Mini-implants and narrow diameter implants as mandibular overdenture retainers: A systematic review and meta-analysis of clinical and radiographic outcomes.

This study reviews the clinical and radiographic outcomes of Mini-implants (MI) and Narrow Diameter Implants (NDI) as mandibular overdenture (MO) retainers. Six databases were consulted for clinical studies that evaluated implants with diameter ≤3.5 mm. Data on the MI and NDI for survival and success rate and peri-implant bone loss and were collected and submitted to meta-analysis. Thirty-six studies were included, 24 reporting MI performance and 12 describing NDI results. The MI group comprised data from 1 cross-sectional clinical study, 3 retrospective longitudinal (RL) clinical studies, 13 prospective longitudinal (PL) clinical studies and 7 randomised clinical trials (RCT) with follow-up periods ranging from 1 day to 7 years. Eight studies used conventional loading, thirteen used immediate loading, two studies used both loading types, and one study did not report. The NDI group comprised data from 3 RL clinical studies, 6 PL clinical studies and 3 RCT with follow-up ranging from 6 months to 10 years. Ten studies used conventional loading, 1 study used immediate loading, and 1 study did not report. The average survival rates of MI and NDI studies were 98% and 98%, respectively, while the average success rates were 93% and 96%, respectively. The average peri-implant bone loss after 12, 24 and 36 months was 0.89, 1.18 and 1.02 mm for MI and 0.18, 0.12 and -0.32 mm for NDI. Both MI and NDI showed adequate clinical behaviour as overdenture retainers. The NDI showed a better long-term predictability to retain OM with most studies adopting conventional loading.

How does mandibular bone atrophy influence the masticatory function, OHRQoL and satisfaction in overdenture wearers? Clinical results until 1-year post-loading.

This longitudinal clinical study investigated the differences in the masticatory function (MF), satisfaction and oral health-related quality of life (OHRQoL) between atrophic patients (AP) and non-atrophic patients (NAP) before and after rehabilitation with mandibular overdenture (MO). Twenty-six complete denture (CD) wearers were categorised into two groups, according to the mandibular bone atrophy (MBA) degree. MF was evaluated before and after 1, 3, 6 and 12 months of the MO loading via 2 standardised tests: (i) MP, masticatory performance (MP_X50, MPB, ME 5·6, ME 2·8) and (ii) ST, swallowing threshold (time, number of cycles, ST_X50, STB, ME 5·6, ME 2·8). The dental impact on daily living (DIDL) questionnaire measured changes in the satisfaction level and OHRQoL. MP comparisons showed significant difference only for ME 5·6 12 months after MO loading (AP=33·79 ± 23·6; NAP=17·58 ± 20·1). ST presented significant differences before MO loading for: ST_X50 (AP=5·48 ± 0·83; NAP=4·31 ± 1·44), ME 5·6 (AP=53·17 ± 24·71; NAP=29·83 ± 31·45) and ME 2·8 (AP=8·76 ± 6·91; NAP=18·61 ± 10·71). One month after MO loading, NAP performed the ST test 21% faster than AP. After 3 months, significant improvements in STB (AP=4·93 ± 4·82; NAP=2·73 ± 1·27) and ME 2·8 (AP=17·15 ± 10·00; NAP=24·69 ± 7·82) also were observed. DIDL evaluation showed significant differences in the oral comfort domain after 3 months (AP=0·66 ± 0·29; NAP=0·87 ± 0·16) and after 6 months (AP=0·79 ± 0·22; NAP=0·98 ± 0·08), with lower satisfaction levels in the AP. MBA negatively affects the MF mainly the ST. After 6 months, differences between AP and NAP disappeared and ST results were equalised. AP initially has lower satisfaction levels reaching similar levels of satisfaction as NAP after 1 year.

Success rate and complications associated with dental implants in the incisive canal region: a systematic review.

A systematic review was conducted to evaluate the success rate of dental implants placed in the incisive canal region and the complications related to this procedure. An electronic search was performed in the PubMed, Scopus, and Web of Science databases. Articles reporting the incisive canal deflation technique or neurovascular bundle lateralization technique, with or without concomitant dental implant installation and grafting procedures, were evaluated. Ten articles met the inclusion criteria; only one retrospective study and one longitudinal clinical trial were found. A total of 91 implants were installed in this region, and implant success ranged from 84.6% to 100%. With regard to complications, three articles reported temporary sensory loss. Permanent sensory loss in the palatal mucosa region was reported in one study applying neurovascular bundle lateralization. Five studies were assessed in the quality analysis: four were of moderate quality and one was of low quality. Although a high success rate was described in the selected studies, caution is recommended when dental implants are installed in the incisive canal region due to the low level of evidence available. Regarding complications, there are no parameters for predicting the occurrence of sensory disturbances or the extent of damage with the use of incisive canal deflation or neurovascular bundle lateralization.

