Regular Diameter Implants Research Articles

Comparison of survival rate and crestal bone loss of narrow diameter dental implants versus regular dental implants: A systematic review and meta-analysis.

The aim of the present study was to establish survival rates, as well as crestal bone loss (CBL) of narrow diameter implants (NDI), compared to regular diameter implants (RDI). The current review followed the Enhancing the QUAlity and Transparency Of health Research guidelines and Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. We searched main databases (MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Cochrane Oral Health Group Trials Register) for articles addressing the focused question up to and including May 2018. Meta-analyses were conducted for CBL and survival rates. Qualitatively, three clinical studies showed comparable CBL and survival rates between NDI and RDI at follow up. Only one study showed increased CBL around NDI compared to RDI. The overall weighted mean difference (WMD) for CBL (WMD=.06, 95% confidence interval [CI]=-.38-.51, P=.76) and risk difference for survival rate (risk difference=.88, 95% CI=.22-3.50, P=.85) were not significant between the NDI and RDI groups at follow up. NDI and RDI showed comparable CBL and survival rates. However, the findings of the present study should be interpreted with caution due to significant heterogeneity and the low number of included studies. Further randomized, controlled trials should be performed in order to obtain strong conclusions.

Biomechanical analysis of different implant-abutments interfaces in different bone types: An in silico analysis

The purpose of this study was to analyze the stress distribution of bone tissue around implants with different implant-abutment interfaces: platform switching (PSW); external hexagon (EH) and Morse taper (MT) with different diameters (regular: Ø 4 mm and wide: Ø 5 mm), bone types (I–IV) and subjected to axial and oblique load conditions using three-dimensional finite element analysis (3D-FEA). Sixteen 3D models of various configurations were simulated using InVesalius, Rhinoceros 3D 4.0, and SolidWorks 2011 software, and processed using Femap 11.2 and NeiNastran 11.0 programs. Axial and oblique forces of 200 N and 100 N, respectively, applied at the occlusal surface of prostheses. Maximum principal stress values were obtained from the peri-implant cortical bone of each model. Statistical analyses were performed using ANOVA and Tukey's test for maximum principal stress values. Oblique loading showed higher tensile stress than axial loading (P < 0.001). Wide-diameter implants showed lower stress concentration rather than regular-diameter implants, regardless of both connection and bone type (P < 0.001). Under axial loading, wide-diameter EH implants with regular platforms showed more favorable stress distribution than PSW implants for axial loading (P < 0.001); however, under oblique loading, PSW implants exhibited lower stress concentrations (P < 0.001). Regular-diameter MT implants showed lower stress than EH implants (P < 0.001). Bone type IV showed higher stress in the cortical region than bone types I and II (P < 0.001), but no significant difference when compared with bone type III (P > 0.05). The conclusion drawn from this in silico is that MT implants should be considered for use in situations that preclude the placement of wide-diameter implants, particularly where bone types III and IV are concerned.

Narrow‐ and regular‐diameter implants in the posterior region of the jaws to support single crowns: A 3‐year split‐mouth randomized clinical trial

The objective of this 3-year split-mouth randomized controlled clinical study was to compare narrow-diameter implants (NDIs) to regular-diameter implants (RDIs) in the posterior region of the jaws (premolars and molars) in regards to (i) the marginal bone level (MBL) and (ii) implant and prosthesis survival and success rates. A total of 22 patients were included in the study. Each patient received at least one implant of each diameter (Ø3.3 and Ø4.1mm), placed either in the maxilla or mandible to support single crowns. A total 44 implants (22 NDIs and 22 RDIs) were placed and included in the study. Twenty-one implants were placed in the premolar, whereas 23 were placed in molar areas. Radiographic evaluations to access the MBL were performed immediately after implant placement, 1 and 3years after implant loading. Peri-implant clinical variables including probing pocket depth (PPD) and bleeding on probing (BoP) were obtained after crown delivery, 1 and 3years after loading. Furthermore, the survival and success rates of the implants and prosthesis were also evaluated. Twenty patients were able to complete the study. There was no statistically significant difference regarding MBL between groups at implant placement (p=.084), 1-year (p=.794) and 3-year (p=.598) time intervals. The mean peri-implant bone loss at 3-year follow-up was -0.58±0.39mm (95% CI: -0.751 to -0.409) and -0.53±0.46mm (95% CI: -0.731 to -0.329) for NDIs and RDIs, respectively. BoP was present at 15% and 10% of NDIs and RDIs, respectively, at 3-year follow-up. PPD >5mm was observed in 5% and 0% of the implants of NDIs and RDIs, respectively, at 3-year follow-up. At the 3-year examination, the implant success rates were in the NDIs and RDIs sites, respectively, 95% and 100%. The corresponding values for prosthesis success rates were 90% for NDIs and 95% for RDIs. The present study demonstrated that NDIs placed to support single crowns in the posterior region did not differ to RDIs in regards to MBL, implant survival, and success rates.

