One-year clinical outcomes of locking taper Equator attachments retaining mandibular overdentures to narrow diameter implants

Patient-reported outcome measures and clinical performance of implant-retained mandibular overdentures with stud and ball attachments: A systematic review and meta-analysis

STATEMENT OF PROBLEM

Evidence regarding the retention system for a mandibular overdenture is important for treatment planning. However, the clinical performance of stud and ball attachments for mandibular overdenture retainers is unclear.

PURPOSE

The purpose of this systematic review and meta-analysis was to compare the clinical performance and self-reported patient outcomes of ball and stud attachments as mandibular overdenture retainers.

MATERIAL AND METHODS

Randomized (RCTs) and nonrandomized (N-RCTs) controlled clinical trials were selected based on the eligibility criteria. The risk of bias was assessed by using the Cochrane Collaboration Tools, and the certainty of the evidence (COE) by using the grades of recommendation, assessment, development, and evaluation (GRADE) workshop approach. Meta-analyses according to the follow-up period were performed for implant survival, prosthetic maintenance and complications, bleeding on probing (BoP), marginal bone loss (MBL), satisfaction, and oral health-related quality of life (OHRQoL).

RESULTS

Thirteen RCTs and 4 N-RCTs were included. Twelve studies presented a high risk of bias. The stud demonstrated a lower risk ratio (RR) (P<.001) for maintenance and complications concerning the need for matrix activation (RR 7.12 [2.65, 19.15]) (very low COE) and new overdentures (RR 2.47 [1.02, 5.96]) (moderate COE), ranging from 1 to 5 years of follow-up. Mean difference (MD) for MBL after 1 (MD 0.40 [0.28, 0.52]; P<.001) and 5 years (MD 0.18 [0.16, 0.20]; P<.001) was higher for ball attachments than that for stud (very low COE) attachments. Stud attachments also improved satisfaction (P<.001) when compared with ball attachments (very low COE). Implant survival rate (high COE), BoP (very low COE), and OHRQoL (low COE) were similar for the attachments.

CONCLUSIONS

Stud and ball attachments are clinically appropriate options as mandibular overdenture retainers and are capable of restoring OHRQoL. Nevertheless, the stud showed greater improvement in satisfaction and less prosthetic aftercare and MBL.

Funding assistance and global productivity in the field of implant overdentures: A bibliometric analysis of 35 years

STATEMENT OF PROBLEM

Implant overdentures have been widely used as a treatment option for edentulous patients. However, the development of implants, aside from commercial growth, requires funding assistance to determine scientific reliability and clinical applications. Nonetheless, bibliometric studies in the implant overdenture field are lacking.

PURPOSE

The purpose of this bibliometric analysis was to evaluate the prevalence of funding and its bibliometric associated parameters according to the financial assistance granted and the implant overdenture documentation over time.

MATERIAL AND METHODS

Six databases were assessed, and 12 bibliometric parameters related to the economy, geographical origin, publication details, and corresponding author metrics were recorded. An incidence rate ratio was applied by using a multiple Poisson regression model (α=.05) to assess the association between funding and each bibliometric parameter.

RESULTS

In total, 1369 studies published between 1986 and 2021 were assessed bibliometrically. The prevalence of funded studies was 34.8% (n=477). The parameter associated with the presence of funding was country income (P<.01), with those having a high and upper-middle income being more funded than those with a lower-middle and low income. Oceania and South America were the continents more frequently funded (P<.05), with Africa being the least frequent. Randomized and nonrandomized controlled trials, in vitro studies, and in silico studies were more funded (P<.001) than case reports and series. Stud and ball attachment systems were more funded (P<.01) than studies with more than 1 retention system. Funding increased over time (P<.01), and corresponding authors with a higher h-index had more studies funded (P<.05).

CONCLUSIONS

The number of funded studies on implant overdentures increased over the years. Other bibliometric parameters such as country income, continent, study design, retention system, and corresponding author h-index were associated with the frequency of funded studies published.

Immediate versus conventional loading of mandibular implant-retained overdentures: a 3-year follow-up of a randomized controlled trial

OBJECTIVES

There is a scarcity of randomized clinical trials (RCT) that report medium- and long-term results and a lack of consensus in the literature on the predictability of immediately loaded unsplinted narrow diameter implants supporting mandibular overdentures. This RCT compared the performance of conventional (CL) and immediate loading (IL) of mandibular overdentures retained by two narrow-diameter implants for 3 years.

