Implant-supported Single Crowns Research Articles

Quantitative analysis of occlusal changes in posterior partial fixed implant supported prostheses

Objective To analyze changes in occlusal force distribution and occlusal contact in posterior partial fixed implant-supported prostheses over time, and to provide reference for the precise occlusion design, adjustment and maintenance of implant prostheses. Methods According to certain inclusion and exclusion criteria, patients were recruited from partially edentulous patients who had received implant-supported single crown or fixed bridge in the posterior region. The patients were collected since the implant prostheses settling and scheduled for the routine examination of implant prostheses and the occlusal examinations of complete dentition after 2 weeks, 3, 6, and 12 months. Occlusal examinations were taken with the articulating papers and T-Scan III (Tekscan, South Boston, USA), which could check and measure the occlusal contact condition of complete dentition. The occlusion time and relative occlusal forces of implant prostheses, mesial adjacent teeth and control teeth were recorded at the same time. Results Thirty-seven posterior partial fixed implant prostheses in 33 patients (17 women and 16 men, aged 24-70 years) were followed up for 3-12 months (average 8.3 months). At baseline, the relative occlusal forces of implant prostheses were significantly lower than those of the corresponding control teeth (P 0.05). Conclusion Light contact and time-delayed occlusion of posterior implant prostheses changes significantly in the first three months after settling implant prostheses. These changes mainly include the advance of the time point of the implant prosthesis to start the occlusion contact, and the increase of the occlusal force of the implant prosthesis. The occlusion of posterior implant prostheses should be carefully monitored at end of the third month follow-up clinically.

Long-term performance of implant-supported metal–ceramic and all-ceramic single crowns

PurposeTo evaluate failure rates and incidence of chipping for metal–ceramic and all-ceramic implant-supported single crowns (SCs). MethodsSix hundred and fifty-two implant-supported SCs placed in 404 patients (mean age: 57.8 years; 193 male; mean SCs per patient: 1.6) were evaluated up to 12.8 years. The frameworks of the SCs were made from Au alloys (n = 319), CoCr (n = 37), zirconia (n = 286), or lithium disilicate (n = 10). Full-coverage ceramic veneers were placed on 319 Au SCs, 34 CoCr SCs, and 92 zirconia SCs. One hundred and fifty-two monolithic zirconia SCs were not veneered. A partial veneer was placed on the buccal surface only of a further 42 zirconia SCs. ResultsA total of 26 failures were caused by loss of implants (n = 6), ceramic fractures and chipping (n = 15), loosening of the abutment (n = 4), or swallowing of a de-cemented SC (n = 1). Kaplan–Meier analysis revealed a probability of survival of 96% after five years and 92% after 10 years. A greater incidence of failure was observed for lithium disilicate and zirconia SCs than for metal–ceramic SCs (p < .05). Separate analysis of the most frequent complication, chipping (n = 61), revealed that zirconia and lithium disilicate frameworks were significant risk factors for chipping (p < 0.05). Furthermore, a significantly greater incidence of chipping was observed for SCs with full-coverage veneers than for monolithic zirconia SCs and for SCs with partial veneers (p < .05). ConclusionAvoidance of full-coverage veneers significantly improves the clinical performance of implant-supported crowns, primarily reduces the incidence of chipping.

Small trial suggests that patients receiving a single implant-supported crown in the anterior maxilla who receive provisional crowns have better soft-tissue esthetic outcomes than do those who do not

Furze D, Byrne A, Alam S, Brägger U, Wismeijer D, Wittneben JG. Influence of the fixed implant-supported provisional phase on the esthetic final outcome of implant-supported crowns: 3-year results of a randomized controlled clinical trial [published online ahead of print June 7, 2019]. Clin Implant Dent Relat Res. https://doi.org/10.1111/cid.12796.

