Relationships between implant stability, image-based measures and nitric oxide levels

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.

Nitric oxide and arginase levels in peri-implant tissues after delayed loading

OBJECTIVE

Nitric oxide (NO) is synthesized from the conversion of L-arginine to L-citrulline by NO synthase (NOS). Arginase can compete with NOS for the common substrate L-arginine, and thus inhibit NO production. NO levels and arginase ezyme might affect the bone remodeling cycle around implants. The aim of this studywas to investigate NO and arginase levels in gingival crevicular fluid (GCF), peri-implant sulcular fluid (PISF), and saliva.

MATERIALS AND METHODS

Twenty patients with one or more implants (Straumann^®; Institute Straumann AG, Basel, Switzerland) restored with fixed crown prostheses were included in the study. Plaque index (PI), gingival index (GI), probing depth (PD), and bleeding on probing (BOP) were recorded from six sites of each tooth and implant at baseline and at months 1, 3, and 6 after loading. The saliva, GCF, and PISF were collected at baseline and at months 1, 3, and 6 after loading. NO level and arginase enzyme were evaluated in GCF, PISF, and saliva.

RESULTS

Arginase and NO levels in saliva did not change significantly from baseline to months 1, 3, and 6. However, both PISF NO and arginase levels showed an increased pattern from baseline to month 6. NO levels were significantly higher at months 3 and 6, compared to baseline, while PISF arginase levels increased significantly from baseline to months 3 and 6.

CONCLUSION

NO and arginase enzyme measurements in saliva, GCF, and PISF may be beneficial in the determination of current peri-implant tissues. In particular, PISF might provide more information than saliva.

Comparison between inflammation-related markers in peri-implant crevicular fluid and clinical parameters during osseointegration in edentulous jaws

OBJECTIVES

The aim of this study is to improve the understanding of interleukin mechanisms during osseointegration to enhance the monitoring of implant failure and success. Clinical parameters, implant stability, and cytokine levels in peri-implant crevicular fluid (PICF) during early bone healing after implant placement were investigated.

MATERIAL AND METHODS

Sixty narrow implants were placed in mandible anterior region of 30 edentulous patients (67.23 ± 7.66 years). Bone type, insertion torque, and primary stability were registered during surgery. Clinical measurements of peri-implant health and the secondary implant stability quotient (ISQ) were recorded. Samples from the PICF were collected 1, 2, 4, 8, and 12 weeks after surgery and analyzed for IL-1β, IL-6, IL-10, and TNF-α levels using ELISAs.

RESULTS

The gingival index increased significantly during the first week (p = 0.05), while the plaque index increased significantly between 4 to 8 and 8 to 12 weeks (p < 0.05). The probing depth and the ISQ also reduced significantly (p < 0.05) over time. The TNF-α release increased significantly after the 2nd week for non-atrophic patients and 4th week for atrophic patients (p < 0.05). The IL-1β concentrations showed a short-lived peak after 1st week (p = 0.003), specially in atrophic patients and sites with bone type I (p = 0.034; p = 0.007). The IL-6 concentrations peaked during the 1st and 2nd weeks (p < 0.05; p = 0.005) in atrophic patients and in bone type II (p = 0.023; p = 0.003). The IL-10 concentrations increased gradually over time, showing the highest concentrations at the 12th week (p < 0.005). A total of 12 implants failed at different periods.

CONCLUSION

While the clinical measurements presented differences between the evaluation periods, these were not indicative of early dental implant failure or peri-implant diseases. Smoking, bone atrophy, and bone type can greatly influence the cytokines concentrations during the healing time.

