Nobel Biocare AB Research Articles

The Effects of Insertion Approach on the Stability of Dental Implants.

Dental implant surgery involves the insertion of a dental implant into the alveolar bone; the success of the surgery depends on the initial stability of the implant. The objective of this study was to examine the effects of dental implant insertion approaches in clinical surgery and in accordance with the standards of American Society for Testing and Materials on initial implant stability. Three insertion approaches were used for dental implant placement (Branemark Systems NobelSpeedy Groovy, Nobel Biocare AB, Gothenburg, Sweden) in two types of artificial bone—good bone (GB) and poor bone (PB). The three insertion approaches were as follows: (1) continuous rotation insertion (CRI): using a torque testing machine to continuously screw in an implant to completion and (2 and 3) intermittent rotation insertion (IRI)_90 and IRI_80: using CRI to bury an implant to 90% and 80% of its full length followed by IRI to complete the implantation, respectively. The maximum insertion torque value (ITV), periotest value (PTV), and implant stability quotient (ISQ) were measured and compared. The results indicated that bone quality and insertion approach both affected implant stability. Insertion approaches affected all three implant stability indicators differently in the GB and PB groups (p = 0.008). In GB groups, the insertion approach primarily affected ITV, whereas in PB groups, it primarily affected PTV. The effect of the insertion approach was less apparent for ISQ. Overall, in both the GB and PB groups, the implant stability for IRI_80 was greater than that for IRI_90, and the implant stability for IRI_90 was greater than that for CRI. Future in vitro studies should adopt an insertion approach that complies with the clinical practice for dental implant surgery. Dentists should adjust the timing for IRI in dental implant surgery to achieve greater initial dental implant stability.

Clinical study with gradually anodized implants restored with two‐piece anodized abutments – preliminary results

Background: Surface chemistry and topography of the implant-abutment complex play a key role in the implant osseointegration and proper adhesion of the soft tissue to the restoration. To optimize tissue integration at every level, novel anodized implant and abutment surfaces were developed. The implant surface has a gradual change in topography designed to promote early osseointegration and to support stable marginal bone, while the new surface at the tissue-level base promotes undisturbed mucointegration. Aim/Hypothesis: This prospective study aims to evaluate the clinical performance of the gradually anodized implant surface and the smooth anodized abutment surface after 3-year of function. The primary outcome is soft tissue health, thickness and stability evaluated from implant insertion to the 3-year follow-up. Materials and Methods: Patients requiring one single tooth replacement in the premolar or molar area in either jaw were included. Variable thread tapered implants with gradual anodized surface (NobelActive TiUltra, Nobel Biocare AB, Gothenburg, Sweden) were placed in healed sites and an On1 base with anodized surface (On1 Base/Xeal; Nobel Biocare AB) was immediately attached to the implant, and subsequently connected to an On1 healing cap. Digital impressions were taken on the day of surgery, while the final prosthesis was placed after a 12- week healing period. Clinical follow-ups are planned at 6, 12, 24, and 36 months post final prosthetic delivery. The secondary endpoints include soft tissue health assessments, marginal bone levels and remodelling, and oral-health related quality of life based on OHIP-14 questionnaire. Data analysis is performed with SPSS v25 (IBM, Armonk, USA). Results: 60 patients enrolled in the study. As of May 1st, 57 patients (28 females, 29 males; mean age 51.8 ± 12.4 years) received an implant and abutment base each. Most of the implants (64.9%) were placed in hard bone (quality 1 and 2). The mean insertion torque was 58.7 ± 12.3 Ncm (n = 57) and all implants were rated as surviving and stable at both insertion and final prosthesis placement (n = 48). Keratinized mucosa status improved from implant insertion to final prosthesis delivery, with 91.7% of the implants demonstrating the best score at surgery and 100% at final prosthesis delivery (n = 48). Additional analyses including marginal bone levels, plaque accumulation, papilla index, bleeding index, and gingival index, as well as OHIP-14, pain assessment and patient satisfaction, collected until the final prosthetic delivery, will be shown at the time of poster presentation. Conclusions and Clinical Implications: Within the limitations of the short follow-up, 100% implant survival combined with improvement in keratinized mucosa status indicate that the novel anodized surfaces at implants and abutments are safe and promote excellent peri-implant tissue health at every level. Keywords: soft tissue integration, mucointegration, one abutment one time