Impact of 0.5 mm vs 1.5 mm subcrestal implant placement on marginal bone loss and aesthetics ‐ 3‐year results of a multicenter RCT

Background Among the legends circulating in implant dentistry there is the belief that aesthetics can be improved by placing implants in a subcrestal position.In literature, there are only a few RCT evaluating the differences between crestal and subcrestal placement and their main outcome is limited to short term bone loss.The influence of implant depth in subcrestal placement on the mid-long term esthetic and biological outcomes remains poorly investigated, especially in conical connection implant. Aim/Hypothesis To evaluate if the placement of single dental implants either 0.5 or 1.5 mm subcrestally in healed bone crests has an impact on long term esthetic and biological outcomes. Material and Methods Sixty partially edentulous patients requiring two single implant-supported crowns were recruited from six centres. According to a split-mouth design , the two sites were randomly allocated either to 0.5 mm or 1.5 mm subcrestal implant placement. During the healing period of 3 months, surgical sites in aesthetic areas were closed while a one-stage approach with transgingival healing screw was followed in non-aesthetic areas . Provisional acrylic crowns were delivered and were replaced after 2 months by definitive metal-ceramic crowns. Patients were followed to 3 years after loading. Outcome measures were- crown and implant failures, complications, aesthetics assessed using the pink esthetic score (PES), peri-implant marginal bone level changes, and patient preference, recorded by blinded assessors. Results At delivery of definitive crowns, 2 months after loading, the mean pink aesthetic score was 11.2 ± 1.9 and 11.1 ± 1.5 for the 0.5 and 1.5 mm group, respectively. At 3 years after loading, the mean pink aesthetic score was 12 ± 1.9 and 12.2 ± 1.8 for the 0.5 and 1.5 mm group, respectively. There were no statistically significant differences between the two groups at 2 months (P = 0.626), at 1 year (P = 0.920) or at 3 years (P = 0.296). Three years after loading, patients of the 0.5 mm group lost on average 0.34 ± 0.87 mm and those of the 1.5 mm group 0.19 ± 0.54 mm, the difference being statistically significant (difference = 0.15 mm; 95% CI 0.00 to 0.30; P = 0.046). The implant placement was not reflected in patient preference. There were no differences in outcomes among centres. Conclusion and clinical implications Both surgical protocols resulted in very high esthetic outcome (PES > 12) and minimal bone resorption (<0.5 mm) after 3 years. A slightly lower bone resorption was measured with 1.5 mm subcrestal placement compared to 0.5 mm, with no impact on the esthetic score. This tends to show that deeper implant placement might be beneficial only regarding bone stability, which will be confirmed after 5 years of follow-up.

Una evaluación retrospectiva multicéntrica de restauraciones monolíticas de circonio en dientes posteriores e implantes

Objective: the purpose of this multicenter retrospective study was to report on survival, success, and complication rates in monolithic zirconia restorations on teeth and implants. Materials and Methods: data on 671 monolithic zirconia restorations was collected by five prosthodontists from three different specialty practice centers, including a dental school and two private practice centers. Restorations included single crowns and multiple-unit fixed dental prostheses on teeth and implants in the posterior area (premolar and molars). Follow-up time was up to 62 months. Results: mean follow-up time was 28.1±12.9 months. A total of 671 units, 534 single crowns, and 137 multi-unit restorations. Cumulative survival and success rates at 5 years were 97.4%, and 93.8% respectively. Complications presented in 11 restorations out of 671 and included: decementation, abutment screw loosening, restoration crack, restoration fracture, and tooth fracture. No significant differences were observed between tooth-supported and implant-supported restoration (p=0.42), single crowns and multiple-unit restorations (p=0.07), bruxers and non-bruxers (p=0.57). Patients with group function occlusal scheme had significantly less survival rates (p=0.001). Conclusion: the use of monolithic zirconia for restorations on the posterior teeth and implants seems to be promising as it provides a durable solution with a low rate of complications.

Retrospective clinical evaluation of implant-supported single crowns: Mean follow-up of 15years.