Nitric oxide in human gingival crevicular fluid after orthodontic force application

Nitric oxide (NO) is involved in bone remodelling and has been shown to play a role in regulating the rate of orthodontic tooth movement (OTM) in rat models. In humans, however, the role of NO in OTM remains less clear. In this study, NO concentration in gingival crevicular fluid (GCF) was measured in patients undergoing orthodontic treatment. Thirteen male participants (ages 11-18 years) planned for non-extraction fixed orthodontic therapy were recruited. Samples of GCF were collected from each maxillary central incisor and first and second molar immediately before (T0), 1h after (T1), and 3-4 days after (T2) application of light orthodontic forces. The maxillary second molars were not included in the appliance and served as controls. Measureable NO levels were consistently obtained from all sampled sites. Total NO levels showed significantly higher NO levels (p<0.05) at T1 at the buccal surfaces of the central incisors when compared to the first and second molars. The results indicate a possible role for NO in OTM at the pressure sites of incisors at early time points. Further studies are required to determine whether NO levels in the periodontal ligament tissues of human teeth during OTM are affected by a force gradient and the magnitude of the applied force.

The correlation between crestal bone resorption and implant stability during healing period using resonance frequency analysis

PURPOSE

To detect the correlation between crestal bone resorption and implant stability during healing period using resonance frequency analysis (RFA).

MATERIALS AND METHODS

Twenty-two International Team for Implantology Straumann implants were placed in the posterior maxilla or mandible in 9 patients. RFA reading was taken immediately after implant placement. Periapical radiographs were taken, and the distance from the shoulder of the healing cap to the first bone-implant contact was measured, and the average mesial and distal distances were taken. Patients were followed up at 6 and 12 weeks for data collection.

RESULTS

At 6 weeks, the correlation between crestal bone resorption and implant stability was significant (Spearman correlation test, P < 0.05) and negative correlation coefficient (r) was -0.522. At 12 weeks, the correlation between crestal bone resorption and implant stability was not significant (Spearman correlation test, P > 0.05) and negative correlation coefficient (r) was -0.119.

CONCLUSIONS

There was a significant negative correlation between the crestal bone resorption and implant stability at 6 weeks, whereas the negative correlations between the crestal bone resorption and implant stability at 12 weeks were nonsignificant.

Interventions for replacing missing teeth: different times for loading dental implants

BACKGROUND

To minimise the risk of implant failures after their placement, dental implants are kept load-free for 3 to 8 months to establish osseointegration (conventional loading). It would be beneficial if the healing period could be shortened without jeopardising implant success. Nowadays implants are loaded early and even immediately and it would be useful to know whether there is a difference in success rates between immediately and early loaded implants compared with conventionally loaded implants.

OBJECTIVES

To evaluate the effects of (1) immediate (within 1 week), early (between 1 week and 2 months), and conventional (after 2 months) loading of osseointegrated implants; (2) immediate occlusal versus non-occlusal loading and early occlusal versus non-occlusal loading; (3) direct loading versus progressive loading immediately, early and conventionally.

SEARCH METHODS

The following electronic databases were searched: the Cochrane Oral Health Group's Trials Register (to 8 June 2012), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2012, Issue 4), MEDLINE via OVID (1946 to 8 June 2012) and EMBASE via OVID (1980 to 8 June 2012). Authors of identified trials were contacted to find unpublished randomised controlled trials (RCTs). There were no restrictions regarding language or date of publication.

SELECTION CRITERIA

All RCTs of root-form osseointegrated dental implants, having a follow-up of 4 months to 1 year, comparing the same implant type immediately, early or conventionally loaded, occlusally or non-occlusally loaded, or progressively loaded or not. Outcome measures were: prosthesis and implant failures and radiographic marginal bone level changes.

DATA COLLECTION AND ANALYSIS

Data were independently extracted, in duplicate, by at least two review authors. Trial authors were contacted for missing information. Risk of bias was assessed for each trial by at least two review authors, and data were extracted independently, and in duplicate. Results were combined using fixed-effect models with mean differences (MD) for continuous outcomes and risk ratios (RR) for dichotomous outcomes with 95% confidence intervals (CI). A summary of findings table of the main findings was constructed.