Fourteen-year evaluation of posterior zirconia-based three-unit fixed dental prostheses: A Prospective clinical study of all ceramic prosthesis

Objectivesthe purpose of the present prospective trial was to evaluate the clinical performance of posterior 3-unit zirconia-based fixed dental prostheses (FDPs) after 14 years of clinical function. Methodsthirty-seven patients needing to replace either premolars or molars were involved and 48 FDPs were fabricated (Procera Zirconia, Nobel Biocare AB). Frameworks with a9 mm2 cross section of the connectors and 0.6 mm minimum thickness of the retainers were made by means of Procera Forte CAD-CAM System (Nobel Biocare AB). The patients were recalled after 6 and 12 months and then yearly up to a total follow-up of 14 years. Two independent survival curves for patients wearing 1 or 2 FDPs were calculated by means of Kaplan-Meier analysis and a log-rank test was performed in order to compare these curves. The United States Public Health Service criteria were used to examine technical and esthetic outcomes. The biological examination was performed evaluating plaque control, pocket depth, attachment level, bleeding on probing at both abutments and contralateral teeth and evaluated by means of the Wilcoxon test (p < 0.05) between the baseline and the 14-year follow-up. Resultsdescriptive statistics resulted in 91 % and 99 % cumulative survival rates for patients wearing 1 and 2 FDPs, respectively. There were no significant differences in periodontal parameters between control and test teeth. Both function and esthetic results were successful for FDPs over a 14-year follow-up period. Conclusionsthe results of this prospective clinical study confirmed the effectiveness of zirconia as a clinical option to fabricate short-span posterior FDPs.Clinical significance: within the limitations of the present prospective clinical study, zirconia-based three-unit fixed dental prostheses perform satisfactorily on long term, in posterior areas and in patients with standard biomechanical conditions.

Mechanical complications of implant-supported complete-arch restorations and impact on patient quality of life: A retrospective cohort study

Statement of problemMechanical complications (for example, fractures) in implant-supported complete-arch restorations may affect the social and professional activities of the patient. However, most studies seem to overlook patient perceptions and generally do not assess the changes in the quality of life (QoL) of patients who experience these complications. PurposeThe purpose of this retrospective cohort study was to assess the influence of technical or mechanical complications of complete-arch implant-supported prostheses on patient perception and QoL by using the Oral Health Impact Profile (OHIP)-14. Material and methodsA retrospective cohort study was formed of patients treated consecutively at a private clinic with immediately loaded complete-arch prostheses supported by a minimum of 4 implants (Replace Tapered; Nobel Biocare AB) and Multi-Unit conical abutments (Multi-Unit abutments; Nobel Biocare AB). OHIP-14 and questions regarding self-reported satisfaction were used to evaluate the influence of mechanical complications on QoL. ResultsFifty-six participants (26 men and 30 women) with a mean age of 64 ±11.1 years, and 72 restored arches were included. The mean ±standard deviation follow-up time was 52 ±26 months. The prosthetic success rate was 38.8%, and the survival rate was 100% (no failure was registered). The most common complications were abutment screw loosening (43%), chipping or fracture of the veneering material (25%), and screw loosening (21%). The OHIP-14 scores were close to zero, without differences between participants with or without mechanical complications. Overall, the participants reported that the prostheses allowed good oral hygiene (94.6%) and met their expectations (89%) and that they would repeat the treatment (87.5%) and would recommend it to others (93%). ConclusionsMinor mechanical complications such as screw loosening and chipping or fracture of the veneering material were frequent events but had no impact on the satisfaction and QoL of patients with immediately loaded complete-arch implant-supported prostheses.

A New Site Preparation Protocol That Supports Bone Quality Evaluation and Provides Predictable Implant Insertion Torque.

When preparing an implant site, clinicians often base their assessment of the bone on subjective tactile and visual cues. This assessment is used to plan the surgical procedure for site preparation, including how many drilling steps will be used. The subjective nature of bone evaluation, consequently, results in poor reproducibility and may lead to under or over preparation of the site. Recently, an unconventional site preparation protocol was developed in which the decision of which instruments to use is dictated by insertion torque of the novel site preparation instrument (OsseoShaper™, Nobel Biocare AB, Gothenburg, Sweden). The aim of this study was to quantify the correlation of the site preparation torques of the new instrument with bone density and maximum implant insertion torques. In vitro and in vivo data showed strong linear correlation between site preparation torque and density and resulted in reliable implant insertion torques, respectively. From our analysis, we conclude that this new instrument and protocol has the potential to eliminate the need for additional intraoperative bone evaluation and may reduce the risk of inadequate preparation of the site due to the ability to serve as a predictor of the final implant insertion torque.