To retrospectively assess the clinical outcomes of implant-supported single crowns and the supporting implants. This retrospective study included all patients treated with implant-supported single crowns at one specialist clinic. Implant and prosthesis failure, and mechanical/technical complications (ceramic fracture/chipping; crown loss of retention/mobility; crown failure/fracture; loosening/loss/fracture of prosthetic screw; and implant failure/fracture) were the outcomes analyzed. Any condition/situation that led to the removal/replacement of crowns was considered prosthesis failure. A total of 438 patients with 567 crowns were included. Mean±SD follow-up of 183.4±69.3months. A total of 37 implants (6.5%) and 54 crowns (9.5%) failed. If only technical problems were considered, the crown failure rate decreased to 4.1% (23/567). Most common reasons for crown failure: esthetic issue (n=12), crown constantly mobile (n=9), change to another type of prosthesis together with other implants (n=8), crown fracture (n=7), and crown in infraposition in comparison with adjacent teeth (n=7). The odds of crown failure were shown to be statistically significantly higher for the following factors: younger patients, maxillary crowns, and screw-retained crowns. Loose prosthetic screw was much more prevalent in screw-retained than in cemented crowns. Ceramic fracture/chipping was more prevalent in screw-retained crowns, maxillae, females. Crown fracture was more prevalent in ceramic crowns, screw-retained crowns, maxillae, posterior region, females. However, these differences were statistically significant only for crown fractures in females. The odds of crown failure were significant for some factors, but one must keep in mind that non-technical complications are as common as technical ones as reasons for the replacement of implant-supported single crowns.

Analyzing the occlusion variation of single posterior implant–supported fixed prostheses by using the T-scan system: A prospective 3-year follow-up study

Statement of problemOsseointegrated implants can be prone to occlusal overloading because of the absence of the periodontal ligament and limited tactile sensitivity. However, current scientific evidence of the occlusion variation of implant-supported fixed prostheses is lacking. PurposeThe purpose of this clinical study was to analyze changes in occlusal force distribution and occlusal contact in single posterior partial fixed implant–supported prostheses over time. Material and methodsPartially edentulous patients who had received implant-supported single crowns in the posterior region between December 2012 and December 2013 were enrolled. The participants underwent occlusal examinations by using the T-Scan III system at 0.5, 3, 6, 12, 24, and 36 months after implant prosthesis delivery. The relative occlusal forces (ROFs) of implant prostheses, mesial adjacent teeth, and control natural teeth were recorded, and implant prosthesis occlusion time ratios were calculated. The paired t test was used to compare the implant prosthesis occlusion time ratios and ROFs of implant prostheses at 2 different times as a self-control. The differences in ROFs between implant prostheses and control teeth in the same participant at the same time were also analyzed by using a paired t test. The Pearson correlation coefficient was used to analyze the statistical correlation between implant prosthesis occlusal force and the implant prosthesis occlusion time ratio (α=.05). ResultsThirty-seven posterior partial fixed implant–supported prostheses in 33 participants (18 women and 15 men aged 23.9 to 70 years) were followed up for 3 to 36 months (mean: 31.4 months). The ROFs of implant prostheses increased significantly (P<.05) from 2 weeks (7.46 ±4.21%) to 3 months (9.87 ±6.79%), whereas those of control natural teeth decreased significantly (P<.05) from 13.78 ±6.00% to 11.43 ±5.47%. The ROFs of implant prostheses continued to increase from 6 to 12 months and from 12 to 24 months, with significant differences (P<.05). However, they were statistically similar to those of control natural teeth at 6, 12, 24, and 36 months after restoration. Implant prosthesis occlusion time ratios also increased significantly between 2 weeks and 3 months and between 3 and 6 months (P<.05). No significant differences were found between the other time points (P>.05). ConclusionsThe occlusal force and occlusal contact time of implant prostheses changed significantly with time.

Effects of different loading protocols on the bone remodeling volume of immediate maxillary single implants: A 2- to 3-year follow-up.