One-piece internal zirconia abutments for single-tooth restorations on narrow and regular diameter implants: A 5-year prospective follow-up study.

Studies have reported an increased risk for fractures of zirconia abutments compared with titanium abutments. The aim of this study was to evaluate single-tooth implant restorations with one-piece yttria-stabilized internal zirconia abutments on narrow and regular diameter implants up to 6 years after insertion. This study comprises 52 consecutively treated patients, with a median age of 19 years. In total, 59 narrow (3.3 mm) and 10 regular (4.1 mm) diameter implants were installed. Sixty-five all-ceramic crowns were cemented on implant-supported one-piece internal zirconia abutments and 4 restorations were screw-retained. Thirty-five patients with 48 implant restorations participated in the final examination and another 14 patients with 16 implant restorations were possible to reach and could be interviewed. The implant survival was 100% but the survival rate for the implant-supported ceramic restorations was lower, 87.5%. Three crowns (4.7%) were remade for different reasons. Five restorations (7.8%) were remade due to fracture of the internal one-piece zirconia abutment. Four of these fractures occurred in 3.3 mm implant abutments. Narrow diameter implants offer an opportunity to restore small single-tooth edentulous gaps. For esthetical reasons the choice of an abutment in zirconia can be favorable, but at least with the used implant system, there seems to be an increased risk for fracture. Most patients were very satisfied with the esthetics and function of their implant restorations.

Implant survival and patient satisfaction of reduced diameter implants made from a titanium-zirconium alloy: A retrospective cohort study with 550 implants in 311 patients.

The aim of the study was to evaluate implant survival of reduced-diameter implants compared to regular-diameter implants. A retrospective evaluation of 154 Straumann Bone Level Roxolid® implants (diameter 3.3mm) with SLActive®-surface in 107 patients, which were inserted between 2009 and 2010 in private practice, was performed. The mean observation period was 22.4±8.2 months. 396 Straumann SLActive® implants (4.1mm and 4.8mm) in 204 patients, with an observation period of 28.4±10.1 months served as control group. Implant survival rate, resonance frequency analysis and patient satisfaction were evaluated. The implant survival rate was 97.4% in the test vs. 98.5% in the control group. Resonance frequency analysis showed statistically significant lower values for the reduced-diameter implants. Patient satisfaction showed no significant difference between the test and the control group. Reduced-diameter implants displayed high survival rates during the period investigated and represent a convincing treatment alternative. Long-term follow-up investigations confirmed the high implant survival rates of 96.8% (after 69.7±12.3 months) in the test group and 98.5% (after 76.0±13.6 months) in the control group.

Mini-Implants, Mega Solutions: A Case Series.

Dental implants have evolved as a standard of care for replacement of missing teeth. Though this treatment modality promises a high level of patient satisfaction and success, it cannot be performed in all cases. Apart from medically compromised patients, implant use is also restricted whenever there is limited available bone volume at the edentulous site. An example includes the mandibular incisor, the maxillary lateral incisor region, and other sites with reduced interdental spacing and atrophic edentulous maxillary and mandibular ridges. Bone volume at some of these sites can be increased by suitable augmentation procedure for placement of a regular diameter implant (3.75 to 4.2 mm). But many a times such procedure cannot be undertaken either due to financial constraint, risk of subjecting the patient to additional surgical procedure, added time factor, or guarded prognosis of the grafted site. In such cases, mini-implants can be used. In this case series, mini-implants (2.5 to 3 mm) were used to replace teeth in all mouth quadrants and to retain a mandibular overdenture in a compromised case. The implants served well at all the sites with minimal bone loss and a high level of patient satisfaction.Mini-implants hold the potential to serve as an alternate to regular diameter implants in certain situations. Preferably they should be used in multiples to retain fixed dental prostheses and might serve as an efficient, low-cost solution for retaining overdentures in selected cases.