MATERIALS AND METHODS

Patients from an RCT treated with CL or IL were invited to attend to 2- and 3-year follow-ups. Clinical, radiographic, functional, and oral health-related quality of life parameters were evaluated. Prosthetic maintenance events, biological complications, and success and survival rates were also recorded. The data were tested by multilevel mixed-effects linear regression analysis and chi-squared tests.

RESULTS

The 1-year survival rates of 90% in the CL group and 85% in the IL group were maintained as no implants were lost between 1 and 3 years. The marginal bone loss (MBL) in the IL group was significantly lower after year 3 (-0.04; p < 0.01). Significant changes were found only for the intra-group comparisons in the third year of function: (i) CL and IL presented similar progression of implant stability, MBL, and posterior bone area resorption; (ii) while CL started deteriorating of masticatory function, IL still exhibited functional evolution and (iii) oral comfort domain in the CL and pain domain in the IL were improved.

CONCLUSION

Although IL experienced the lowest MBL after 3 years, the outcomes showed that both loading protocols result in predictable medium-term rehabilitation when monitored annually.

CLINICAL RELEVANCE

It can be expected that in the third year of function, patients with immediate loading may present more complaints related to general performance even with acceptable masticatory function and self-reported improvements in oral comfort.

Effect of mandibular bone atrophy on maxillary and mandibular bone remodeling and quality of life with an implant-retained mandibular overdenture after 3 years

STATEMENT OF PROBLEM

The medium-term effect of an implant-retained mandibular overdenture on bone remodeling in the maxilla and posterior mandible of edentulous patients and the effects on quality of life have not been established.

PURPOSE

The purpose of this prospective observational clinical study was to evaluate the 3-year effects of implant-retained mandibular overdentures on oral-health-related quality of life (OHRQoL) and bone remodeling in different regions of the maxilla and mandible in participants with atrophic or nonatrophic mandibles.

MATERIAL AND METHODS

Twenty-six edentulous participants received 2 narrow-diameter implants in the anterior mandible. Mandibular bone atrophy was categorized from presurgical panoramic radiographs according to the Cawood and Howell criteria. OHRQoL was assessed by using the OHIP-EDENT questionnaire. Participants were evaluated annually for 3 years to measure the marginal bone loss and bone area of the posterior mandible, and the anterior and posterior regions of the maxilla were assessed annually through panoramic radiographs. The data were analyzed by using a mixed-effects linear regression to estimate time-dependent trends and a mixed-effect linear regression model to verify differences between groups. The Pearson correlation coefficients between bone variables and 3-year OHIP-EDENT outcomes were calculated.

RESULTS

In the third year, atrophic participants had a significantly lower marginal bone loss (0.02 mm) than nonatrophic participants (-0.39 mm) (P=.030). Differences were also found in the functional limitation (nonatrophic=1.82 ±1.75, atrophic participants=1.92 ±1.54; P=.018) and handicap domains (nonatrophic=0.36 ±0.54, atrophic participants=0.08 ±0.27; P=.003). For nonatrophic participants, comparisons between baseline and 3-year outcomes showed significant bone resorption as indicated by the area ratio in the anterior maxilla (P=.035), posterior maxilla (P=.022), and posterior mandible (P=.009). Conversely, the bone area of the anterior maxilla (P=.019) decreased in atrophic participants between baseline and year 1, while the bone area of the anterior maxilla and posterior mandible increased (P<.001) between years 1 and 3. Higher effect sizes were observed in the OHRQoL domains of the atrophic participants.

CONCLUSIONS

Bone atrophy influenced both the OHRQoL profile and bone remodeling profile in different regions of the mandible and maxilla in mandibular overdenture users. In atrophic participants, bone tissue in both jaws responded positively to overdenture use, with bone apposition after the first year and bone area preservation in the anterior maxilla, posterior mandible, and peri-implant regions after 3 years of follow-up.