The purpose of this study was to assess the effect of different loading protocols (immediate or delayed) on bone volume remodeling of an immediate implant-supported single crown in the maxilla with a follow-up from 2 to 3 years. Patients presenting a failing tooth have been rehabilitated with implant-supported single crowns. Data of patients with a survey from 2 to 3 years after baseline surgery were retrospectively acquired. One implant per patient was randomly selected during data analysis and assigned to one of two predictor groups: the loading protocol, 9 immediate vs 13 delayed loading; and tooth position, 9 incisors vs 9 canines. Cumulative survival rates were recorded; loss of crestal bone volume was assessed with cone beam computed tomography (CBCT) by means of software that superimposed the preoperative and postoperative CBCT scan data (Matrix Laboratory) and by destascan software. Twenty-two patients were enrolled. No postoperative complications or implant failures were recorded. Bone volume loss from the 2- to 3-year follow-up period ranged between 19.1% and 22.0%, without significant differences between the two loading protocols. Irrespective of the tooth site, intragroup analyses revealed the presence of significant differences between preoperative and postoperative time evaluations for all the analyzed groups and subgroups. Volumes at baseline (ranging between 0.546 cc and 0.553 cc) recorded significant loss of approximately 110 mm3 (P values ≤ .0001) for both loading protocols. The volume at the postoperative evaluation ranged between 0.428 cc and 0.442 cc. Considering tooth site in the analysis, the subgroups showed similar behaviors at the crestal bone level. However, bone loss at the apex of the implant appeared to be lower for incisors than canines. This study attested that the loss of crestal bone around an immediate implant-supported single crown depended on neither the loading protocol nor the tooth site.

Clinical performance of tooth- or implant-supported veneered zirconia single crowns: 42-month results.

The objective of this clinical study was to compare and assess the clinical performance of tooth-supported and implant-supported zirconia single crowns with sintered veneering caps. In this prospective study, 118 patients with a total of 220 single crowns placed on 106 teeth (69 vital teeth, 37 endodontically treated teeth) and 114 implants in molar and premolar regions were examined during a mean observation period of 42months. The restorations were evaluated for technical failures such as veneering porcelain fractures (chipping), surface quality, marginal fit, and the interface quality of the coping and sintered veneering. The soft tissue status was assessed using the modified Silness and Löe's plaque and gingival index (mPI) and the modified Muhlemann sulcus bleeding index (mSBI). Tooth-supported crowns were checked for secondary caries and hypersensitivity during the follow-up period. Recalls were performed every 6months. The 3-year Kaplan-Meier success probability was 98.2% and 100% for implant- and tooth-supported crowns, respectively. A significant difference could be detected between the implant-supported and tooth-supported zirconia single crowns, in terms of their chipping rate (p = 0.039). Veneering material fractures were recorded on two implant-supported restorations (1.8%). No veneering fractures occurred on tooth-supported single crowns. The plaque and gingival index and sulcus bleeding index showed stable and healthy soft peri-implant and periodontal tissues. Neither loss of vitality nor secondary caries occurred on tooth-supported crowns. Zirconia-based single crowns with a sintered veneering cap showed promising clinical results on both tooth and implant abutments; however, the dental implants were more prone to complications. In terms of clinical significance, high-strength ceramic with a sintered veneering cap can be recommended for prosthetic treatment of both tooth- and implant-supported single crowns in molar regions. This study provides valuable information for further application of all-ceramic restorations.

Clinical and radiographic peri-implant health status around narrow diameter implant-supported single and splinted crowns.

