Immediate versus conventional loading of palatal implants in humans: a first report of a multicenter RCT

Bone remodelling patterns around orthodontic mini-implants migrating in bone: an experimental study in rat vertebrae

Background

Orthodontic implant migration has been clinically observed in presence of continuous loading forces. Recent studies indicate that osteocytes play a crucial role in this phenomenon.

Objectives

Aim of this study was to investigate local osteocytic gene expression, protein expression, and bone micro-structure in peri-implant regions of pressure and tension.

Material and methods

The present work reports a complementary analysis to a previous micro-computed tomography study. Two customized mini-implants were placed in one caudal rat vertebra and connected by a nickel–titanium contraction spring generating different forces (i.e. 0, 0.5, 1.0, and 1.5 N). Either at 2 or 8 weeks, the vertebrae were harvested and utilized for 1. osteocytic gene expression using laser capture micro-dissection on frozen sections coupled with qPCR, 2. haematoxylin–eosin staining for qualitative and quantitative analyses, 3. immunofluorescence staining and analysis, and 4. bone-to-implant contact on undecalcified samples.

Results

At the two time points for all the performed analyses no significant differences were observed with respect to the applied force magnitudes and cell harvesting localization. However, descriptive histological analysis revealed remarkable bone remodelling at 2 weeks of loading. At 8 weeks the implants were osseointegrated and, especially in 1.0 and 1.5 N groups, newly formed bone presented a characteristic load bearing architecture with trabecula oriented in the direction of the loading.

Conclusions

The present study confirmed that stress-induced bone remodelling is the biological mechanism of orthodontic implant migration. Bone apposition was found at ‘tension’ and ‘pressure’ sites thus limiting implant migration over time.

Influence of subcrestal implant placement compared with equicrestal position on the peri-implant hard and soft tissues around platform-switched implants: a systematic review and meta-analysis

AIM

The aim of this article is to systematically review the effect of subcrestal implant placement compared with equicrestal position on hard and soft tissues around dental implants with platform switch.

MATERIAL AND METHODS

A manual and electronic search (National Library of Medicine and Cochrane Central Register of Controlled Trials) was performed for animal and human studies published up to December 2016. Primary outcome variable was marginal bone level (MBL) and secondary outcomes were crestal bone level (CBL), soft tissue dimensions (barrier epithelium, connective tissue, and peri-implant mucosa), and changes in the position of soft tissue margin. For primary and secondary outcomes, data reporting mean values and standard deviations of each study were extracted and weighted mean differences (WMDs) and 95% confidence intervals (CIs) were calculated.

RESULTS

A total of 14 publications were included (7 human studies and 7 animal investigations). The results from the meta-analyses have shown that subcrestal implants, when compared with implants placed in an equicrestal position, exhibited less MBL changes (human studies: WMD = - 0.18 mm; 95% CI = - 1.31 to 0.95; P = 0.75; animal studies: WMD = - 0.45 mm; 95% CI = - 0.66 to - 0.24; P < 0.001). Furthermore, the CBL was located at a more coronal position in subcrestal implants with respect to the implant shoulder (WMD = - 1.09 mm; 95% CI = - 1.43 to - 0.75; P < 0.001). The dimensions of the peri-implant mucosa seem to be affected by the positioning of the microgap and were greater at implants placed in a subcrestal position than those inserted equicrestally (WMD = 0.60 mm; 95% CI = 0.26 to 0.95; P < 0.001). While the length of the barrier epithelium was significantly greater in implants placed in a subcrestal position (WMD = 0.39 mm; 95% CI = 0.19 to 0.58; P < 0.001), no statistical significant differences were observed between equicrestal and subcrestal implant positioning for the connective tissue length (WMD = 0.17 mm; 95% CI = - 0.03 to 0.36; P = 0.10).

CONCLUSION

This systematic review suggests that PS implants placed in a subcrestal position have less MBL changes when compared with implants placed equicrestally. Furthermore, the location of the microgap seems to have an influence on the dimensions of peri-implant soft tissues. Clinical relevance When compared with PS placed in an equicrestal position, subcrestal implant positioning demonstrated less peri-implant bone remodeling.