Clinical analysis of the short-term and long-term results of the implant-supported Trefoil dental rehabilitation in Russia

Was to presents the first clinical medium-term (18 months) results of implant-supported rehabilitation using this method in Russia, with the special attention paid to the assessment of the patient's quality of life on the GOHAI scale. The authors performed a clinical and paraclinical examination of 29 patients (20 women and 9 men). The age of the patients ranged from 47 to 88 (average value - 65.45±9.7). We performed a retrospective analysis of all patients operated from June 2017 till March 2019. The patients filled in GOHAI questionnaires about their state of health and quality of life (before treatment and 6 weeks post-surgery). Patients with one or more anterior teeth present as well as fully edentulous mandibles were included in the study. The antagonist teeth could be presented as complete dentures, natural teeth, or implant-supported fixed restorations. All patients received three Trefoil implants (Nobel Biocare AB) inserted with a torque of at least 35 Ncm. The Trefoil bar (Nobel Biocare AB) was used as the framework of the Trefoil bioengineering structure. Statistical processing of the results was performed using the SPSS 23 software. The t-test for dependent samples was used to compare the results of GOHAI surveys before and after the operation and the following statistical hypotheses were suggested: H0 - the results of the GOHAI survey before the operation do not differ from the results of the GOHAI survey after the operation; H1 - GOHAI pre-op survey results are different from GOHAI post-op survey results. A comparison was made between the GOHAI results before and after surgery in male and female patients using the t-test for independent samples. 29 patients included in this (20 females and 9 males) with the mean age of 65 (range:47-88). The average time of operation (surgical operation, prosthetic stage including dental lab work) the Trefoil technique was 6.18 ± 0.87 hours. With the presence of teeth in the mandible, the operation took longer by an average of 45 minutes. Patients were followed for 15±6 months. No chipping of artificial teeth or fractures of the veneering was observed. The survival rate of restorations was 100%. The implant survival rate was 98.85%. The results of the GOHAI survey after surgery show a significant difference from the results of the pre-op survey. If we analyze the average values for the sample, it can be argued that the average result for the GOHAI survey before the operation (29.86) is significantly lower than the average one for the GOHAI survey after the operation (54.93). Preliminary medium-term results of the Trefoil concept for implant-supported rehabilitation of the mandible indicate high patient satisfaction results after 6-18 months of follow-up. It requires a further comprehensive study to obtain data with more patients and over a longer follow-up period.

Bacterial leakage and bending moments of screw-retained, composite-veneered PEEK implant crowns

Due to its elastic modulus close to bone, the high-performance material PEEK (polyetheretherketone) represents an interesting material for implant-supported dental prostheses. Besides a damping effect of masticatory forces, it might have a sealing effect against bacterial leakage of the implant-abutment interface (IAI). So far, PEEK has only been used for provisional implant crowns. Therefore, the aim of the study was the evaluation of the bacterial tightness of screw-retained PEEK crowns on titanium implants with conical IAI during masticatory simulation and subsequent bending moment testing.Ten screw-retained implant crowns in the shape of an upper central incisor consisting of a PEEK crown framework veneered with composite were connected to NobelActive RP titanium implants (4.3 × 11.5 mm, Nobel Biocare AB, Göteborg, Sweden) with a tightening torque of 15 Ncm.Prior to tightening, the interior of the implant was inoculated with a bacterial suspension of Enterococcus faecium. The specimens were overmolded with indicating agar (Kanamycin-Aesculin-Azid-Agar (KAAA), Oxoid Limited, Basingstoke United Kingdom), that turns black in contact with E. faecium. The specimens were subjected to a cyclic masticatory simulation whereby a force of 50 N cm was applied at an angle of 30° to the implant axis for 1.2 million cycles. Afterwards, the specimens were subjected to a static loading test according to ISO 14801:2007 to determine the bending moment.During masticatory simulation neither a loosening of the implant screws nor any damage to the veneer or the PEEK framework occurred. Furthermore, no bacterial leakage could be observed in any of the specimens. The average maximum bending moment was measured at 352.13 ± 48.96 N cm.Regarding masticatory forces, PEEK implant crowns seem to be applicable as definitive implant-supported restorations. Furthermore, the bacterial tightness of the IAI of screw-retained one-piece PEEK implant crowns is advantageous compared to superstructures of conventional materials. Further studies are necessary to substantiate the clinical significance of these findings.