Studies assessing and comparing clinical and radiographic peri-implant status around narrow diameter implant-supported single crowns (NDISCs) and splinted crowns (NDISPs) are scarce. The aim of this retrospective study was to estimate and compare complication rates, patient satisfaction, peri-implant status and peri-implant bone loss (PBL) of NDISCs and NDISPs. Patients receiving narrow diameter implants (NDIs) in the posterior mandible were assessed. Technical complication and patient satisfaction were recorded. Clinical peri-implant plaque index (PI), bleeding on probing (BoP), probing depth (PD) and PBL were assessed. Technical complications and patient satisfaction were recorded. Log-rank test was computed to evaluate the influence of prostheses type and NDIs location on technical complications. P-value less than 0.05 was regarded as significant. Seventy-eight patients (43 male and 35 females) agreed to follow up. The mean follow-up duration of the patients was 3.6 years. A total of 102 (43 NDISCs and 59 NDISPs) NDIs with moderately rough surfaces were included. No significant differences in PI, BoP, or PD were observed between NDISCs and NDISPs. The average PBL score was 1.17 (range: 0.03-4.15) at implant level and 1.14 (range: 0.03-4.14) at patient level. Seven implants and three patients showed peri-implantitis. The rates of technical complication of single crowns were significantly higher than those of splinted crowns (P = 0.036). PBL was significantly higher in molar sites than those in premolar sites (P = 0.041). A total of 67 patients (85.9%) were satisfied with the esthetics of the crowns, while a total of 59 patients (75.6%) were satisfied with the function of the crowns. NDISCs and NDISPs offer high patient satisfaction and tolerable complication rates. Peri-implant conditions and peri-implant bone levels were comparable around NDISCs and NDISPs. However, bone loss of implants was higher in molar sites than those implants in premolar sites.

Residents' journal review

Residents' journal review

Clinical Efficiency and Patient Preference of Immediate Digital Impression after Implant Placement for Single Implant-Supported Crown.

To evaluate the time efficiency and patient preference of three impression techniques by comparing immediate digital impression performed directly after implantation with regular digital impression and conventional implant impression performed 3 months after implantation. Twenty consecutive patients with a missing single molar or premolar who received implant treatment were recruited into this prospective self-controlled clinical trial. Three different impression techniques were performed after implant surgery on all the participants: An intraoral scanning (IOS) impression performed immediately after implant placement (immediate digital impression) was compared with a regular digital impression and a classic polyether impression (conventional implant impression) performed 3 months after implant surgery. The operating time of each impression technique was recorded. Patients were asked to complete a visual analogue scale (VAS) questionnaire on their perception of the three techniques to describe their satisfaction and preference. Statistical analyses were performed with the Wilcoxon signed rank test. The clinical time of the immediate digital impression (10.97 ± 2.1 min) was significantly shorter than that of the conventional implant impression (14.45 ± 3.0 min) (P < 0.05). The mean time of the immediate digital impression (10.97 ± 2.1 min) was statistically the same as that of the regular digital impression (10.23 ± 2.7 min) (P > 0.05). Participants' subjective evaluation indicated higher satisfaction with the immediate digital impression than with the regular digital impression and the conventional implant impression. The immediate digital impression was more efficient than the conventional implant impression and had the same efficiency as the regular digital impression. Among the three impression techniques, the participants showed higher satisfaction with the immediate digital impression.

Esthetic evaluation of implant-supported single crowns: a comparison of objective and patient-reported outcomes

BackgroundThis study investigated objective and patient-reported esthetic outcomes and their correlation for single-tooth implant restorations in the maxillary anterior region.MethodsNineteen patients were included. Gingival biotypes and smile lines were evaluated. Esthetic evaluation was performed according to the pink and white esthetic scores (PES and WES). Patients rated their satisfaction regarding the implant treatment using a subjective outcome questionnaire and a 10-cm visual analogue scale (VAS).ResultsThe mean PES and WES were 10.7 (range 5–13, SD ± 2.24) and 8.6 (range 8–10, SD ± 0.60), respectively. The overall mean VAS was 8.54 ± 0.36 (range 3.8–9.8). No significant correlation was found between VAS and PES or WES (p = 0.475, p = 0.984, respectively). PES and WES scores for gingival biotypes failed to show any statistically significant difference (p = 0.701, p = 0.831). There was a significant negative correlation between the smile line and VAS; indicating that patients with lower smile lines expressed higher patient satisfaction (p = .001).ConclusionsProfessionally reported esthetic outcomes (PES and WES results) may not correlate with patient-reported outcomes. Smile line is a significant factor in patient satisfaction, which should be evaluated thoroughly prior to implant placement in the anterior maxilla.

