Conchita Martin

Surgical protocols for ridge preservation after tooth extraction. A systematic review

OBJECTIVE This systematic review aims to evaluate the scientific evidence on the efficacy in the surgical protocols designed for preserving the alveolar ridge after tooth extraction and to evaluate how these techniques affect the placement of dental implants and the final implant supported restoration. MATERIAL AND METHODS A thorough search in MEDLINE-PubMed, Embase and the Cochrane Central Register of controlled trials (CENTRAL) was conducted up to February 2011. Randomized clinical trials and prospective cohort studies with a follow-up of at least 3 months reporting changes on both the hard and soft tissues (height and/or width) of the alveolar process (mm or %) after tooth extraction were considered for inclusion. RESULTS The screening of titles and abstracts resulted in 14 publications meeting the eligibility criteria. Data from nine of these 14 studies could be grouped in the meta-analyses. Results from the meta-analyses showed a statistically significant greater ridge reduction in bone height for control groups as compared to test groups (weighted mean differences, WMD = -1.47 mm; 95% CI [-1.982, -0.953]; P < 0.001; heterogeneity: I(2) = 13.1%; χ(2) P-value = 0.314) and a significant greater reduction in bone width for control groups compared to the test groups (WMD = -1.830 mm; 95% CI [-2.947, -0.732]; P = 0.001; heterogeneity: I(2) = 0%; χ(2) P-value = 0.837). Subgroup analysis was based on the surgical protocol used for the socket preservation (flapless/flapped, barrier membrane/no membrane, primary intention healing/no primary healing) and on the measurement method utilized to evaluate morphological changes. Meta-regression analyses demonstrated a statistically significant difference favoring the flapped subgroup in terms of bone width (meta-regression; slope = 2.26; 95% IC [1.01; 3.51]; P = 0.003). CONCLUSIONS The potential benefit of socket preservation therapies was demonstrated resulting in significantly less vertical and horizontal contraction of the alveolar bone crest. The scientific evidence does not provide clear guidelines in regards to the type of biomaterial, or surgical procedure, although a significant positive effect of the flapped surgery was observed. There are no data available to draw conclusions on the consequences of such benefits on the long-term outcomes of implant therapy.

Clinical evaluation of a new collagen matrix (Mucograft® prototype) to enhance the width of keratinized tissue in patients with fixed prosthetic restorations: a randomized prospective clinical trial

AIM The aim of this study was to test a new collagen matrix (CM) aimed to increase keratinized gingiva/mucosa when compared with the free connective tissue graft (CTG). MATERIAL AND METHODS This randomized longitudinal parallel controlled clinical trial studied 20 patients with at least one location with minimal keratinized tissue (<or=1 mm). MAIN OUTCOME MEASURE The 6-month width of keratinized tissue. As secondary outcomes, the aesthetic outlook, the maintenance of periodontal health and the patient morbidity were assessed pre-operatively at 1, 3 and 6 months. RESULTS At 6 months, the CTG attained a mean width of keratinized tissue of 2.6 (0.9) mm, while the CM was 2.5 (0.9) mm, these differences being insignificant. In both groups, there was a marked contraction (60% and 67%, respectively) although the periodontal parameters were not affected. The CM group had a significantly lower patient morbidity (pain and medication intake) as well as reduced surgery time. CONCLUSIONS These results prove that this new CM was as effective and predictable as the CTG for attaining a band of keratinized tissue, but its use was associated with a significantly lower patient morbidity.

Diagnosis of implant stability and its impact on implant survival: a prospective case series study

OBJECTIVES To assess the predictability of implant stability assessment either clinically or by resonance frequency analysis (RFA). MATERIAL AND METHODS This prospective case series study evaluated 4114 consecutive SLA Straumann implants in two private clinics. Primary stability was classified in four categories, depending on the degree of implant rotation when tightening the healing cap: A (no rotation at all), B (light rotation with a feeling of resistance), C (rotation without resistance) and D (rotation and lateral oscillation). In one clinic (n=542 implants), RFA method was also used the day of the surgery (Osstell 1) and at restoration placement (Osstell 2). Survival rates were stratified according to the clinical classification categories using life table analysis. The association between Osstell 1 and 2 and the clinical classification was tested with ANOVA. RESULTS 3899 implants were classified as stable (A) and 213 as unstable (B-D). Their survival rates were 99.1% and 97.2%, respectively. The unstable implants were further classified in B (158), C (51) and D (4), with survivals of 98.1%, 94.1% and 100%, respectively, being these differences statistically significant (P<0.009). Using Osstell, implants were stratified in two groups according to a predefined threshold of implant stability quotient (>or=60). At the Osstell 1 measurement there was no significant association between primary stability and implant survival (P<0.753). In Osstell 2, however, the association was significant (P<0.001). CONCLUSIONS Only secondary stability RFA values were able to significantly predict implant outcomes, but not primary stability values. There was a good correlation between RFA and the proposed clinical classification of primary stability.