MAIN RESULTS

Forty-five RCTs were identified and, from these, 26 trials including a total of 1217 participants and 2120 implants were included. Three trials were at low risk of bias, 12 were at high risk of bias and for the remaining 11 the risk of bias was unclear. In nine of the included studies there were no prosthetic failures within the first year, with no implant failures in 7 studies and the mean rate of implant failure in all 26 trials was a low 2.5%. From 15 RCTs comparing immediate with convential loading there was no evidence of a difference in either prosthesis failure (RR 1.87; 95% CI 0.70 to 5.01; 8 trials) or implant failure (RR 1.65; 95% CI 0.68 to 3.98; 10 trials) in the first year, but there is some evidence of a small reduction in bone loss favouring immediate loading (MD -0.10 mm; 95% CI -0.20 to -0.01; P = 0.03; 9 trials), with some heterogeneity (Tau² = 0.01; Chi² = 14.37, df = 8 (P = 0.07); I² = 44%). However, this very small difference may not be clinically important. From three RCTs which compared early loading with conventional loading, there is insufficient evidence to determine whether or not there is a clinically important difference in prosthesis failure, implant failure or bone loss. Six RCTs compared immediate and early loading and found insufficient evidence to determine whether or not there is a clinically important difference in prosthesis failure, implant failure or bone loss. From the two trials which compared occlusal loading with non-occlusal loading there is insufficient evidence to determine whether there is a clinically important difference in the outcomes of prosthesis failure, implant failure or bone loss. We did not identify any trials which evaluated progressive loading of implants.

AUTHORS' CONCLUSIONS

Overall there was no convincing evidence of a clinically important difference in prosthesis failure, implant failure, or bone loss associated with different loading times of implants. More well-designed RCTs are needed and should be reported according to the CONSORT guidelines (www.consort-statement.org/).

Would Nitric Oxide be an Effective Marker for Earlier Stages of Peri-Implant Disease? An Analysis in Human Peri-Implant Sulcular Fluid

Nitric oxide has an important effect on host immune response. However, little has been studied in relation to its potential as a possible diagnostic tool in peri-implant disease. The present study analyzed nitrite levels in the peri-implant sulcular fluid (PISF) of implants with mucositis and the correlation of these nitrite levels with clinical parameters using a simplified fluid collection methodology. Twenty-five partially edentulous patients showing peri-implant mucositis were evaluated, and the peri-implant status was determined based on current clinical parameters: probing depth (PD) and bleeding on probing (BOP). The sulcular fluid (SF) around teeth (control) and implants were collected, and the nitrite levels were evaluated using the Griess method. The mean probing depth (mm) was significantly higher (P &lt; .0001) in implants (2.852 ± 0.6484) than in control teeth (1.585 ± 0.3636). The mean total nitrite level (μM) was statistically higher (P = .0069) in implants with mucositis (14.34 ± 11.83) than in control teeth (9.316 ± 5.534). No correlation was observed between the total nitrite levels and the PD mean in the control group (P = .2558, r = −0.2361) or in the implant group (P = .1160, r = −0.3224), as well as the number of faces showing bleeding on probing (P = .8747, r = 0.0332). These results demonstrated that the nitrite levels were higher in inflamed areas. According to the methodology applied and results obtained, the higher nitrite levels in inflamed areas suggest that, in the future, nitrite could be used as a marker of peri-implant mucositis associated with clinical data to monitor the cure or evolution of the disease.

Influence of bony defects on implant stability

INTRODUCTION

The purpose of this study was to analyze the evolution of implant mechanical stability in different types/sizes of bony defects using both Periotest and Osstell devices as "objective tools."

MATERIALS AND METHODS

Thirty-two implants were randomly allocated to one of the four types of bone defects: marginal bone loss, peri-apical bone defect, constant width dehiscence and constant length dehiscences. Periotest/Osstell measurements were completed before and during staged bone removal (to enlarge defect size).

RESULTS

Significant differences (P<0.05) with initial values were found after a 2 mm marginal bone removal (Osstell/Periotest); for a peri-apical bone lesion, after removal of 5 mm (Osstell) or 8 mm (Periotest); for a 6-mm-long dehiscence, after removal up to 180 degrees of the implant perimeter (Osstell/Periotest); for a 3-mm-wide dehiscence, after removal of 10 mm (Osstell) or 6 mm (Periotest).

CONCLUSION

Periotest and Osstell are in general not very sensitive in the identification of peri-implant bone destruction, except for marginal bone loss.