Narrow Diameter Implants Compared To Regular Diameter Implants Installed In The Posterior Region Of The Jaws-Results From One-Year Follow Up

Purpose: The aim of this prospective clinical study was to analyze marginal bone loss around Narrow Diameter Implants (NDIs) in comparison with that of Regular Diameter Implants (RDIs) installed in the posterior region of the jaws after one year of loading with single prostheses. Material and Methods: A total of 21 patients with a mean age of 57.2 years were included in the study. The patients received one implant of each diameter in the maxilla or in the mandible. Panoramic radiographs were realized immediately after prostheses installation (T0) and one year after loading (T1). Measurements were performed from implant shoulder to the first point of bone/implant contact. The differences in marginal bone change between the groups were analyzed by Student t-test for paired samples. A level of 95% of significance was adopted. Results: A total of 42 implants were installed (21 RDIs and 21 NDIs). At the end of the follow-up period (12 months of loading), implant success and survival rates of 100% were observed. The bone loss around implants at T0 was 0.41 (± 0.45) mm for NDIs and 0.47 (± 0.60) mm for RDIs and at T1 was 1.3 (± 0.3) mm for NDIs and 1.24 (± 0.3) mm for RDIs. No statistically significant differences between the groups were found (p>0.05). Conclusion: This study demonstrated that RDIs and NDIs produced similar marginal bone alterations patterns after one year of loading, regardless the implant location, indicating that NDIs may be used in the posterior region of the jaws with single unit prostheses in selected patients.

Clinical and radiographic evaluation of narrow‐ vs. regular‐diameter dental implants: a 3‐year follow‐up. A retrospective study

Narrow-diameter implants (NDIs) are used in severely resorbed mandibles. The reduced implant diameter means a reduction in the total contact surface between the implant and bone. The question arises whether the implant can be sufficiently osseointegrated to withstand loading forces. If not, marginal bone loss can result from overload. The aim of this retrospective study was to compare clinical and radiographic measurements and patient satisfaction of NDIs with those of regular-diameter implants (RDIs) placed in edentulous patients to support an overdenture via either a ball or a locator connection. Retrospectively over a 7-year period, a total 119 patients fulfilled the inclusion criteria and were selected for this study. The patients received two 3.3- or 4.1-mm-diameter standard titanium implants in the mandible to support an overdenture. At maintenance examinations after 1 and 3 years, clinical peri-implant and prosthetic conditions, marginal bone (MB) and patient satisfaction were investigated. None of the 238 implants were lost during the 3-year follow-up period. Overall MB loss was statistically higher in the NDI group when compared with the RDI group. At the site level, a greater MB loss was observed at the distal side of both implant types. Implants with a locator showed significantly greater MB loss (0.38 mm) compared with the implants with a ball attachment (0.14 mm) over the two-year evaluation period (P = 0.006). Patient satisfaction significantly favoured the NDI (8.3) and the locator attachment (8.6). The results suggest that during the first three years after implantation, NDIs were associated with more marginal bone loss compared with RDIs. Regardless of implant diameter, the locator attachment showed more marginal bone loss over time compared with the ball attachment.

Clinical response of edentulous people treated with mini dental implants in nine dental practices

To analyse implant survival, prosthetic aftercare and quality of life (QoL) after stabilisation of complete dentures with mini-implants. Many edentulous patients refuse implant therapy due to the expenses and fear of surgery. Studies on minimally invasive and low-cost mini-implants remain rare. A total of 133 participating patients from nine private practices were evaluated via patient records, questionnaires and clinical examinations. Complications, maintenance, QoL questions and the German short version of the oral health impact profile (OHIP-G14) were analysed. After 7 to 61 months, 15 of 336 maxillary implants and 11 of 402 mandibular implants had to be removed. In addition, four mandibular implants experienced fracture. The difference between the 4-year survival rates of 94.3% for the maxilla and 95.7% for the mandible was not statistically significant (p = 0.581). All original 144 overdentures remained functional. The prosthetic interventions were typically limited to repairs of acrylic base fractures (about one in five patients), changes of plastic O-rings and relining procedures. The participants showed OHIP-G14 scores (median = 2) that were comparable with those of patients with overdentures retained by conventional implants. Mini-implant survival was similar to that of regular-diameter implants. Although some prosthetic aftercare was necessary, none of the overdentures had to be replaced. Prospective studies comparing conventional and mini-implants are warranted.