Prosthetic complications and quality of life among wearers of mandibular overdenture with the Facility-Equator system

This longitudinal study aimed to assess the performance of the Facility-Equator system as mandibular overdenture (MO) retainers from a prosthetic perspective during 2 years of loading and to investigate the oral health-related quality of life (OHRQoL) and whether prosthetic events can affect the OHRQoL. Twenty-four patients (68.1 ± 7.51 years) reported their OHRQoL through the Geriatric Oral Health Assessment Index (GOHAI) and Oral Health Impact Profile (OHIP-EDENT) questionnaires before MO loading and after 1 and 2 years of usage. Prosthetic occurrences were recorded during this period. Data were analyzed using the Wilcoxon test, Mann-Whitney test, and Spearman correlation coefficients. Of the 127 prosthetic events that occurred in the first year, the most frequent events were prosthesis adjustments (16.5%), dislodgement of the Equator attachment (14.17%), and O-ring replacement (11.8%). Eighty-seven prosthetic events were recorded in the second year, the most frequent events being prosthesis adjustments (27.6%), O-ring replacement (20.7%), and recapturing the female matrix (11.5%). All domains of the GOHAI and OHIP-EDENT questionnaires exhibited a significant difference (p < 0.05) between the baseline and 1- and 2-year evaluations, except in the Social Disability and Psychological Discomfort domains (p > 0.05) of OHIP-EDENT after 1 year. Complications related to prosthetic maintenance, such as fracturing of the prosthesis, Equator dislodgement, prosthesis rebasing, and new overdenture confection, affect the OHRQoL (p < 0.05), primarily the Physical Pain and Discomfort domains, especially in the first year of MO loading.

Circumferential bone level and bone remodeling in the posterior mandible of edentulous mandibular overdenture wearers: influence of mandibular bone atrophy in a 3-year cohort study

OBJECTIVES

Evaluate circumferential bone level and morphological alterations in the posterior mandibular ridge of atrophic (AP) and non-atrophic (NAP) patients using implant-retained mandibular overdentures (MO) over 3 years.

MATERIALS AND METHODS

Twenty-six edentulous patients categorized according to mandibular atrophy (AP = 13/NAP = 13) received two narrow diameter implants (Facility, 2.9 × 10 mm) in the anterior region of mandible. The vertical and horizontal bone level was measured along with bone remodeling at 4 distances from the mental foramen in the posterior region of the mandible (L1-L4) via CBCT.

RESULTS

NAP showed significantly higher total height and medullary height in all posterior regions at 1 and 3 years (p ≤ 0.01). Cortical height and width were significantly higher (p ≤ 0.05) in this group at distances L1 and L4, respectively, in year 1. NAP shows a significantly higher % of medullary height at distances L1 (p ≤ 0.05), L2 (p ≤ 0.01), and L3 (p ≤ 0.05) after 1 year, and at all distances (p ≤ 0.05) after 3 years. Bone remodeling in the groups differed significantly (p ≤ 0.05) in terms of cortical width and % medullary width at L3.

CONCLUSION

AP and NAP showed similar vertical and horizontal bone level. Bone resorption in the posterior ridge was stabilized by MO over 3 years; however, AP are more susceptible to the long-term substitution of medullary bone by cortical bone.

CLINICAL RELEVANCE

This study is the first to longitudinally evaluate bone dimensions in atrophic and non-atrophic two-implant MO users by CBCT and revealed that MO is a predictable treatment based on the stabilization of the posterior bone resorption.

Prosthetic aftercare, mastication, and quality of life in mandibular overdenture wearers with narrow implants: A 3-year cohort study

OBJECTIVES

This cohort study investigated clinical, functional, and quality of life outcomes, along with prosthetic maintenance events in mandibular overdenture (MO) wearers for 3 years.

METHODS

Thirty MO wearers with narrow diameter implants (NDIs) and locking taper stud abutments (Facility-Equator system) were annually monitored by registering the visible plaque index (VPI), peri‑implant inflammation (PI), calculus presence (CP), probing depth (PD), bleeding on probing (BOP), secondary implant stability (ISQ), marginal bone loss (MBL), masticatory performance and dental impact in daily life (DIDL) questionnaire domains. Multilevel mixed-effects linear regression was performed to analyse changes over time. Chi-square tests were performed to analyse the relationship between the appearance of prosthetic complications and maintenance occurrences. The survival rate of patients with NDIs was calculated using the Kaplan-Meier test.