Immediately restored full arch‐fixed prosthesis on implants placed in both healed and fresh extraction sockets after computer‐planned flapless guided surgery. A 3‐year follow‐up study

The treatment of patients by the use of immediate implant placement in post-extractive site is a challenging procedure. A 3-year clinical and radiological study of post-extractive implants placed using flapless guided surgery and immediately functioning. Thirty-two patients (23 females and 9 males), aged between 44 and 73 years (a mean age of 59.5) were treated with immediate full arch restorations and flapless implant surgery in fresh extraction and healed sites. A double-guide technique stent in conjunction with the NobelGuide system (Nobel Biocare AB, Göteborg, Sweden) was used. A total of 285 implants over 32 patients were assessed. The patients were clinically and radiologically followed for 3 years. One hundred and ninety-five implants were placed in the maxilla and 90 in the mandible. Eight patients received implants in both arches. One hundred and ninety-seven implants were placed in extraction sites (137 maxilla, 60 mandible) and 88 in healed sites (58 maxilla and 30 mandible). The overall cumulative implant survival rate (CISR) was 97.54%. Two implants failed in maxillary healed sites (CISR 96.55%), three in maxillary extraction sites (CISR 97.81%), and two in mandibular extraction sites (CISR 96.66%). No implant failed in healed mandibular sites (CSR 100%). All fixed prostheses maintained stability and good functionality during the follow-up, accounting for a cumulative prosthesis survival rate (CPSR) of 100%. The overall marginal bone level (MBL) was -0.52 mm (SD -0.18) after 6 months, -0.88 mm (SD -0.20) after 12 months, -1.05 mm (SD -0.21) after 24 months, and -1.32 mm (SD -0.41) after 36 months. Computer-guided surgery using double-template technique (DTT) shows a predictable outcome in the medium term, decreasing treatment timing and patient discomfort.

Immediately loaded implant-supported full-arches: Peri-implant status after 1–9 years in a private practice

ObjectiveEvaluate the peri-implant status on the long-term (1–9years) of patients treated with immediately-loaded full-arch prostheses in a private practice. MethodsA retrospective cohort study was carried out in patients consecutively treated with immediately loaded full-arch restorations supported with a minimum of 4 implants (Replace® Tapered, Nobel Biocare AB) and Multi-Unit conical abutments (MUA®, Nobel Biocare AB) with a follow-up of over 12months after placement of the final prosthesis. ResultsA total of 378 implants were placed in 56 patients. Forty upper and 32 lower arches were restored, and 16 patients received bimaxillary rehabilitation. The mean duration of follow-up was 50 months, and the implant and patient peri-implantitis prevalences were 14.3% and 50%, respectively. Mucositis affected 56.9% of the implants and 50% of the patients. The survival rate was 96.4% by patient, but reached 99.5% in the implant-based analysis, and the success rate was 95.5% for implants and 80.4% for patients. ConclusionsImmediately-loaded full-arch restorations have an acceptable outcome after 1–9years of follow-up. However, the incidence of peri-implant diseases is high, and further research is needed to confirm whether these may compromise the predictability of the prostheses over the long-term. Clinical significanceAfter a mean follow-up of 50months, the incidence of mucositis and peri-implantitis affected the 96.4% and 50% of patients, respectively. However, these results were reduced almost by half when the threshold of bleeding on probing and peri-implant bone loss applied was less strict.

A retro-prospective effectiveness study on 3448 implant operations at one referral clinic: A multifactorial analysis. Part I: Clinical factors associated to early implant failures.