A Retrospective, Multicenter Study on a Novo Wide‐Body Implant for Posterior Regions

Wide implants are recommended as "rescues" after failure to increase primary stability in extraction sockets or in poor quality bone. Consequently, inferior results compared with regular diameter implants have been reported. The purpose of this study was to evaluate retrospectively the outcome of a novo wide-body implant (Max® implant, Southern Implants®, Irene, South Africa) designed for placement in the posterior regions. In four private practices, patients with at least one Max implant were examined by two independent examiners to determine implant survival and marginal bone loss. Surgical, prosthetic, and patient-related parameters were evaluated to determine their influence on the treatment outcome. Seventy-five patients (31 male, 44 female), with a mean age of 58 years, received 93 Max implants (59 maxilla, 34 mandible) of 8 to 10 mm width. Twenty-seven implants in molar extraction sockets and two in mature bone were immediately loaded; 42 in extraction sockets and 22 in mature bone were delayed loaded. The mean follow-up was 14 months (6-34), and four implants failed (4.3%); mean bone loss after 1 year was 0.46 mm (SD 1.08; range -5.45-3.25). A total of 91.4% lost <1.5 mm of bone during the first year. The implant survival rate was 89.7% and 98.4%, respectively, for the immediate and delayed loaded implants and 95.8% and 95.7% for delayed and immediate placement. Time of placement, time of loading, surgical protocol, or prosthetic design did not affect the outcome. Within the limitations of the study, the Max implant demonstrated a survival rate of 95.7% and stable bone conditions after a year, irrespective of loading or surgical protocol. Future prospective studies are needed to evaluate the soft and hard tissue changes in time.

How successful are small‐diameter implants? A literature review

Edentulism is an important issue and will remain so due to high numbers of edentate individuals worldwide. For many years, complete dentures have been the only treatment option for this population. Implant overdentures have been shown to have many advantages over conventional complete dentures. However, although dissatisfied with their mandibular dentures, some edentate elders are reluctant to undergo even simple implant treatment due to factors such as cost and fear of surgery. To address these obstacles, this paper reports on a review of small-diameter implant (SDI) studies that were performed in the last two decades. The aim of this study is to (i) determine the survival of narrow diameter implants, (ii) determine whether survival is dependent on whether these implants are placed using a flap or flapless approach, and (ii) determine whether there is a relationship between length and implant survival in SDIs. In this review, studies were included that (i) involve implants with 3.5 mm diameter or less, (ii) have a randomized clinical trial, retrospective or prospective cohort design with human subjects, (iii) provide a follow up duration of at least 5 months following implant placement, (iv) include data on the survival rate of the implants. Forty one studies meeting the above criteria were published between 1993 and 2011 using SDIs from a variety of companies and surface characteristics with diameters of 1.8 mm to 3.5 mm and lengths of 8 mm to 18 mm. A total of 10,093 SDIs were inserted in approximately 2762 patients. Twenty-six studies involved flap reflection techniques for implant placement, six studies used a flapless technique and two studies used both techniques; in the remaining studies, the technique was not specified. Follow up duration varied from 5 months to over 9 years. The survival rate reported in all screened studies was over 90%, including eight studies in which a 100% survival rate was reported. In 22 studies, the reported survival rate ranged from 95% to 99.9%. Failure was reported most often in short SDIs (less than or equal 13 mm) (n = 88) compared to longer ones (more than 13 mm). Survival rates reported for SDI are similar to those reported for standard width implants. These survival rates did not appear to differ between studies that used flapless and flap reflection techniques. The failure rate appeared to be higher in shorter SDIs than in longer ones in the studies in which the length of the failed implants was reported. SDIs could be considered for use with fixed restorations and mandibular overdentures, since their success rate appears to be comparable to that of regular diameter implants. They might also be an efficient, low-cost solution for elders who wish to reduce problems with denture instability.

Mandibular single-implant overdentures: preliminary results of a randomised-control trial on early loading with different implant diameters and attachment systems

To determine surgical and prosthodontic outcomes of mandibular single-implant overdentures, opposing complete maxillary dentures, using a wide diameter implant and large ball attachment system compared with different regular diameter implants with standard attachment systems. Thirty-six edentulous participants (mean age 68 years, SD 9.2) were randomly assigned into three treatment groups (n=12). A single implant was placed in the mandibular midline of participants to support an overdenture using a 6-week loading protocol. The control group received Southern regular implants and standard ball attachments. One group received Southern 8-mm-wide implants and large ball attachments. Another group received Neoss regular implants and Locator attachments. Parametric and non-parametric tests of a statistical software package (SPSS) were used to determine between groups differences in marginal bone loss, implant stability, implant, and prosthodontic success (P<0.05). Implant success after 1 year was 75% for Southern regular implant (control) group; and 100% for the Southern wide and Neoss regular implant groups (P=0.038). Mean marginal bone loss at 1 year was 0.19 mm (SD 0.39) without significant differences observed. Implant stability quotient (ISQ) at baseline was significantly lower for the Southern regular (control) group than the other two groups (P=0.001; P=0.009). At 1 year, no significant difference in implant stability was observed (mean ISQ 74.6, SD 6.1). The change in implant stability from baseline to 1 year was significant for the control group (P=0.025). Prosthodontic success was comparable between the groups but the maintenance (41 events overall, mean 1.2) was greater for the Locator and the standard ball attachments. Mandibular single-implant overdentures are a successful treatment option for older edentulous adults with early loading protocol using implants of different diameters and with different attachment systems.