The split crest technique and dental implants: a systematic review and meta-analysis.

This systematic review aimed to determine: (1) the expected bone volume gain with the split crest technique, and (2) how the use of surgical instruments affects the performance of this technique. An electronic search was performed in the Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, Embase, PubMed/MEDLINE, Scopus, and Web of Science databases. Twenty-seven articles met the selection criteria and were subjected to meta-analysis of bone gain and survival rate; 17 reported the use of conventional surgical instruments and nine the use of surgical ultrasound. A total of 4115 implants were installed in 1732 patients (average patient age 52 years). The overall implant survival rate was 97%. The average bone gain in studies that used conventional surgical instruments was 3.61mm, while this was 3.69mm in those that used ultrasound. Only two studies presented a low risk of bias. The greatest problems identified during the qualitative analysis were related to random selection of the population and the absence of statistical analysis. The split crest technique appears to be a promising and effective technique to gain bone width, regardless of the surgical instruments used. Considering the diversity of the studies and implant types, no definitive recommendations can be made, especially with regard to the best instruments and implant design to be used.

Single and combined effect of high-frequency loading and bisphosphonate treatment on the bone micro-architecture of ovariectomized rats.

UNLABELLED: Mechanical loading at high frequency affects bone. Whether this also applies to osteoporotic bone, combined or not with bisphosphonate therapy, was investigated in this animal study through imaging. An anabolic effect of high-frequency loading on osteoporotic bone, however non-synergistic with bisphosphonates, was found, thereby revealing its potential for treatment of osteoporosis. INTRODUCTION: In an effort to elucidate the effect of high-frequency (HF) loading on bone and to optimize its potential for treatment osteoporosis, this study aimed to investigate the effect of HF loading via whole body vibration (WBV), alone or in association with bisphosphonate treatment (alendronate--ALN), on the micro-architecture of ovariectomy (OVX)-induced compromised bone. METHODS: Eighty-four female Wistar rats were ovariectomized (OVX) or sham-operated (shOVX). OVX animals were treated either with ALN (3 days/week at a dose of 2 mg/kg) or with saline solution. Each group (shOVX, OVX, ALN) was further divided into subgroups relative to the loading status (sham-WBV versus WBV) and the duration of experimental period (4 days versus 14 days). (Sham)WBV loading was applied for 10 min/day using 10 consecutive steps of HF loading (130, 135, 140, 145, 150, 130, 135, 140, 145, 150 Hz). Tibial bone structural responses to WBV and/or ALN treatment were analyzed using ex vivo micro-computed tomography. RESULTS: The animal's hormonal status displayed a major impact on the trabecular and cortical bone structural parameters. Furthermore, mechanical treatment with HF WBV increased the cortical thickness and reduced the medullar area in OVX rats. However, OVX trabecular bone was not affected by HF stimuli. Finally, ALN prevented OVX-associated bone loss, but the association of ALN with WBV did not lead to a synergistic bone response in OVX bone. CONCLUSIONS: HF WBV mechanical stimulation displayed an anabolic effect on osteoporotic cortical bone, confirming its therapeutic properties for enhancing compromised bone. Additionally, its association with bisphosphonates' administration did not produce any additive effect on the bone micro-architecture in the present study.

Micro-CT analysis of the rodent jaw bone micro-architecture: A systematic review.