Limited numbers of large effectiveness studies on routine dental implant treatment are available in the literature. To report retro-prospective data on prevalence of early implant failures in a large number of routine patients/operations at 1 referral clinic. A total of 2848 patients were consecutively provided with 9582 implants with an anodized surface (Nobel Biocare AB) during 3448 implant operations between 2003 and 2011. All patients were invited to a follow-up program and early implant failures up to first annual examination were consecutively identified. A logistic multivariate data analysis was performed to identify possible factors with an association to early implant failures. A total of 43, 73, and 81 implant operations were denoted as early failures depending on when cut-off time was defined, using: abutment connection, prosthesis placement, or at first year of follow-up, respectively. Five factors showed significant association to "early implant failures," where the highest risk for a failure was associated to "surgeon" (hazard ratio [HR] 5.13), followed by "not prosthetic treatment at the referral clinic" (HR 2.71). When all 5 significant factors were present, the risk for an early failure after an operation was 7.0%, and the risk decreased to 0.1% when none/lowest risk factors were present. The role of the surgeons/dentists involved in the rehabilitation of the implant patients and numbers of placed implants (degree of tooth loss) showed the strongest associations to early implant failures in the present clinic. Also increased bone resorption was associated to increased risk for implant failure.

A retro-prospective effectiveness study on 3448 implant operations at one referral clinic: A multifactorial analysis. Part II: Clinical factors associated to peri-implantitis surgery and late implant failures.

Little knowledge is available on implant treatment in large effectiveness studies in routine practice. To report retro-prospective data on prevalence of peri-implantitis surgery and late implant failures in a large number of routine patients at 1 referral clinic. Altogether 9582 implants with an anodized surface (Nobel Biocare AB) were consecutively placed between 2003 and 2011 and followed-up to end of 2015. All peri-implantitis operations and late implant failures were consecutively identified. A logistic multivariate data analysis was performed to identify association between the complications and different clinical factors. Furthermore, data on prevalence on risk for inflammation and bone loss at implants ("peri-implantitis") and surgery related to peri-implantitis was collected for another reference group of about 10000 implant patients during 3 consecutive years (2013-2015). Cumulative survival rates for implant operations without peri-implantitis surgery or implant failures were calculated to 96.4% (95% CI: 97.3-95.4) and 95.0% (95% CI: 96.0-94.1) after 10 years, respectively. Risk for "peri-implantitis surgery" showed a significant association (P < .05) to number of placed implants (hazard ratio [HR] 1.40; 95% CI: 1.24-1.59). Three factors showed significant association to risk for "late implant failures," where "treatment in lower jaw" had the highest risk; HR 2.03. "Overall implant failures" were associated to 4 significant factors where "surgeon" (HR 2.50) showed highest impact on risk. "Numbers of implants" and "bone resorption" at surgery were the 2 significant factors that were consistent for all the time periods of failures during follow-up (early/late/total). On an average 7.4% of examined patients in the reference group were denoted with highest risk group ("peri-implantitis") of which on an average 12.7% of these patients had surgery related to peri-implantitis. "The dentist" involved in the surgical and prosthetic rehabilitation of the implant patients, "number of implants" and degree of "bone resorption" seem to have most impact on overall implant complications and failures in the present patient group.

Early Complications of Immediate Loading in Edentulous Full-Arch Restorations: A Retrospective Analysis of 88 Cases.

To describe the clinical outcomes and complications related to provisional prostheses after full-arch implant-supported rehabilitation by means of an immediate loading protocol. This retrospective cohort study included patients who were consecutively treated with full-arch implant-supported restorations with a minimum of four implants (Replace Select Tapered TiUnite, Nobel Biocare AB) per arch and conical abutments (multi-unit, Nobel Biocare AB) by means of an immediate loading protocol. The surgical procedures were performed between May 2006 and June 2014 by a single oral surgeon. Demographic, surgical, and prosthetic variables were collected, and biologic and mechanical complications were registered. A total of 61 maxillae (57%) and 46 mandibles (43%) were treated in 88 patients (40 men and 48 women) with a mean age of 62.4 years. A total of 558 implants were placed, 295 in postextraction sockets. A total of 331 implants (59.3%) were placed in the maxilla and 227 (40.7%) in the mandible. Within a 9-month period, 18 prostheses (16.8%) fractured (15 maxillary and 3 mandibular); in nine of these patients the opposing dentition was a full-arch, implant-supported restoration, and in the remaining nine patients, it was natural dentition. Six (1.1%) maxillary and three (0.5%) mandibular implants failed. A high implant survival rate is expected in the short term following this immediate loading protocol. Fracture of the provisional prosthesis is a common finding, affecting 17% of patients, and is significantly more prevalent in patients with bruxism and in maxillary prostheses.