RESULTS

Twenty-six individuals attended all follow-ups, the survival rate of 83.3% in the first year was maintained, and no one implant was lost over the 3-year period. There were significant differences for PD between 1 and 3 years (p ≤ 0.01) and between 2 and 3 years for PI (p ≤ 0.01), GI (p ≤ 0.01), ISQ (p = 0.02), and MBL (p ≤ 0.01). All masticatory performance outcomes showed significant differences (p ≤.01). Prosthetic maintenance events decreased significantly over time. Appearance, general performance, and eating and chewing domains presented high effect sizes.

CONCLUSION

Continued changes were observed in the clinical parameters of MO users over the 3-year period. In addition, most functional parameters, except for particle homogenization, improved significantly over time. The positive impact on quality of life is likely related to the significant reduction in prosthetic maintenance events.

CLINICAL SIGNIFICANCE

Periodic returns to assess peri‑implant tissues and MO maintenance should be performed to ensure the success of rehabilitation to assure improvements in masticatory function and oral health-related quality of life.

Clinical performance of narrow-diameter implants with hydrophobic and hydrophilic surfaces with mandibular implant overdentures: 1-year results of a randomized clinical trial

OBJECTIVE

To compare peri-implant clinical and radiographic parameters between hydrophilic and hydrophobic narrow dental implants in patients with mandibular implant overdentures for 1 year.

MATERIALS AND METHODS

In a randomized, double-blind, split-mouth study with a 1-year follow-up, sixteen edentulous participants received two narrow-diameter implants in the anterior mandibular region with 2 types of surfaces: hydrophobic (Neoporos surface, NS) and hydrophilic (Acqua surface, AS). During the osseointegration period and after loading with mandibular implant overdentures, the outcomes monitored were (i) peri-implant health: early healing index (EHI), visible plaque index (VPI), calculus presence (CP), peri-implant inflammation (PI), probing depth (PD), and bleeding on probing (BOP); (ii) implant stability quotient (ISQ), (iii) crestal bone loss (CBL) and bone level change (BLC); and (iv) implant success and survival rates.

RESULTS

The PD in NS implants decreased by 31.78% between 15 and 30 days, while a similar reduction (-31.28%) occurred in the 3rd month in the AS group. The ISQ also decreased significantly during the 1st month in both groups: -10.95% after 7 days in the NS group and -7.46% after 15 days in the AS group. At 12 months, statistically significant differences were not observed; however, the AS surface presented 50.6% smaller CBL and 41.3% smaller BLC values. The success and survival rates were 62.5% for AS implants and 87.5% for NS implants.

CONCLUSION

Narrow-diameter implants with hydrophilic and hydrophobic surfaces loaded with mandibular implant overdentures showed no differences in peri-implant healing, stability, and peri-implant bone remodeling in the 1st year of follow-up.

Use of Narrow-Diameter Implants in Completely Edentulous Patients as a Prosthetic Option: A Systematic Review of the Literature

Objective

The objective of the present review is to assess the implant survival, marginal bone loss, and biomechanical features of narrow-diameter implants (2.5-3.5 mm) supporting or retaining full-arch fixed or removable restorations.

Materials and Methods

Three operators screened the literature (PubMed, Cochrane Library, and Google Scholar) and performed a hand search on the main journals that focus on implantology until 24 March 2019. Only articles that considered full-arch restorations supported or retained by narrow-diameter implants (2.5-3.5 mm) were considered if they have a minimum of 10 patients and a mean follow-up of at least 6 months. The outcome variables were survival of implants and marginal bone loss. The review was performed according to the PRISMA statements. Risk of bias assessment was evaluated. Failure rates were analyzed using random effect Poisson regression models to obtain the summary estimate of 5-year survival rate and marginal bone loss.

Results

A total of nine papers were finally selected, reporting a high survival rate of the implants. Eight studies focused only on the mandible while one study reported data from both mandible and maxilla. All studies reported on removable restorations; none focused on fixed rehabilitations. The estimated survival rate for 5 years of follow-up was calculated to be 92.25% for the implants. The estimated marginal bone loss after 5 years was calculated to be 1.40 mm. No study reported implant fractures.

Conclusions

With the limitations of the present study, there is evidence that 2.5-3.5 mm narrow-diameter implants retaining a removable restoration can be a successful treatment in fully edentulous patients. No data on fixed restorations was available.