Primary stability measurements of single implants in the midline of the edentulous mandible for overdentures

To determine the primary stability of the Southern wide diameter (8 mm) implants, Neoss regular diameter (4 mm) implants, and Southern regular diameter (3.75 mm) implants placed in the midline of edentulous mandibles for single-implant overdentures. Variables related to host site and implant characteristics were investigated to determine their influence on the primary stability of the implants. A total of 36 implants were placed in the midline symphysis of the edentulous mandibles of 36 participants. Their primary stability was then measured using the magnetic Osstell mentor device. Analysis of variance (ANOVA) was used to compare the mean implant stability quotient (ISQ) scores with one-way ANOVA for multiple comparisons. The highest measurement (ISQ) of primary stability was for the Southern 8 mm wide diameter implants (84.8, SD 9.8), followed by the Neoss 4 mm regular diameter (82.3, SD 4.8) implants and the Southern 3.75 mm regular diameter implants (75.3, SD 8.4), respectively. The Southern 3.75 mm regular diameter implants had a significantly lower mean ISQ value than the same system 8 mm wide diameter (P=0.004) and the Neoss 4 mm regular diameter implants (P=0.03). No significant differences were observed between the 8 mm and the 4 mm diameter implants (P>0.05). Host-site variables such as age, gender, bone volume, and quality do not appear to influence the primary stability of the implants. No clear correlation was established between ISQ values and implant diameter.

Mandibular single‐implant overdentures: a review with surgical and prosthodontic perspectives of a novel approach

To review the literature on mandibular single-implant overdentures (opposing complete maxillary dentures), and present surgical and prosthodontic perspectives of a novel approach for this treatment option. An electronic search through the databases of Pubmed, Embase and Medline using the linked key words 'mandibular single implant overdentures' was performed. The search was limited to English language articles published up to August 2008. Hand searches through articles retrieved from the electronic search, peer-reviewed journals and recent conference proceedings were also conducted. A limited number of reports were identified on mandibular single-implant overdentures (opposing maxillary complete dentures). They comprised of case-series reports, short-term prospective trials and current randomized-controlled clinical trials. Different loading protocols with different implant systems have been used, but always with regular diameter implants. Specific anatomical and vascular dangers of the mandibular midline symphysis are identified including a novel surgical approach using a currently available short, wide diameter tapered implant. In addition, the prosthodontic rationale for using a larger attachment system (incorporating a platform switch) for mandibular single-implant overdentures is described. The review reveals that there is a lack of published randomized clinical trials using mandibular single-implant overdentures, opposing maxillary complete dentures. Without the evidence from randomized clinical trials, routine use of this novel approach cannot be recommended, compared with using regular diameter implants and matching attachment systems.

Clinical Outcome of Narrow Diameter Implants: A Retrospective Study of 510 Implants

Narrow diameter implants ([NDIs]; diameter <3.75 mm) are a potential solution for specific clinical situations such as reduced interradicular bone, thin alveolar crest, and replacement of teeth with small cervical diameter. NDIs have been available in clinical practice since the 1990s, but only a few studies have analyzed their clinical outcome. From November 1996 to February 2004, 237 patients were selected, and 510 NDIs were inserted. Implant diameter ranged from 3.0 to 3.5 mm, multiple implant systems were used, and 255 implants were restored immediately without loading (IRWL). No statistical differences were detected among the studied variables. Consequently, marginal bone loss (MBL) was considered an indicator of the success rate (SCR) to evaluate the effect of several host-, surgery-, and implant-related factors. A general linear model (GLM) was used to detect those variables statistically associated with MBL. Only three of 510 implants were lost (survival rate [SRR] = 99.4%), and no differences were detected among the studied variables. On the contrary, the GLM showed that delayed loading and longer (>13 mm) and larger (3.4 and 3.5 mm) NDIs reduced MBL. NDIs have a high SRR and SCR, similar to those reported in previous studies of regular diameter implants. Moreover, IRWL of NDIs is a reliable procedure, although a slightly higher bone resorption is reported compared to delayed loading. No implant fractures were detected in the present series.