A retrospective study on 1592 consecutively performed operations in one private referral clinic. Part I: Early inflammation and early implant failures.

Few large-scale follow-up studies are reported on routine implant treatment. To report retrospective data on early inflammatory and early implant failures in a large number of routine patients at one private referral clinic. A total of 1017 patients were consecutively provided with 3082 implants with an anodized surface (Nobel Biocare AB) at 1592 implant operations between 2000 and 2011. All patients reported with mucosa inflammation and bone loss and/or implant failures to the first annual examination were identified. A logistic multivariate data analysis was performed to identify possible factors with an association to the two events. Altogether 33 patients/operations presented early inflammation (2.1% operations). "History of periodontitis" (OR 3.91; 95% CI: 1.86-8.21), "numbers of implants" (OR1.33; 95% CI:1.07-1.67 per implant), "two stage surgical technique" (OR 3.70; 95% CI: 1.75-7.85), and "lower jaw" treatment (OR 4.73; 95% CI: 2.12-10.57) increased the risk for early mucositis with bone loss (P < .05). Highest risk for early inflammation was observed for patients at an age of 50-55 years at surgery (P < .05). "Smoking habits" (OR 2.08; 95% CI: 1.06-4.10) "Immediate implant placement" (OR 2.09; 95% CI: 1.23-3.54), and "immediate grafting procedures" (OR 2.09; 95% CI: 1.04-4.19) had a significant association to early implant failures (P < .05). Furthermore, risk for an early failure decreased with 22% per year of inclusion (2000 >2011; OR 1.22; 95% CI;1.08-1.39). History of periodontitis and two-stage surgery protocols with bone grafts in the (posterior) lower jaw increased the risk for early inflammatory problems after surgery (P < .05), with the highest risk for mid-aged patients (P < .05). Preventable factors related to the patient (smoking) and experience of surgeon showed to have a significant association to early implant failures in routine clinical practice (P < .05).

Comparison of fit accuracy and torque maintenance of zirconia and titanium abutments for internal tri-channel and external-hex implant connections.

PURPOSEThis in vitro study aimed to evaluate the effect of implant connection design (external vs. internal) on the fit discrepancy and torque loss of zirconia and titanium abutments.MATERIALS AND METHODSTwo regular platform dental implants, one with external connection (Brånemark, Nobel Biocare AB) and the other with internal connection (Noble Replace, Nobel Biocare AB), were selected. Seven titanium and seven customized zirconia abutments were used for each connection design. Measurements of geometry, marginal discrepancy, and rotational freedom were done using video measuring machine. To measure the torque loss, each abutment was torqued to 35 Ncm and then opened by means of a digital torque wrench. Data were analyzed with two-way ANOVA and t-test at α=0.05 of significance.RESULTSThere were significant differences in the geometrical measurements and rotational freedom between abutments of two connection groups (P<.001). Also, the results showed significant differences between titanium abutments of internal and external connection implants in terms of rotational freedom (P<.001). Not only customized internal abutments but also customized external abutments did not have the exact geometry of prefabricated abutments (P<.001). However, neither connection type (P=.15) nor abutment material (P=.38) affected torque loss.CONCLUSIONAbutments with internal connection showed less rotational freedom. However, better marginal fit was observed in externally connected abutments. Also, customized abutments with either connection could not duplicate the exact geometry of their corresponding prefabricated abutment. However, neither abutment connection nor material affected torque loss values.

All-on-4® Treatment Concept for the Rehabilitation of the Completely Edentulous Mandible: A 7-Year Clinical and 5-Year Radiographic Retrospective Case Series with Risk Assessment for Implant Failure and Marginal Bone Level.