INTRODUCTION: Knowledge about macro- and micro-structural characteristics may improve in vivo estimation of the quality and quantity of regenerated bone tissue. For this reason, micro-CT imaging has been applied to evaluate alveolar bone remodelling, alterations of periodontal ligament thickness and cortical and trabecular bone changes in rodent jaw bones. In this paper, we provide a systematic review on the available micro-CT literature on jaw bone micro-architecture. METHODOLOGY: A detailed search through the PubMed database was performed. Articles published up to December 2013 and related to maxilla, mandible and condyle with quantitatively analysed bone micro-architectural parameters were considered eligible for inclusion. Two reviewers assessed the search results according to inclusion criteria designed to identify animal studies quantifying the bone micro-architecture of the jaw rodent bones in physiological or drug-induced disease status, or in response to interventions such as mechanical loading, hormonal treatment and other metabolic alterations. Finally, the reporting quality of the included publications was evaluated using the tailored ARRIVE guidelines outlined by Vignoletti and Abrahamsson (2012). RESULTS: Database search, additional manual searching and assessment of the inclusion and exclusion criteria retrieved 127 potentially relevant articles. Eventually, 14 maxilla, 20 mandible and 12 condyle articles with focus on bone healing were retained, and were analysed together with 3 methodological papers. Each study was described systematically in terms of subject, experimental intervention, follow-up period, selected region of interest used in the micro-CT analysis, parameters quantified, micro-CT scanner device and software. The evidence level evaluated by the ARRIVE guidelines showed high mean scores (between 18 and 25; range: 0-25), indicating that most of the selected studies are well-reported. The major obstacles identified were related to sample size calculation, absence of adverse event descriptions, randomization or blinding procedures. CONCLUSIONS: The evaluated studies are highly heterogeneous in terms of research topic and the different regions of interest. These results illustrate the need for a standardized methodology in micro-CT analysis. While the analysed studies do well according to the ARRIVE guidelines, the micro-CT procedure is often insufficiently described. Therefore we recommend to extend the ARRIVE guidelines for micro-CT studies.

A double-blind randomised clinical trial of two techniques for gingival displacement.

Knowledge about security and the potential damage originated by the gingival displacement techniques has not been described through randomised clinical studies. This crossover, double-blind, randomised clinical trial evaluated clinical and immunological factors related to conventional and cordless gingival displacement (GD) techniques, and patients' perceptions in 12 subjects with the employment of 2 GD techniques: conventional (gingival cord + 25% AlCl3 astringent gel) and cordless (15% AlCl3 astringent-based paste). In each subject, two anterior teeth were treated and a 10-day wash-out period separated the two treatments. Periodontal indices were evaluated before (baseline) and 1 and 10 days after GD. Interleukin 1ß, interleukin 6 and tumour necrosis factor α concentrations in gingival crevicular fluid were measured before and 1 day after GD. Subjective parameters (pain, unpleasant taste and stress) were also evaluated. Data were analysed by one-way repeated-measures analysis of variance and Tukey's test (immunological factors), the Friedman test (periodontal parameters) and Fisher's exact or chi-squared test (subjective parameters), with a significance level of 95%. Gingival bleeding index, probing depth and plaque index values did not differ significantly between groups at any timepoint. Neither technique resulted in worse periodontal indices. Both techniques yielded similar results for pain and unpleasant taste, but conventional GD was significantly more stressful than cordless GD for volunteers. Both treatments significantly increased mean concentrations of the three cytokines, with the conventional technique producing the highest cytokine levels. Cordless GD is less stressful for patients and results in lower post-treatment levels of inflammatory cytokines compared with conventional GD.

Masticatory features, EMG activity and muscle effort of subjects with different facial patterns.

It has been suggested that craniofacial morphology plays an important role in masticatory function, however, there are controversies and unsolved questions that still require elucidation. The aims of this study were to evaluate masticatory performance, mandibular movement, electromyographic (EMG) activity and muscle effort of masseter and anterior temporal muscles during mastication. Seventy-eight dentate subjects were selected and divided into three groups according to vertical facial pattern: brachyfacial, mesofacial and dolichofacial. Silicon-based material was used for chewing tests. Masticatory performance was determined by a 10-sieve method, and masticatory movements during mastication were assessed using a 3D mandibular tracking device. Electromyographic activities of masseter and anterior temporal muscles were evaluated during mastication, and muscle effort was calculated by the percentage of activity required for mastication based on maximum muscle effort. Data were analysed using anova and anova on-ranks tests. Dolichofacial subjects presented significantly poorer masticatory performance (6·64±2·04; 4·33±0·70 and 3·67±0·63), slower rate of chewing (1·34±0·27, 1·18±0·22 and 1·21±0·20 cycles per second) and larger posterior displacement during mastication (6·22±2·18; 5·18±1·87 and 5·13±1·89) than meso- and brachyfacial individuals, respectively. No statistical difference was detected among groups for the other masticatory movement parameters. There was no difference in absolute EMG amplitudes of masseter and anterior temporal muscles during mastication among groups, but the relative effort of both muscles was higher in dolichofacial, followed by meso- and brachyfacial subjects (masseter: 39·34± 2·25; 36·87±4·05 and 33·33±4·15; anterior temporal: 38·12±1·61; 38·20±8·01 and 35·75±2·48). It was concluded that the vertical facial pattern influences masticatory performance, mandibular movement during mastication and the effort masticatory muscles required for chewing.