), partial bridges (39 patients/103 implants), or full bridges (31 patients/148 implants) following an early loading protocol (14 patients /54 implants), a one‐stage protocol (32 patients/59 implants) or a two‐stage protocol (57 patients/174 implants). Clinical examinations of bleeding on probing (BoP) and pocket depth (PD) were performed. Intraoral radiographs were used for assessments of marginal bone levels (MBLs). Results: Seven turned implants and one oxidized implant failed, giving overall cumulative survival rates of 94.7 and 99.4%, respectively. There were no differences for BoP scores (0.5 ± 0.7 vs 0.4 ± 0.6) and PD measurements (1.7 ± 0.8 mm vs 1.8 ± 1.0 mm) parameters when comparing turned and oxidized implants, respectively. The mean MBL was 1.8 ± 0.8 mm and 2.0 ± 0.9 mm for turned and oxidized implants, respectively, after more than 5 years in function (NS). Frequency distribution of MBL loss showed no statistically significant differences between the two surfaces. A total of four implants (1.4%) (three oxidized and one turned) showed a PD > 3 mm, MBL > 4 mm, and BoP. However, none of these were associated with suppuration on examination. Conclusion: The present study does not state any differences in implant failure, MBL, presence of bleeding or PD around implants when comparing turned and oxidized titanium implants after at least 5 years of function.     

Long‐Term Function of Single‐Implant Restorations: A 17‐ to 19‐Year Follow‐Up Study on Implant Infraposition Related to the Shape of the Face and Patients' Satisfaction

Background: Various levels of infraposition of single‐implant restorations have been observed in long‐term follow‐up studies, but little knowledge is available on the biological mechanism behind this pattern. Purpose: The primary aim of this study is to report the frequency and severeness of implant infraposition in the anterior single‐implant application after 17 to 19 years in function and, secondly, to try to relate these observations to anatomical appearance of the shape of the face of the patient. Materials and Methods: The present study comprised of 57 patients who were provided with 65 CeraOne? single‐tooth restorations (Nobel Biocare AB, Gothenburg, Sweden) between 1989 and 1991. Altogether 46 of these patients were treated with single implants in the anterior region. Besides clinical and radiographic data, clinical photographs, study casts, and patient's assessment of the long‐term aesthetic result (visual analog scale) was collected at the termination of the present study. The degree of implant crown infraposition was related to assessed facial shape and to patient and clinical assessment of the aesthetic result by means of Pearson's correlation test. To increase the numbers of patients, another group of 25 patients presented in another similar study were pooled with the present material for prevalence calculations. Results: Altogether 47 patients showed up for the final examination after an average of 18 years (82%). Two implants failed (18 years cumulative survival rates [CSR]– 96.8%) and eight original single‐crown restorations were replaced (CSR 83.8%). Three of the replaced crowns were replaced because of infraposition of the crowns. About 40% of the patients showed signs of infraposition, similar in younger and older age groups, but more frequently observed in female patients at termination of the study (p < 0.05). There was a weak trend indicating an association between “long‐face” appearance and infraposition of the crown restoration (p > 0.05), and patients were more satisfied with the aesthetic clinical result than the participating clinicians (p < 0.05). Conclusion: Single‐implant restorations in the anterior upper jaw may present small degrees of infraposition in long‐term perspectives. Female patients seem to be at a higher risk of infraposition (p < 0.05), but no clear relationship between age at implant placement or facial shape and degree of infraposition was possible to establish (p > 0.05). Patients were more satisfied with the aesthetic result, as compared with the clinicians (p < 0.05), and patients seemed to pay less attention to the degree of infraposition in their aesthetic assessments, as compared with most of the clinicians.     