Effect of macrogeometry and bone type on insertion torque, primary stability, surface topography damage and titanium release of dental implants during surgical insertion into artificial bone

This study investigated the influence of implant macrogeometry and bone type on insertion torque (IT), primary stability (ISQ), surface topography damage, and the amount of titanium (Ti) released during insertion. Forty implants with different macrogeometries (Facility - Cylindrical with spiral-shaped threads; Alvim - Tapered with buttress-shaped threads) were inserted into artificial bone types I-II and III-IV. Surface morphology was evaluated by Scanning Electron Microscope (SEM) and roughness parameters with Laser Scanning Confocal Microscopy (LSCM) before and after insertion (AI). Implant macrogeometry was characterized by LSCM. The chemical composition of bone beds was determined by SEM associated with Energy Dispersive X-Ray Spectroscopy. The amount of Ti released was analyzed with Energy Dispersive X-Ray Fluorescence. Alvim had greater IT and ISQ than Facility. Bone types I-II require higher IT of implants. Alvim also had greater internal threads angle, higher initial roughness, and significant reduction of roughness AI, compared to Facility. The functional surface height reduced AI, especially in flank and valley of threads. Height of surface roughness of Alvim and Facility implants was similar AI. Implants surface morphology changes and metallic particles on bone beds were observed after implant insertion, mainly into bone types III-IV. Implants inserted into bone types I-II showed less surface damage. Alvim implants released more Ti (37.52 ± 25.03 ppm) than Facility (11.66 ± 28.55 ppm) on bone types III-IV. The implant macrogeometry and bone types affect IT, ISQ, surface damage, and Ti amount released during insertion. Alvim implants were more wear susceptible, releasing higher Ti concentration during insertion into bone types III-IV.

Effect of mandibular residual ridge regularization on peri-implant wound healing when narrow diameter implants are used as overdenture retainers

STATEMENT OF PROBLEM

Alveolar ridge regularization involves the smoothing and minimal reduction of rough alveolar bone ridge to achieve adequate bone thickness around the implant. The effect of this procedure on peri-implant health is unclear.

PURPOSE

The purpose of this clinical study was to evaluate whether bone regularization affects the clinical and biological parameters of peri-implant health when narrow diameter implants are placed as mandibular implant overdenture retainers during initial healing and after occlusal loading.

MATERIAL AND METHODS

The need for mandibular ridge regularization in the anterior mandibular region was analyzed before the placement of 2 implants (2.9×10 mm, Facility; Neodent) in 21 participants provided with mandibular overdentures. Primary stability was measured by the insertion torque and implant stability quotient (ISQ). Clinical and biological evaluations measuring the plaque index, presence of calculus, probing depth, bleeding on probing index, gingival index, secondary stability (ISQ), and interleukine-1β (IL-1β) and tumor necrosis factor-α (TNF-α) concentrations in peri-implant crevicular fluid were measured during osseointegration on days 7, 15, 30, 60, and 90 and after loading on day 180 after implant placement. Multilevel mixed-effects linear regression analysis and the Kaplan-Meier test were used to analyze the data (α=.05).

RESULTS

The ISQ values showed significant differences on days 7 (P<.001) and 15 (P=.002) with higher values and on day 180 (P=.008) with a lower value compared with the baseline value in the ridge regularization group. Additionally, a significant decrease in probing depth was observed on days 60 (P=.008) and 180 (P=.027) compared with that on day 15 after implant placement. In the nonridge regularization group, significant decreases in probing depth were observed on days 30 and 180. Moreover, TNF-α levels in this group were significantly lower on days 30 (P=.001), 60, 90, and 180 (P<.001) when compared with the value on day 7 (P<.001). The ridge regularization group presented with significant differences in TNF-α and IL-1β levels on days 60 (P=.004) and 30 (P=.007), respectively, when compared with the values on day 7. The ISQ and probing depth in the ridge regularization group were associated with changes in TNF-α and IL-1β levels; furthermore, bone type, duration of edentulism, and mandibular bone atrophy were correlated with the clinical outcomes and TNF-α release. The implant survival rate was 67% in the nonridge regularization group and 100% in the ridge regularization group.

CONCLUSIONS

Mandibular ridge regularization appeared to be beneficial for peri-implant healing during the early stages and after 3 months of occlusal loading in patients with an atrophic ridge, prolonged time since edentulism, and poor bone quality.