The clinical performance of all-ceramic implant-supported single crowns: A systematic review and meta-analysis.

This review aimed at evaluating the survival and technical complication rates of all-ceramic implant-supported single crowns (SC). Three electronic databases were searched for clinical studies conducted at ≥15 patients examining implant-supported all-ceramic SCs over ≥12months. Survival rates of implants and restorations plus technical complication rates of SCs were calculated and tested for statistical correlation with confounding variables. Statistical analysis was performed using a negative binomial distribution model to calculate 5- and 10-year survival and complication estimates. Forty-one included studies reported on implant-supported SCs made of veneered and monolithic high-strength oxide ceramics, monolithic, and veneered glass-based ceramics and of a monolithic resin-nano-ceramic (RNC). Survival estimates for SCs of 93% (95% CI: 86.6%-96.4%) after 5years and 94.4% (95% CI: 91.1%-96.5%) after 10years were calculated, corresponding values for implant survival were 95.3% (95% CI: 90.6%-97.7%) and 96.2% (95% CI: 95.1%-97.1%). Technical complication rates after 5/10years were as follows: chipping 9.0% (95% CI: 5.4%-14.8%)/2.7% (95% CI: 2.1%-3.5%), framework fractures 1.9% (95% CI: 0.7%-4.9%)/1.2% (95% CI: 1%-1.5%), screw loosening 3.6% (95% CI: 1.6%-8.4%)/5.2% (95% CI: 3.6%-7.5%), and decementations with 1.1% (95% CI: 0.4%-2.8%) after 5years. Some confounding variables influenced the above-mentioned estimates significantly. All-ceramic implant-supported SCs showed-with the exception of a RNC material-high survival rates. However, failures and technical complications occurred which have to be considered when informing patients on the treatment with implant-supported all-ceramic SCs.

A systematic review of the survival and complication rates of zirconia-ceramic and metal-ceramic single crowns.

The aim of the present systematic review was to analyze the survival and complication rates of zirconia-based and metal-ceramic implant-supported single crowns (SCs). An electronic MEDLINE search complemented by manual searching was conducted to identify randomized controlled clinical trials, prospective cohort and retrospective case series on implant-supported SCs with a mean follow-up time of at least 3years. Patients had to have been clinically examined at the follow-up visit. Assessment of the identified studies and data extraction was performed independently by two reviewers. Failure and complication rates were analyzed using robust Poisson's regression models to obtain summary estimates of 5-year proportions. The search provided 5,263 titles and 455 abstracts, full-text analysis was performed for 240 articles, resulting in 35 included studies on implant-supported crowns. Meta-analysis revealed an estimated 5-year survival rate of 98.3% (95% CI: 96.8-99.1) for metal-ceramic implant supported SCs (n=4,363) compared to 97.6% (95% CI: 94.3-99.0) for zirconia implant supported SCs (n=912). About 86.7% (95% CI: 80.7-91.0) of the metal-ceramic SCs (n=1,300) experienced no biological/technical complications over the entire observation period. The corresponding rate for zirconia SCs (n=76) was 83.8% (95% CI: 61.6-93.8). The biologic outcomes of the two types of crowns were similar; yet, zirconia SCs exhibited less aesthetic complications than metal-ceramics. The 5-year incidence of chipping of the veneering ceramic was similar between the material groups (2.9% metal-ceramic, 2.8% zirconia-ceramic). Significantly (p=0.001), more zirconia-ceramic implant SCs failed due to material fractures (2.1% vs. 0.2% metal-ceramic implant SCs). No studies on newer types of monolithic zirconia SCs fulfilled the simple inclusion criteria of 3years follow-up time and clinical examination of the present systematic review. Zirconia-ceramic implant-supported SCs are a valid treatment alternative to metal-ceramic SCs, with similar incidence of biological complications and less aesthetic problems. The amount of ceramic chipping was similar between the material groups; yet, significantly more zirconia crowns failed due to material fractures.