Mk III: a third generation of the self-tapping Brånemark System implant, including the new Stargrip internal grip design. A 1-year prospective four-center study

Background: Many prospective studies have shown predictable long‐term results of the Brånemark System (Nobel Biocare AB, Gothenburg, Sweden) turned‐surface implants in totally edentulous, partially edentulous, and single cases. The Mk III self‐tapping implant was introduced by Nobel Biocare in 1999 as part of a new implant generation that improved on the Mk II self‐tapping implant that had been introduced in 1992. A new implant design should always be evaluated, preferably in prospective multicenter studies. Purpose: The aim of the present prospective multicenter study was to evaluate the short‐term success rate of the Br ? nemark Mk III machined‐ and turned‐surface self‐tapping implant and to evaluate the clinical handling of the new Stargrip (Nobel Biocare AB) internal grip design. Materials and Methods: The open prospective 1‐year multicenter study was performed at four clinics. Sixty‐four patients (38 females, 26 males) with a mean age of 51 years (range, 16 to 80 years) were included. Seventeen of the patients were totally edentulous, 26 were partially edentulous, and 21 had single‐tooth losses. In total, 194 Mk III implants were inserted, 89 in the maxillas and 105 in the mandibles. Results: Fifty‐eight patients were observed for 1 year after prosthetic loading. Three of 194 implants were lost, corresponding to a cumulative success rate of 98.4% after 1 year, 100% for maxillary implants and 97.1% for mandibular implants. The implant driver carried the implants reliably in 99.5% of all treated patients. Sixty‐two patients received the planned prosthetic reconstruction. All but one prosthetic reconstruction survived after 1 year of loading. The mean marginal bone resorption, analyzed from radiographs of 143 implants, was 1.15 mm (standard deviation [SD], 1.09 mm) from the second‐stage surgery to the 1 ‐year follow‐up. Conclusion: The 1‐year success rate of the Mk III implant was high, and the clinical handling of the internal grip design (Stargrip) improved the surgical technique and was well appreciated by both surgeons and assisting staff.     

Immediate loading of Brånemark implants: a 24-month follow-up of a comparative prospective pilot study between mandibular overdentures supported by Conical transmucosal and standard MK II implants

Background: The purpose of this prospective study is to compare the long‐term outcome of immediately loaded implantretained mandibular overdentures supported by four screw‐type one‐piece transmucosal implants with that of four screw‐type two‐piece implants inserted in the interforaminal area of the mandible and rigidly connected by a U‐shaped curved Materials and Methods: A prospective pilot study was conducted with 10 patients receiving an implant‐supported overdenture in the mandible. The patients were randomly assigned to two groups. In the control group (five patients), four standard Brånemark implants (MK II; Nobel Biocare AB, Gothenburg, Sweden), 3.75 mm large and at least 10 mm long, were sited anterior to the mental foramina, and four standard abutments (Nobel Biocare AB) for bar construction were immediately screwed to the implants. In the test group (five patients), four conical transmucosal implants (Nobel Biocare AB), 3.75 mm large and at least 9 mm long in the threaded part, were sited anterior to the mental foramina. Immediately after implant placement, a U‐shaped gold or titanium bar was fabricated and implants were immediately loaded (within 24 h) in both groups with an implant‐retained overdenture. The patients were followed up for a minimum of 24 months. Implants were evaluated at the time of immediate loading and at 12 and 24 months after prosthetic loading, with the following parameters: modified plaque index (MPI), modified bleeding index (MBI), and probing depth (PD). Periimplant bone resorption was evaluated on panoramic radiographs taken 12 and 24 months after the beginning of prosthetic loading. Results: No significant differences were found between the two groups with regard to MPI, MBI, PD, and periimplant bone resorption at 12 and 24 months. The cumulative success rate of implants according to the criteria proposed by Albrektsson and colleagues was 100% in both groups after 2 years of functional loading. Conclusions: Results from this study demonstrated that the success rate for immediately loaded mandibular implants is similar to that obtained in cases of delayed loading and that there are no significant differences between results with two‐piece implants and one‐piece transmucosal implants.     

Fracture Strength and Failure Mode of Maxillary Implant-Supported Provisional Single Crowns: A Comparison of Composite Resin Crowns Fabricated Directly Over PEEK Abutments and Solid Titanium Abutments