Clinical Versatility of the Facility-Equator Implant System as Mandibular Overdenture Retainers

The use of mandibular overdentures (MO) for the rehabilitation of totally edentulous individuals with limited bone availability is widespread and has proven clinical success. Narrow diameter implants (NDI) are available on the market as MO retainers to solve problems related to limited bone availability and bone thickness, providing a low-cost, minimally invasive treatment option. This technique evolved over the years, and changes frequently involved the number of implants used as MO retainers, as the adoption of a smaller number of implants can generate biomechanical disadvantages, contributing to the increased stress in peri-implant tissues, which may accelerate marginal bone loss (MBL), in addition to reducing masticatory capacity and satisfaction with rehabilitation. Some studies pointed out that the use of 3 or more implants as MO retainers improves the biomechanics. Thus, the objective of this study was to report 3 different clinical cases where 3 or more NDI were adopted to retain mandibular overdentures in association with diverse loading protocols: (i) 3 implants adopting conventional loading, (ii) 4 implants using progressive loading, and (iii) 4 implants with hybrid loading. The case with 4 implants and progressive loading showed a slight worsening of masticatory function at 1 year, in addition to a more pronounced MBL compared to other cases, but with improvements in satisfaction and oral health-related quality of life. Thus, NDI can be used as MO retainers with predictability and clinical success, using different numbers of implants and loading protocols.

Masticatory function and oral health-related quality of life of patients with atrophic and non-atrophic mandibles using implant-retained mandibular overdentures: 3-year results of a prospective clinical study

BACKGROUND

Long-term changes in masticatory function, oral health-related quality of life (OHRQoL) and prosthetic complications in implant-retained mandibular overdenture (IMO) wearers as a function of bone atrophy require detailed investigations.

OBJECTIVE

Investigating the evolution of masticatory function, OHRQoL and prosthetic occurrences of IMO wearers according to mandibular bone atrophy over 3 years of usage.

METHODS

This study evaluated 26 IMO wearers after 2 and 3 years of IMO loading categorised according to mandibular resorption degree into atrophic mandible (AM) and a non-atrophic mandible (NAM) group. Masticatory function was assessed by the Masticatory Performance (MP) and Swallowing Threshold (ST) tests; OHRQoL and satisfaction via the Dental Impact on Daily Living (DIDL) questionnaire; and the prosthetic maintenance requirements and complications were monitored.

RESULTS

After the second year, the AM Group performed 32% more cycles (P = .047) than the NAM Group during the ST test. The DIDL questionnaire showed no significant difference for all domains, except for a moderate effect size in the General Performance domain after the third year. AM Group had more prosthetic occurrences (n = 109) than NAM Group (n = 60) in the first year, mainly due to Equator attachment dislodgment. During the third year, NAM Group presented a greater number of events (n = 45) than AM Group (n = 21) due to the greater number of O-ring exchanges.

CONCLUSION

Masticatory function and OHRQoL are not related to mandibular bone atrophy until 3 years after IMO rehabilitation. The prosthetic complications profile differs between groups, mainly in the first year.

Immediate vs conventional loading of Facility-Equator system in mandibular overdenture wearers: 1-year RCT with clinical, biological, and functional evaluation

BACKGROUND

The use of immediate loading (IML) is still poorly explored in elderly patients and implant-retained mandibular overdenture (IMO) wearers. For this reason, more comparisons to conventional loading (CL) are required.

PURPOSE

To evaluate the clinical, biological, functional, and oral health-related quality of life (OHRQOL) influence of CL and IML loading on elders wearing IMO retained by the Facility-Equator system up to 1 year after implant installation.

MATERIAL AND METHODS

Twenty edentulous patients received two narrow diameter implants in the mandible; the loading type (CL or IML) was randomized. The clinical parameters were monitored along with prosthetic events, marginal bone loss (MBL) and bone level change (BLC), implant stability quotients (ISQ), masticatory performance outcomes, and Interleukin 1 beta (IL-1β) and tumor necrosis factor alpha (TNF-α) levels in the peri-implant crevicular fluid during the first year of loading. The OHRQoL was assessed via the Oral Health Impact Profile-EDENT questionnaire. Data were analyzed by the Mann-Whitney, χ² , Wilcoxon paired, and McNemar tests.