Studies are needed to evaluate long-term outcomes of the All-on-4® treatment concept (Nobel Biocare AB) for rehabilitation of edentulous mandibles by assessing marginal bone levels and risk indicators for implant failure. To evaluate 7-year clinical outcomes and 5-year radiographic outcomes of the All-on-4 treatment concept. This retrospective case series included patients admitted for implant rehabilitations in the mandible, who were followed for 7 years clinically and 5 years radiographically. Primary outcome measures were cumulative prosthetic and implant survival using patient as the unit of analysis (Kaplan-Meier product limit estimator). Secondary outcome measure was marginal bone level (MBL) at 5 years. Variables associated with implant failure were analyzed using the Cox proportional hazards regression model to calculate hazard ratios (HRs) with 95% confidence intervals (CIs). Binary logistic regression was used to compute odds ratio (OR) with 95% CIs for variables associated with MBL ≥2.8 mm at 5 years. A total of 324 patients (194 women, 130 men, average age = 58.9 years) were rehabilitated with 1,296 implants supporting 324 full-arch fixed immediately loaded mandibular prostheses. Sixty-four patients (19.8%) were lost to follow-up. Prosthetic survival was 323/324 (99.7%), and 14 patients lost 18 implants, with an estimated cumulative survival rate of 95.4% at 7 years. Variables associated with implant failure were smoking (HR = 5.28; 95% CI: 1.33, 20.91]) and the learning curve effect (0.69 < HR < 0.33 for more experienced levels). Mean MBL at 5 years was 1.81 mm (95% CI: 1.70, 1.92), and smoking was associated with MBL ≥2.8 mm (OR = 2.4; 95% CI: 1.02, 5.62). The high implant and prosthetic survival rates and excellent MBL outcome confirm the predictability and safety of the All-on-4 treatment concept over a longer term than previously reported.

Implant-Supported Single Crowns Replacing Congenitally Missing Maxillary Lateral Incisors: A 5-Year Follow-Up.

Knowledge of the long-term survival of single implants in cases of congenitally missing lateral incisors in the maxilla is limited. This retrospective study aimed to evaluate the 5-year survival of implants and implant-supported crowns (ISCs) and to assess the functional and aesthetic outcomes from the professional and patient perspectives. From a total of 46 patients with congenitally missing upper lateral incisors, 36 patients treated with 54 Brånemark® (Nobel Biocare AB, Göteborg, Sweden) implants and ISCs participated in the study. A clinical examination, California Dental Association (CDA) evaluation, and patient questionnaire were used to rate and compare the objective and subjective evaluations of the ISCs. The survival of implants and ISCs was 100%. The CDA ratings were satisfactory for all ISCs, with 70% being rated excellent. The patient rating was also high for the overall satisfaction item, with 21 being completely satisfied and 14 fairly satisfied. However, 12 patients wished for the replacement of their ISCs. Logistic regression analysis indicated that a less optimal embrasure fill was the most discriminating factor though not statistically significant (p = .082). One-third of the patients wished for the replacement of their ISCs. Soft tissue adaptation seems to be an important factor for overall satisfaction.

Posterior maxillary implants inserted with bicortical anchorage and placed in immediate function for partial or complete edentulous rehabilitations. A retrospective clinical study with a median follow-up of 7 years

The aim of this study was to report the outcome of posterior maxillary implants inserted with "bicortical anchorage" in medium or low-density bone and placed in immediate function for the rehabilitation of patients with partial or complete edentulism. Eighty-eight patients (32 males and 56 females, mean age = 54years; range 28-78years) were included from October 1999 to November 2008, and followed between 6months and 13years (median of 7years). A total of 124 posterior maxillary implants were inserted with bicortical anchorage (engaging the cortical plates of the maxillary crest along with that of either the sinus or nasal cavities) as follows: MkII (n = 1), MkIII (n = 6), MkIV (n = 18), and NobelSpeedy Groovy (n = 99); (Nobel Biocare AB). Implants were evaluated on the basis of survival, marginal bone levels, and complications (mechanical and biological). Eleven patients dropped out of the study (12.5%). Four implants were lost in four patients who underwent complete edentulous rehabilitations, yielding a cumulative survival rate of 94.2% after a median follow-up of 7years. The survival rate for the prostheses was 100%. The marginal bone levels were on average 1.56mm (standard deviation of 0.87mm), after 5-years of follow-up. Biological complications occurred with 17 implants in 17 patients. Mechanical complications occurred in 49/88 patients. Thirty of these 49 patients were heavy bruxers. Within the limitations of this study, fixed prosthetic rehabilitations for partial and complete edentulism supported by implants in the posterior maxilla which are inserted with bicortical anchorage and placed in immediate function is a viable concept on long-term follow-up. Nevertheless, controlling the occlusion is mandatory in order to decrease the likelihood of mechanical complications.