A systematic review of the influence of the implant-abutment connection on the clinical outcomes of ceramic and metal implant abutments supporting fixed implant reconstructions.

The objective of this systematic review was to assess the influence of implant-abutment connection and abutment material on the outcome of implant-supported single crowns (SCs) and fixed dental prostheses (FDPs). An electronic Medline search complemented by manual searching was conducted to identify randomized controlled clinical trials, prospective and retrospective studies with a mean follow-up time of at least 3years. Patients had to have been examined clinically at the follow-up visit. Failure and complication rates were analyzed using robust Poisson regression, and comparisons were made with multivariable Poisson regression models. The search provided 1511 titles and 177 abstracts. Full-text analysis was performed for 147 articles resulting in 60 studies meeting the inclusion criteria. Meta-analysis of these studies indicated an estimated 5-year survival rate of 97.6% for SCs and 97.0% for FDPs supported by implants with internal implant-abutment connection and 95.7% for SCs and 95.8% for FDPs supported by implants with external connection. The 5-year abutment failure rate ranged from 0.7% to 2.8% for different connections with no differences between the types of connections. The total number of complications was similar between the two connections, yet, at external connections, abutment or occlusal screw loosening was more predominant. Ceramic abutments, both internally and externally connected, demonstrated a significantly higher incidence of abutment fractures compared with metal abutments. For implant-supported SCs, both metal and ceramic abutments with internal and external connections exhibited high survival rates. Moreover, implant-supported FDPs with metal abutments with internal and external connections for also showed high survival rates.

Short Dental Implants (6 mm) Versus Standard Dental Implants (10 mm) Supporting Single Crowns in the Posterior Maxilla and/or Mandible: 2-Year Results from a Prospective Cohort Comparative Trial.

ABSTRACTObjectivesThe purpose of present study was to compare short (6 mm) with longer implants with the same surface use in the posterior maxilla and/or mandible.Material and MethodsA total of 110 implants of 6 or 10 mm in length were placed with an internal hex (n = 60) and with a conical connection (n = 50) but the same material, surface and design, supporting single crowns in the posterior maxilla and/or mandible. Outcomes measured were implant survival and marginal bone level changes up to 24 months after loading.ResultsFinal group consisted of 105 implants: 6 mm (n = 58) and 10 mm (n = 47). Success rate after 24 months was similar between treatment groups (98.3% vs. 100%; P = 0.361). Failure rates of the short implants in mandible (1/18, 5.6%) and in maxilla (0/40, 0%) were also not significantly different (P = 0.133). Success rate after 2 years was similar between internal hex vs. conical connection implants (100% vs. 97.7%; P = 0.233). Subjects lost statistically significant marginal peri-implant bone in both groups, but without differences (6 mm group: 0.38 mm [95% CI = 0.09 to 0.67] vs. 10 mm group: 0.43 mm [95% CI = 0.15 to 0.61]; P = 0.465 at 24 months), in relation also to type of implant (internal hex vs. conical, P = 0.428 at 24 months) or operator (P = 0.875 at 24 months).ConclusionsShort implants may be successful in the posterior areas during the first 24 months of loading, with similar outcomes to 10 mm long implants, supporting their use as a valid option in selected cases. However, larger and longer follow-ups of 5 years or more are needed.

Treatment of missing maxillary lateral incisors: a clinical and aesthetic evaluation.