Background: Polyetheretherketone (PEEK) temporary abutments have been recently introduced for making implant‐supported provisional single crowns. Little information is available in the dental literature on the durability of provisional implant‐supported restorations. Purpose: The objectives of this study were to evaluate the fracture strength of implant‐supported composite resin crowns on PEEK and solid titanium temporary abutments, and to analyze the failure types. Material and Methods: Three types of provisional abutments, RN synOcta Temporary Meso Abutment (PEEK; Straumann), RN synOcta Titanium Post for Temporary Restorations (Straumann), and Temporary Abutment Engaging NobRplRP (Nobel Biocare) were used, and provisional screw‐retained crowns using composite resin (Solidex) were fabricated for four different locations in the maxilla. The specimens were tested in a universal testing machine at a crosshead speed of 1 mm/minute until fracture occurred. The failure types were analyzed and further categorized as irreparable (Type 1) or reparable (Type 2). Results: No significant difference was found between different abutment types. Only for the position of the maxillary central incisor, composite resin crowns on PEEK temporary abutments showed significantly lower (p < 0.05) fracture strength (95 ± 21 N) than those on titanium temporary abutments (1,009 ± 94 N). The most frequently experienced failure types were cohesive fractures of the composite resin crowns (75 out of 104), followed by screw loosening (18 out of 104). According to reparability, the majority of the specimens were classified as Type 1 (82 out of 104). Type 2 failures were not often observed (22 out of 104). Conclusions: Provisional crowns on PEEK abutments showed similar fracture strength as titanium temporary abutments except for central incisors. Maxillary right central incisor composite resin crowns on PEEK temporary abutments fractured below the mean anterior masticatory loading forces reported to be approximately 206 N.     

Measurements comparing the initial stability of five designs of dental implants: a human cadaver study

Background: A number of different dental implant designs are currently in clinical use. A successful outcome of implant placement is thought, at least in part, to be due to the primary stability of an implant after placement. Few data are available for comparing the primary stability characteristics of different implant designs. Purpose: This investigation compared the primary stability of five types of endosseous dental implant of varying geometry and surface topography. Materials and Methods: Comparison was made between a standard threaded commercially pure titanium implant (Nobel Biocare AB, Göteborg, Sweden), the Mark II self‐tapping implant (Nobel Biocare AB, Göteborg, Sweden), the Mark IV tapered self‐tapping implant (Nobel Biocare AB, Göteborg, Sweden), the Astra Tioblast (AstraTech AB, Mölndahl, Sweden), and the 3i Osseotite (3I [Implant Innovations Incorporated], Palm Beach, Florida, USA). Fifty‐two fixtures were placed in the maxillary bone of nine unembalmed human cadavers. Implant stability as a function of peak insertion torque and resonance frequency values was recorded for each fixture site after placement. Removal torque was also measured 1‐hour postinsertion. Assessment of bone quality at each site was made. Results: All of the implants tested demonstrated good primary stability in type 2 and 3 bone. The Standard, Mark II, Osseotite, and Tioblast were less stable when placed into bone type 4. The Mark IV implants appeared to maintain a high primary stability even in Type 4 bone. Conclusion: When looking across all bone qualities, the Mark IV implant develops a significantly higher insertion torque than the Standard, Mark II, and Osseotite implant types, and a significantly higher resonance frequency value than the Standard implant, indicating a higher interfacial stiffness at the implant–bone interface.     

The Precision of Fit of Milled Titanium Implant Frameworks (I‐Bridge®) in the Edentulous Jaw

Background: New computer numeric controlled (CNC)–milled frameworks for implant‐supported prostheses have been introduced. However, no data are available on the precision of fit of these new frameworks. Purpose: The purpose of this study is to evaluate the precision of fit of a new CNC‐milled framework technique (I‐Bridge®, Biomain AB, Helsingborg, Sweden) using Brånemark System® (Nobel Biocare AB, Göteborg, Sweden) and NobelReplace? (Nobel Biocare AB) system implants. Materials and Methods: Ten test frameworks were fabricated for one master model for each implant system. Five additional frameworks were fabricated for five different models simulating clinical cases as controls (Brånemark System). The distortion of implant center point positions was measured in x‐, y‐, and z‐axes and in three dimensions by using a contact‐type coordinate measuring machine and a computer program developed specifically for this purpose. Mann–Whitney U‐test was used to compare differences of distortion within and between the groups. Results: The maximal distortion in arch width (x‐axis) and curvature (y‐axis) was within 71 and 55 µm for all frameworks, respectively. The mean distortion in absolute figures in x‐, y‐, z‐axes and three dimensions was for “clinical control” frameworks 23, 26, 4, and 34 µm as compared with less than 12, 12, 2, and 17 µm for Brånemark and NobelReplace frameworks, respectively. Control frameworks showed significantly (p < .05) greater mean and range of distortions in x‐ and y‐axes and in three dimensions compared with test frameworks. Conclusion: All measured frameworks presented signs of misfit, indicating that no framework had a “passive fit.” Frameworks produced in a more routine clinical environment seem to present greater levels of distortion as compared with frameworks produced in a strict test situation. However, all measured frameworks presented levels of precision of fit within limits considered to be clinically acceptable in earlier studies of frameworks placed on abutments.     