Influence of veneering porcelain thickness and cooling rate on residual stresses in zirconia molar crowns

ObjectiveThe aim of this study was to investigate the influence of increasing veneering porcelain thickness in clinically representative zirconia molar crowns on the residual stresses under fast and slow cooling protocols. MethodsSix veneered zirconia copings (Procera, Nobel Biocare AB, Gothenburg, Sweden) based on a mandibular molar form, were divided into 3 groups with flattened cusp heights that were 1mm, 2mm, or 3mm. Half the samples were fast cooled during final glazing; the other half were slow cooled. Vickers indentation technique was used to determine surface residual stresses. Normality distribution within each sample was done using Kolmogorov–Smirnov & Shapiro–Wilk tests, and one-way ANOVA tests used to test for significance between various cusp heights within each group. Independent t-tests used to evaluate significance between each cusp height group with regards to cooling. ResultsCompressive stresses were recorded with fast cooling, while tensile stresses with slow cooling. The highest residual compressive stresses were recorded on the fast cooled 1mm cusps which was significantly higher than the 2 and 3mm fast cooled crowns (P<0.05). There was a significant linear trend for residual stress to decrease as veneering porcelain thickness increased in the fast cooled group (P<0.05). No significant differences were found between the various cusp heights during slow cooling (P≥0.05). SignificanceCooling rate and geometric influences in a crown anatomy have substantially different effects on residual stress profiles with increasing veneering porcelain thickness compared to the basic flat plate model.

컴퓨터 보조 기반 치아 지지 서지컬 템프레이트를 이용한 상악구치부 임플란트 식립

Two patients with partial edentulous maxilla were scheduled to undergo installation of implant fixtures using a tooth-supported surgical template based on computer assisted treatment planning. After 3-dimensional (3D) computed tomographic scanning was transferred to the OnDemand3D (Cybermed Co., Seoul, Korea) software program for virtual planning, fixtures of MK III Groovy RP implant of the Br<TEX>${\aa}$</TEX>nemark System (Nobel Biocare AB Co., G<TEX>$\ddot{o}$</TEX>teborg, Sweden) was installed using the In2Guide (CyberMed Co., Seoul, Korea) tooth-supported surgical template with a Quick Guide Kit (Osstem Implant Co., Seoul, Korea) system in the posterior maxilla of each patient. Sinus floor elevation with a xenogenic bone graft procedure was also performed simultaneously in one patient. Fixture installations were completed successfully without complications, such as sinus mucosa perforation, bony bleedings, fenestrations, or others. During the last two-year follow-up period after prosthetics delivery, each implant was found to be fine with no other minor complications. The entire procedures are reported and the literatures on use of tooth-supported surgical template was reviewed.

Brånemark Novum® immediate loading rehabilitation of edentulous mandibles: 11-year retrospective study.

Short-term results indicated that the Brånemark Novum® protocol (Nobel Biocare AB, Goteborg, Sweden) allowed successful rehabilitation of mandibular edentulism with immediately loaded implants. Yet, long-term studies are lacking. The aim of the present retrospective study was to report the 11-year outcomes for patients treated according to this protocol. Four patients treated according to the Brånemark Novum protocol (Nobel Biocare AB) were followed-up to evaluate implant and prosthesis cumulative survival rate (CSR), implant stability (RFA), marginal bone loss by periapical radiographs, probing depth (PD), and possible complications. Clinical and radiographic parameters were evaluated immediately after completion of the treatment and 1, 5, and 11years after loading. The 11-year implant and prosthesis CSRs were 100%. Implant stability (RFA values) remained stable over the 11-year follow-up. Small bone resorption was found next to distal implants (median 1mm) after 11years, while central implants showed greater bone resorption (median 4.5mm). The PD (mean 3.75mm at 11years) grew together with marginal bone loss. One implant complication was detected on a central implant (crater-form bone destruction), and 10 prosthetic complications (fractures of resin or teeth), 80% of which registered on the same parafunctional patient. The 11-year results demonstrated that the Brånemark Novum protocol (Nobel Biocare AB) is a predictable technique with favorable long-term outcomes. This was a rigid protocol, which could be applied only in patients with specific anatomical characteristics of the lower jaw, but it had the merit of indicating the key factors for full-arch immediate loading rehabilitations.