The aim of this study was to evaluate whether implant therapy or orthodontic space closure was the best treatment option for patients with missing maxillary lateral incisors. The implant group (I group) consisted of 22 patients aged <26 years who had one or both maxillary lateral incisors substituted by a single implant-supported crown. The space-closure group (SC group) consisted of patients matched with I group patients based on diagnosis, gender, and number. Examinations were performed by one examiner and occurred at least 5 years after the prosthetic therapy or orthodontic treatment was finished. Clinical examination of the 44 patients involved assessing the aesthetics and gingival conditions of the implant-supported crown and the replacement canine, the occlusal morphology and the extraoral characteristics. Both the patient and examiner answered a question about their satisfaction with the aesthetic result. Of the 12 variables analysed by the examiner, one variable was significantly improved in the I group and five variables were improved in the SC group. There were no significant differences between the treatment groups for the remaining six variables. Gingival colour and crown length were better in the SC group, and crown colour was better in the I group. There were no significant differences between the groups with regards to the patient's and examiner's overall aesthetic satisfaction of the maxillary anterior teeth or between the patient's and examiner's opinion. If both treatment alternatives are available, space closure is preferable.

Immediate Loading of Implant-Supported Single Crowns after Conventional and Ultrasonic Implant Site Preparation: A Multicenter Randomized Controlled Clinical Trial.

Aim To compare implant survival rate and marginal bone loss (MBL) of immediately loaded single implants inserted by using ultrasonic implant site preparation (UISP) (test) and conventional rotary instrumentation (control). Methods Two single implants were inserted for each patient: after randomization, test site was prepared by using an ultrasonic device (Piezosurgery Touch, Mectron, Italy) and control site was prepared by using the drills of the selected implant system (Premium AZT, Sweden & Martina, Italy), until reaching a final diameter of 3 mm in both groups. Identical implants (3.8x11.5 mm) were inserted in all sites at crestal level. Impressions were taken and screwed resin single crowns with platform-switched provisional abutments were delivered with 48 hours. Periapical radiographs were taken at provisional crown insertion (T0), 6 months (T1) and one year (T2) after prosthetic loading to measure MBL. All data were tested for normality and subsequently analyzed by paired samples t-test and forward multiple linear regression. Results Forty-eight patients were treated in six centers with the insertion of ninety-six implants (48 test; 48 control). Four implants in four patients failed within the first six months of healing (two in test group; two in control group; no difference between groups). Forty patients (age 60.1±10.7 years; 22 female, 18 male) were included in the final analysis. Mean MBL after six months of loading was 1.39±1.03 mm in the test group and 1.42±1.16 mm in the control group (p>0.05) and after one year was 1.92±1.14 mm and 2.14±1.55 mm in test and control, respectively (p>0.05). Conclusions No differences in survival rate and MBL were demonstrated between UISP and conventional site preparation with rotary instruments in immediately loaded dental implants: UISP, with its characteristics of enhanced surgical control and safety in proximity of delicate structures, may be used as a reliable alternative to the traditional drilling systems.

The effect of surface texture on the retention of single implant-supported crowns cemented on wide-platform abutments

OBJECTIVE: This in vitro study evaluated the retention of copings cemented with a provisional cement and a permanent cement on wide-platform short abutments with different surface texture.METHODS: Two wide-platform abutments (height 4.0 mm) with machined (original) or modified surface (air-blasted with 50-µm aluminum oxide) were connected to two implant replicas under torque of 35 N.cm. Ten copings were cast in Cr-Co alloy from calcinable cylinders. Each coping was luted on the abutment under an axial force of 5 kg for 10 min, and the specimen was stored in a humid environment at 37°C for 20 h. After mechanical cycling simulating masticatory fatigue for 7 days (5754 cycles, 60 cycles/min, 200 N, 37°C), the specimens were subjected to a uniaxial tensile test at 0.5 cm/min, and the maximum retention strength (N) was recorded. After testing, the surfaces were cleaned, and the procedures were repeated for each coping in the experimental group. Data were analyzed by Student t test for paired samples. RESULTS: For the temporary cement, the mean retention (SD) was 36.1 (10.7) N for the machined surface and 49.6 (2.7) N for the blasted surface (P=0.004) (37% increase). For the zinc phosphate cement, the values were 292.0 (89.8) N and 440.6 (48.1) N, (P&lt;0.001) (42% increase).CONCLUSION: The results suggest that the air-blasting of short and wide abutments increases the retention of the cast coping cemented with temporary or permanent cement.