A 10‐year retrospective analysis of marginal bone‐level changes around implants in periodontally healthy and periodontally compromised tobacco smokers

Aim: To compare the 10‐year marginal bone loss rates around implants supporting single‐unit crowns in tobacco smokers with and without a history of treated periodontitis. Materials and methods: In this retrospective controlled study, 40 tobacco smokers were divided into four groups of 10 patients each. Two groups of periodontally compromised (PC) patients and two groups of periodontally healthy (PH) patients were established. PC patients had been treated for their periodontal conditions before implant placement. All patients were enrolled in a regular, individually tailored maintenance care program. For the rehabilitation of PC and PH patients, two different types of implants were used (Nobel Biocare AB; Straumann^® Dental Implant System). The radiographic bone loss rate was calculated by subtracting the bone levels at the time of crown delivery from the bone levels at the 10‐year follow‐up. Results: The mean age, mean full‐mouth plaque score and full‐mouth bleeding score and implant location were similar for the four groups. Implant survival rates ranged between 70% and 100%, without statistically significant differences between the four groups (P>0.05). Implants placed in PC patients yielded statistically significantly higher marginal bone loss rates compared with those in PH patients (P<0.05), independent of the implant system used. Conclusion: After 10 years, implants placed in tobacco smokers with a history of treated periodontitis and enrolled in a supportive therapy program yielded lower survival rates and higher marginal bone loss rates compared with those of implants placed in PH smokers. These outcomes were independent of the implant system installed or the healing modality applied. To cite this article:
Aglietta M, Iorio Siciliano V, Rasperini G, Cafiero C, Lang NP, Salvi GE. A 10‐year retrospective analysis of marginal bone‐level changes around implants in periodontally healthy and periodontally compromised tobacco smokers
Clin. Oral Impl. Res. 22 , 2011; 47–53.
doi: 10.1111/j.1600‐0501.2010.01977.x     

Comparison of fit accuracy between Procera custom abutments and three implant systems

Background: Although increase of misfit has been reported when associating implant and abutment from different manufacturers, Procera® (Nobel Biocare?, Göteborg, Sweden) custom abutment has been universally used in clinical practice. Purpose: The purpose of this investigation was to compare the vertical gap of zirconia Procera abutment associated with implants from the same manufacturer (Nobel Biocare) and two other implant systems. Materials and Methods: Twenty‐four zirconia Procera abutments were produced using computer‐assisted design and manufacture (CAD/CAM) and paired with (1) eight MK Iii RP 4.1 × 10 mm implants (Nobel Biocare) – GNB group; (2) eight Try on, 4.1 × 10 mm implants (Sistema de Implantes, São Paulo, Brazil) – ES group; and (3) eight Master screw, 4.1 × 10 mm implants (Conexão Sistema de Prótese, São Paulo, Brazil) – EC group. A comparison of the vertical misfit at the implant‐abutment interface was taken at six measuring sites on each sample using scanning electron microscopy with a magnification of 408×. One‐way analysis of variance was used to test for differences, and Tukey's test was used for pairwise comparison of groups (α = 0.05). Results: Significant differences relative to average misfit were found when Procera abutments were associated with other implant manufacturers. The ES group and EC group did not differ significantly, but both demonstrated significantly larger average misfit than the GNB group (p = .001). The average misfit was 5.7 µm ± 0.39, 9.53 µm ± 0.52 and 10.62 µm ± 2.16, respectively, for groups GNB, ES, and EC. Conclusion: The association of Procera zirconia abutment with other implant systems different from its manufacturer demonstrated significant alteration of vertical misfit at implant‐abutment interface.     