Implants for orthodontic anchorage: success rates and reasons of failures

INTRODUCTION

The aims of this study were to analyze the success rate of mini-implants and miniscrews and to report the reasons behind them.

MATERIALS AND METHODS

An electronic literature search from PubMed databases and a hand search in implant- and orthodontic-related journals were performed until December 31, 2011. Human clinical studies in English that reported temporary anchorage devices used for orthodontic purpose with at least 6 months follow-up were included. In addition, the minimal number of implants had to be at least 10. Implants placed in maxilla, mandible, and hard palate were included.

RESULTS

The initial search resulted in 847 articles, of which 46 were further evaluated. Finally, 29 studies were qualified and classified into 2 groups: implants placed in maxilla and mandible (group 1) and implants placed in hard palate (group 2). A meta-analysis performed for groups 1 and 2 showed 87.8% and 93.8% survival rate, respectively. In addition, the most common cause for implants failure was surgery-related factors.

CONCLUSION

Mini-implant survival rate is location dependent, with those placed in the palate showing higher success rates. In addition, failures most commonly occur because of surgery-related factors.

Clinical efficacy of immediate implant loading protocols compared to conventional loading depending on the type of the restoration: a systematic review

BACKGROUND AND OBJECTIVES

Immediate loading has become a predictable option to restore all clinical situations. The aim of this systematic review was to assess whether immediate loading protocols achieve comparable clinical outcomes when compared to conventional loading protocols depending on the type of prosthetic restoration.

METHODS

A protocol was developed aimed to answer the following focused question: "What are the effects of immediate implant loading protocols compared to conventional implant loading, in terms of implant failure, marginal bone levels, and biological and mechanical complications based on the type of restoration?" The next subanalysis were performed as follows: the extent, type, and material of the restoration and the type of occlusal contact in function. This systematic review only included randomized controlled trials (RCTs) with a follow-up of at least 6 months after implant loading.

RESULTS

Thirty-seven final papers were included. The results from the meta-analyses have shown that the immediately loading implants demonstrated a statistically significant higher risk of implant failure [RR = 1.92; 95% CI (1.04; 3.54); P = 0.036], a statistically significant lower bone loss [WMD = 0.046; 95% CI (0.043; 0.049); P = 0.000] and a smaller increase in ISQ values [WMD = -1.096; 95% CI (-1.615; -0.577); P < 0.001, although both groups attained high survival rates (98.2% in the test and 99.6% in the control). Single teeth implants were greater risk of failure, when compared to immediately loaded full arch restorations (RR = 2 vs. 0.9), so as the occlusal pattern when compared to non-occlusal (RR = 1.9 vs. 1.4).

CONCLUSIONS

Immediate loading may impose a greater risk for implant failure when compared to conventional loading, although the survival rates were high for both groups.

Reinforcement of anchorage during orthodontic brace treatment with implants or other surgical methods

BACKGROUND

The term anchorage in orthodontic treatment refers to methods of controlling unwanted tooth movement. This is provided either by anchor sites within the mouth, such as the teeth and the palate, or from outside the mouth (headgear). Recently, new methods of providing anchorage have been developed using orthodontic implants which are surgically inserted into the bone in the mouth. This is termed surgical anchorage. This is an update of a Cochrane review first published in 2007.

OBJECTIVES

To assess the effects of surgical anchorage techniques compared to conventional anchorage in the prevention of unwanted tooth movement in patients undergoing orthodontic treatment by evaluating the mesiodistal movement of upper first molar teeth. A secondary objective was to compare the effects of one type of surgical anchorage with another.

SEARCH METHODS

We searched the Cochrane Oral Health Group's Trials Register (to 28 October 2013), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 9), MEDLINE via OVID (1946 to 28 October 2013) and EMBASE via OVID (1980 to 28 October 2013). We handsearched key international orthodontic and dental journals, and searched the trial database ClinicalTrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform for ongoing and unpublished studies.