RESULTS

After 1 year, MBL, BLC and ISQ were statistically identical (P > .05) in the CL and IML groups. The probing depth at 12 months in the CL group (2.19 mm) was higher than in the IML group (1.29 mm; P ≤ .0001). TNF-α was 33.6% higher in the CL group at 6 months (P = .043), while IL-1β was significantly higher in the IML group up to 6 months. The survival rate was 90% in the CL group and 85% in the IML group; 33 prosthetic events occurred in CL group and 23 in IML group.

CONCLUSIONS

After 12 months, both loading protocols are viable and result in similar clinical, biological, functional, and OHRQOL outcomes. However, IML generates better adaptation of the peri-implant tissues, faster improvement in OHRQoL and fewer prosthetic intercurrences than CL.

Mapping of inflammatory biomarkers in the peri-implant crevicular fluid before and after the occlusal loading of narrow diameter implants

OBJECTIVE

To monitor the cytokine release patterns in the peri-implant crevicular fluid (PICF) and to investigate which factors affect the success rate of narrow diameter implants (NDI) during the first year.

MATERIAL AND METHODS

Mandibular implant overdentures (IOD) retained by 2 NDI were installed in 16 clinically atrophic edentulous patients. The following parameters were monitored during the first year: (i) peri-implant health parameters (plaque index (PI), calculus presence (CP), gingival index (GI), probing depth (PD) and bleeding on probing (BoP); (ii) cytokine concentrations in the PICF (TNF-α, IL-1β, IL-6, IL-10); (iii) implant stability quotient (ISQ); (iv) marginal bone level (MBL) and bone level change (BLC); (v) implant success. The insertion torque, bone type, mandibular atrophy, time since edentulism, and smoking habits were also recorded. All data were analyzed using multivariable multilevel mixed-effects regression models.

RESULTS

The variability in the TNF-α release patterns temporarily reduced at weeks (w) 8-12, while the IL-1β concentrations remained low until they peaked at w48 [p < 0.05; + 177.55 pg/μl (+ 96.13 - + 258.97)]. Conversely, IL-10 release decreased significantly at w48 [p < 0.05; - 456.24 pg/μl (- 644.41 - - 268.07)]. The PD and ISQ decreased significantly (p < 0.05) over the follow-up period, while the MBL was stable after w48 with a BLC of 0.12 ± 0.71 mm. The overall success rate was 81.3%, and was influenced by TNF-α, IL-1β, IL-10, PI, GI, PD, smoking, and time since edentulism.

CONCLUSION

Pro- and anti-inflammatory cytokine release was balanced during the first 24 weeks. The GI, smoking, and time since edentulism are the most important factors determining the implant success.

CLINICAL RELEVANCE

The study contributes to the understanding of the osseointegration process in a clinically atrophic population rehabilitated with IOD, and highlights the importance of monitoring clinical peri-implant health-related parameters, smoking habit, and time since edentulism to predict implant success rates.

Influence of Insertion Torque on Clinical and Biological Outcomes before and after Loading of Mandibular Implant-Retained Overdentures in Atrophic Edentulous Mandibles

Aim

To evaluate the influence of primary insertion torque (IT) values of narrow dental implants on the peri-implant health, implant stability, immunoinflammatory responses, bone loss, and success and survival rates.

Methods

Thirty-one edentulous patients received two narrow implants (2.9x10mm, Facility NeoPoros) to retain mandibular overdentures. The implants were categorized in four groups according to their IT: (G1) IT > 10 Ncm; (G2) IT ≥ 10Ncm and ≤ 30 Ncm; (G3) IT >30Ncm and < 45Ncm; (G4) IT ≥ 45Ncm, and all implants were loaded after 3 months of healing. The following clinical outcomes were evaluated 1, 3, 6, and 12 months after implant insertion: (i) peri-implant tissue health (PH), gingival index (GI), plaque index (PI), calculus presence (CP), probing depth (PD), and bleeding on probing (BOP); (ii) implant stability quotient (ISQ) by resonance frequency analysis; and (iii) IL-1β and TNF-α concentration in the peri-implant crevicular fluid. The marginal bone level (MBL) and changes (MBC) were evaluated. The Chi² test, Kruskal-Wallis test, mixed-effects regression analysis, and the Kendall rank correlation coefficient were used for statistical analysis (α = 5%).