A Prospective Analysis of Immediate Provisionalization of Single Implants

Purpose: The purpose of this prospective study was to evaluate the viability of immediately provisionalized single‐tooth implants. Materials and Methods: One hundred forty patients (86 female, 54 male) with a mean age at implant placement of 45 years (range, 15–88 years) needing single‐tooth replacement, were treated between July 1999 and December 2004. Single‐tooth implants were placed and provisionalized the day of the surgery. All implants were manufactured by Nobel Biocare (Yorba Linda, CA) and had multiple diameters and configurations. The majority of the implants used in this study had oxidized titanium surfaces. The contours of the restorations were designed to mimic the original teeth and root forms. The morphology of the restorations provides support of the labial gingiva. Results: Over 5.5 years, 164 implants were placed and immediately provisionalized. Sixty‐four implants were placed immediately post extraction. Seven implants failed, yielding an overall survival rate of 95.73%. Conclusion: The application of an immediate provisionalization protocol to a single implant can be successful if the proper precautions are taken in achieving passive occlusion.     

Stability of the implant/abutment joint in a single-tooth external-hexagon implant system: clinical and mechanical review

Rigorous efforts have recently been made to reduce the recurrence of implant/abutment joint failure in single‐tooth implant restorations. However, the current knowledge about the stability of implant/abutment joints in an external hexagon implant system is incomplete. We reviewed clinical data regarding single‐tooth implant treatment with Brånemark implants, specifically the CeraOne abutment system (Nobel Biocare AB, Göteborg, Sweden). In vitro studies on joint stability were systematically assessed. Bending overload and the presence of misfit at the implant/abutment joint interface are the critical mechanical conditions that can make the joint unstable. Appropriate joint fitness and proper alignment of the implant should be assessed, and occlusal adjustment by narrowing the restoration width and flattening cuspal inclination should be applied to avoid bending moments caused by the lateral component of occlusal forces. Sufficient clinical reports of longer duration that evaluate and verify longer‐term success of the newly manufactured joint components were unavailable.     

A retrospective analysis of early and delayed loading of full-arch mandibular prostheses using three different implant systems: clinical results with up to 5 years of loading

Background: Early loading of implant‐supported prostheses in the edentulous mandible is widely accepted, but do the clinical results replicate those of delayed loading? Purpose: The aim of this study was to evaluate clinical outcome and patient satisfaction with early or delayed loading in patients treated with fixed prostheses, using three different implant systems. Materials and Methods: One hundred and nine consecutively treated patients received 490 implants supporting fixed prostheses; 82 patients with Brånemark System® implants (Nobel Biocare AB, Göteborg, Sweden), 16 with Astra Tech® implants (Astra Tech AB Dental Implant system, Mölndal, Sweden), and 11 with ITI® MonoType® implants (ITI Dental Implant System®, Institute Straumann AG, Waldenburg, Switzerland). Prostheses were placed within 2 to 3 weeks in 55 patients; 54 patients underwent a two‐stage procedure. Data were collected from patient records and radiographs; 83 patients attended a clinical examination and received a questionnaire. Results: All patients had fixed prostheses at follow‐up with a mean observation time of 3.5 years. Cumulative survival rates (CSRs) were 92.5% of prostheses and 94.4% of implants for early loading, and 98.0 and 97.9% for delayed loading. The mean radiographic bone loss after the first year was small, and at 5 years less than 0.2 mm for both groups. With early loading, significantly more prostheses (p < .05) needed adjustment or replacement. Conclusion: Statistically significantly more prostheses needed adjustment or replacement in the early group. The present study suggested lower CSRs for prostheses and implants in the early loading group after 5 years; the difference was not statistically significant. Larger study samples are needed to verify statistically small differences between treatment techniques.     

部分牙缺失种植即刻功能负荷的临床探讨

目的:对部分牙缺失种植即刻功能负荷进行临床探讨。方法:将NobelBiocare种植体植入颌骨内,种植体植入扭力必须达到35Ncm以上。选择永久基台接在种植体上,用一定的扭力拧紧基台,基台水平印模,按常规制作和即刻戴上临时塑料修复体。6周后再印模,制作和戴上烤瓷修复体。结果:36例65枚种植体中,下颌22例41枚种植体,上颌14例24枚种植体,修复后成功率为98.5%。结论:部分牙缺失种植即刻功能负荷初步临床结果是满意的,其长期效果有待进一步的观察。