SELECTION CRITERIA

Randomised controlled trials comparing surgical anchorage with conventional anchorage in orthodontic patients. Trials comparing two types of surgical anchorage were also included.

DATA COLLECTION AND ANALYSIS

At least two review authors independently and in duplicate extracted data and carried out risk of bias assessments. We contacted study authors to clarify aspects of study design and conduct, and to obtain unreported data.

MAIN RESULTS

Fourteen new studies were added in this update resulting in a total of 15 studies reporting data from 561 randomised patients. The studies were conducted in Europe, India, China, South Korea and the USA. The age range of patients was commonly restricted to adolescents or young adults, however the participants of two studies were from a much wider age range (12 to 54 years). The distribution of males and females was similar in eight of the studies, with a predominance of female patients in seven studies.Eight studies were assessed to be at high overall risk of bias; six studies at unclear risk of bias; one study at low risk of bias.Ten studies with 407 randomised and 390 analysed patients compared surgical anchorage with conventional anchorage for the primary outcome of mesiodistal movement of upper first molars. We carried out a random-effects model meta-analysis for the seven studies that fully reported this outcome. There was strong evidence of an effect of surgical anchorage on this outcome. Compared with conventional anchorage, surgical anchorage was more effective in the reinforcement of anchorage by 1.68 mm (95% confidence interval (CI) -2.27 mm to -1.09 mm; seven studies, 308 participants analysed) with moderate quality of evidence (one study at high overall risk of bias, five studies at unclear risk of bias, one study at low risk of bias). This result should be interpreted with some caution, however, as there was a substantial degree of heterogeneity for this comparison. There was no evidence of a difference in overall duration of treatment between surgical and conventional anchorage (-0.15 years; 95% CI -0.37 years to 0.07 years; three studies, 111 analysed patients) with low quality of evidence (one study at high overall risk of bias and two studies at unclear risk of bias). Information on patient-reported outcomes such as pain and acceptability was limited and inconclusive.When direct comparisons were made between two types of surgical anchorage, there was a lack of evidence to suggest that any one technique was better than another.No included studies reported adverse effects.

AUTHORS' CONCLUSIONS

There is moderate quality evidence that reinforcement of anchorage is more effective with surgical anchorage than conventional anchorage, and that results from mini-screw implants are particularly promising. While surgical anchorage is not associated with the inherent risks and compliance issues related to extraoral headgear, none of the included studies reported on harms of surgical or conventional anchorage.

Changes in mastication after an immediate loading implantation with complete fixed rehabilitation

OBJECTIVE

This study aimed to measure modifications of mastication after immediate loading full-arch prosthesis (ILFAP) rehabilitation.

MATERIALS AND METHOD

Fourteen patients were observed before and 6 months after ILFAP rehabilitation when masticating two natural, standardized foods (peanut and carrot) and three model foods with increasing hardness. The granulometry of the expectorated boluses from carrot and peanuts was characterized by median particle size (D50), determined at the natural point of swallowing. Chewing time (CT), number of chewing cycles (CC), and chewing frequency (CF) were video recorded. A self-assessment questionnaire for oral health-related quality of life [Geriatric Oral Health Assessment Index (GOHAI)] was also used.

RESULTS

After ILFAP rehabilitation, the mean D50 values for carrot and peanuts were smaller [Repeated Model Procedures (RMP), F = 41, p < 0.001]. Mean CT and CC values recorded with the three model foods decreased, while CF increased regardless of the model food hardness (RMP, F = 14, F = 10, and F = 11, respectively, p < 0.001). The GOHAI score increased from 43 ± 9 to 56 ± 3 (t test, p < 0.001).

CONCLUSION

ILFAP rehabilitation improves the ability to reduce the bolus particle size and the ability to discriminate between different food hardnesses in the 6 months post-surgery period.

CLINICAL RELEVANCE

This study encourages the clinical development of immediate loading implantation with a fixed full-arch prosthesis protocol.