Initial stability of two dental implant systems: influence of buccolingual width and probe orientation on resonance frequency measurements

BACKGROUND

Although many factors seem to have an impact on the resonance frequency (RF) values of implants, there is a lack of evidence about some other parameters, which may have an influence on implant stability.

PURPOSE

The aims of the study were to determine whether initial stability of a dental implant differs when the buccolingual width of the bone changes, to determine whether different orientations affect the RF measurements in the RF device, and to investigate two dental implants with different morphologies with regard to their initial stability.

MATERIALS AND METHODS

Two implant systems (Tidal Spiral Dental Implant Systems, Huntsville, AL, USA, and MIS Seven, MIS Implants Technologies Ltd., Shlomi, Israel) with diameters of 3.75 mm and 4.2 mm and with a length of 13 mm were used. Following the insertion of implants, buccolingual thinning of the models was performed in 2-mm increments ranging between 0 and 8 mm.

RESULTS

A statistically significant decrease for implant stability quotient (ISQ) values was noticed for both diameters and both systems for all dimensional time points of the blocks (p < .05). The second system (more number of threads) resulted with higher ISQ values for both diameters than the first system (lower number of threads) (p < .001). The orientation of the probe influenced the measurements, where a standard orientation is advisable for the magnetic RF device.

CONCLUSION

Different implant surface geometries seem to behave in different patterns in terms of initial stability. Dimensional changes in buccolingual direction seem to have an impact on the initial stability, where wider implants also presented higher ISQ values than narrow ones.

Interventions for replacing missing teeth: different times for loading dental implants

BACKGROUND

To minimize the risk of implant failure, osseointegrated dental implants are conventionally kept load-free during the healing period. During healing removable prostheses are used, however many patients find these temporary prostheses rather uncomfortable and it would be beneficial if the healing period could be shortened without jeopardizing implant success. Nowadays immediately and early loaded implants are commonly used in mandibles (lower jaws) of good bone quality. It would be useful to know whether there is a difference in success rates between immediately or early loaded implants compared with conventionally loaded implants.

OBJECTIVES

To evaluate the efficacy of (1) immediate (within 1 week), early (between 1 week and 2 months), and conventional (after 2 months) loading of osseointegrated implants, and of (2) immediate occlusal versus non-occlusal loading during the bone healing phase.

SEARCH STRATEGY

The Cochrane Oral Health Group's Trials Register, CENTRAL, MEDLINE and EMBASE were searched. Handsearching included several dental journals. Authors of all identified trials, an Internet discussion group and 55 dental implant manufacturers were contacted to find unpublished randomised controlled trials (RCTs). The last electronic search was conducted on 4 June 2008.

SELECTION CRITERIA

All RCTs of root-form osseointegrated dental implants, having a follow up of 4 months to 1 year, comparing the same implant type immediately, early and conventionally loaded or occlusally and non-occlusally loaded. Outcome measures were: prosthesis and implant failures and radiographic marginal bone level changes.

DATA COLLECTION AND ANALYSIS

Data were independently extracted, in duplicate, by two review authors. Authors were contacted for details of randomisation and withdrawals and a quality assessment was carried out. The Cochrane Collaboration's statistical guidelines were followed.

MAIN RESULTS

Thirty RCTs were identified and 22 trials including 976 participants in total were included. Twelve trials compared immediate versus conventional loading, three early versus conventional loading, six immediate versus early loading, and one occlusally versus non-occlusally loaded implants. On a patient, rather than per implant basis, there were no statistically significant differences for any of the meta-analyses.

AUTHORS' CONCLUSIONS

It is possible to successfully load dental implants immediately or early after their placement in selected patients, though not all clinicians may achieve optimal results. It is unclear whether it is beneficial to avoid occlusal contacts during the osseointegration phase. Trends suggest that immediately loaded implants fail more often than those conventionally loaded, but less commonly than those loaded early. If a clinician wishes to load the implants early, it might be wiser to load them immediately (within 1 week) rather than waiting for 1 or 2 months. A high degree of primary implant stability (high value of insertion torque) seems to be one of the prerequisites for a successful immediate/early loading procedure. More well designed RCTs are needed and should be reported according to the CONSORT guidelines (www.consort-statement.org/).