Results

G1 presented the highest PD at all evaluated periods. G2 presented higher PI at month 6 and 12. G4 showed increased GI at month 3 and 12 and more CP at month 1 (p=.003). G2 and G4 had higher ISQ values over the study period, while those from G1 and G3 presented lower ISQ values. The IL-1β concentration increased until month 12 and was independent of IT and bone type; G4 had a higher IL-1β concentration in month 3 than the other groups (p=.015). The TNF-α release was negatively correlated with IT, and TNF-α release was highest in G1 at month 12. The MBL immediately after surgery and the MBC at month 12 were similar between the groups, and G4 presented a positive MBC at month 12. The survival and success rates were 75% for G1, 81.3% for G2, 64.3% for G3, and 95% for G4.

Conclusion

The IT did not influence the clinical outcomes and the peri-implant immunoinflammatory responses and was weakly correlated with the narrow dental implants primary stability. The observed success rates suggest that the ideal IT for atrophic fully edentulous patients may deviate from the standardized IT of 32 Ncm.

Retrospective study on the clinical outcomes of small-diameter implants supporting fixed prostheses without bone augmentation in the posterior region after 2 to 12 years

BACKGROUND

Small-diameter implants (SDIs: diameter <3.5 mm) are often chosen as an alternative to bone augmentation in clinical practice, but the scientific evidence regarding SDI application in the posterior area remains deficient.

PURPOSE

To evaluate the clinical and radiographic outcomes of SDIs supporting fixed prostheses without bone augmentation in the posterior region, and to analyze the potential influencing factors related to SDI failures.

MATERIALS AND METHODS

Clinical and radiographic data of 243 SDIs in 156 patients were retrospectively assembled after 2 to 12 (mean 4.75) years of follow-up. Implant and prosthesis failures, mechanical and biological complications, and radiographic marginal bone loss (MBL) were evaluated. The influence of patient/implant characteristics and prosthetic design on SDI failures was investigated.

RESULTS

Five implants in five patients failed, contributing to 10-year cumulative survival rates of 97.9% on an implant-based analysis and 96.8% on a patient-based analysis. Biological complications and mechanical complications were detected in 22 (9.1%) and 31 (12.8%) of implants, respectively. No implant fracture was detected. Peri-implant MBL during 10 years was 0.60 ± 0.90 mm on average. The implant type (bone-level or tissue-level) was the only factor that significantly influenced SDI failures.

CONCLUSION

SDIs supporting fixed prostheses in the posterior region achieved predictable long-term clinical outcomes. However, tissue-level titanium SDIs should be avoided where possible.

In Vitro Effect of Drilling Speed on the Primary Stability of Narrow Diameter Implants with Varying Thread Designs Placed in Different Qualities of Simulated Bone

It is hypothesized that there is no statistically significant impact of drilling speed (DS) on the primary stability (PS) of narrow-diameter implants (NDIs) with varying thread designs placed in dense and soft simulated bone. The aim of this in vitro study was to evaluate the impact of DS on the PS of NDIs with varying thread designs placed in dense and soft simulated bone. Two hundred and forty osteotomies for placement of various implant macro-designs were divided into three groups (80 implants per group): Group A (NobelActive, 3.0/11.5 mm); Group B (Astra OsseoSpeed-EV, 3.0/11 mm); and Group C (Eztetic-Zimmer, 3.1/11.5 mm) implants. These implants were placed in artificial dense and soft simulated bone using DSs of 800 and 2000 revolutions per minute (RPM). Resonance frequency analysis (RFA) and implant stability quotient (ISQ) were assessed. Group comparisons were performed using the one-way analysis of variance with Tukey’s post hoc tests. Level of significance was set at P < 0.05. In groups A and B, there was no difference in the ISQ for NDIs inserted in dense bone at 800 and 2000 RPM. In Group C, ISQ was significantly higher for NDIs placed in dense bone at 800 PRM compared to 2000 RPM (P < 0.05). In Group A, ISQ values were significantly higher for NDIs inserted in soft bone at 2000 RPM as compared to those inserted at 800 RPM (P < 0.05). For NDIs, a lower drilling speed in dense artificial simulated bone and a higher drilling speed in soft artificial simulated bone is associated with high primary stability.