Surgical protocols for early implant placement in post‐extraction sockets: a systematic review

OBJECTIVES The aim of this systematic review was to evaluate the best timing for placing implants after tooth extraction, by comparing early vs. delayed implant placement and evaluating the hard and/or soft tissue ridge dimensional changes and the outcomes related with implant survival and prosthesis success. MATERIAL AND METHODS An online search of the main databases including The National Library of Medicine (MEDLINE via Pubmed), Embase and The Cochrane Central Register of Controlled Trials was conducted up to February 2011. Randomized controlled clinical trials (RCTs), prospective cohort studies and case-control retrospective studies, with a follow-up of at least 1 month after loading of dental implants, comparing: (i) early vs. delayed implant placement, (ii) augmentation vs. no augmentation at implant placement in early placed implants and/or (iii) the comparison of various augmentation procedures at early implant placement, were conducted. A hand search of relevant journals was also performed. Screening of eligible studies, assessment of their methodological quality and data extraction were conducted in duplicate by two independent reviewers. Authors of studies were contacted for clarification or missing information. RESULTS Eight studies were included, although meta-analysis could only be performed with the data from two studies comparing early vs. delayed implant. The percentage of bone height and bone width reduction favoured the early placement, with pooled mean difference between groups of 13.11% (95% CI: from 3.83 to 22.4; P = 0.057) and 19.85% (95% CI: from 13.85 to 25.81) respectively. Implant survival demonstrated a non-significant higher implant survival rate for the early group (RR = 1.02, 95% CI: 0.96-1.1).With regard to patient satisfaction, statistically significant differences between the groups in favour of the early group for overall satisfaction and appearance with the restoration were demonstrated at 2 years, although these differences were lost at 5 years. CONCLUSIONS Placement of dental implants at an early timing after tooth extraction may offer advantages in terms of soft and hard tissue preservation, when compared with a delayed protocol. Nevertheless, well-designed, high quality, randomized clinical trials, are needed, because the available evidence is today limited in terms of available studies and quality.

KPG index versus OPG measurements: a comparison between 3D and 2D methods in predicting treatment duration and difficulty level for patients with impacted maxillary canines.

Aim. The aim of this study was to test the agreement between orthopantomography (OPG) based 2D measurements and the KPG index, a new index based on 3D Cone Beam Computed Tomography (CBCT) images, in predicting orthodontic treatment duration and difficulty level of impacted maxillary canines. Materials and Methods. OPG and CBCT images of 105 impacted canines were independently scored by three orthodontists at t 0 and after 1 month (t 1), using the KPG index and the following 2D methods: distance from cusp tip and occlusal plane, cusp tip position in relation to the lateral incisor, and canine inclination. Pearsons coefficients were used to evaluate the degree of agreement and the χ 2 with Yates correction test was used to assess the independence between them. Results. Inter- and intrarater reliability were higher with KPG compared to 2D methods. Pearsons coefficients showed a statistically significant association between all the indexes, while the χ 2 with Yates correction test resulted in a statistically significant rejection of independency only for one 2D index. Conclusions. 2D indexes for predicting impacted maxillary canines treatment duration and difficulty sometimes are discordant; a 3D index like the KPG index could be useful in solving these conflicts.

Biological complications and peri‐implant clinical and radiographic changes at immediately placed dental implants. A prospective 5‐year cohort study

OBJECTIVES To evaluate clinically and radiographically immediate implants 5 years after insertion and to compare them with delayed-placed implants in the same subjects. MATERIAL AND METHODS Twenty-two consecutive patients that needed at least two implants for replacing hopeless teeth, one immediately upon extraction and the other in a delayed fashion (at least 4 months post-extraction) were selected in this prospective cohort study. Post-extraction immediate implants (II) and delayed implants (DI) groups were defined. One and 5 years after implant loading, clinical and radiographical outcome variables were recorded and analysed both at site and at implant level. Intra-group and inter-group comparisons were performed. RESULTS The intergroup comparison did not show significant differences for plaque index, bleeding on probing and suppuration. These parameters worsen in both groups along the study. This trend was stronger for the plaque index in the group II, which increased from 15.6% at 1 year to 25.9% at 5 years (P < 0.04). One year after loading, the sites with probing depth ≥5 mm were higher for the group II compared to DI (2.5% vs. 0%; P = 0.049). At the end of the study, no significant statistical differences were found. Radiographically, bone crestal changes did not yield significant differences. During the follow-up period, 25% of the implants (26.4% in group II and 23.5% in DI) showed biological complications: mucositis (20%) and/or periimplantitis (5.8%). No differences between groups were found. CONCLUSIONS Within the same patients, the implants placed with the immediate protocol demonstrated a higher tendency to crestal bone loss and to peri-implantitis, although these differences were not statistically significant.

Biochemical markers of bone metabolism in gingival crevicular fluid during early orthodontic tooth movement

OBJECTIVE To evaluate the expression of an activator of nuclear factor-kappa (RANK), osteoprotegerin (OPG), osteopontin (OPN), and transforming growth factor ß1 (TGF-ß1) in gingival crevicular fluid (GCF) of teeth subjected to orthodontic forces. MATERIALS AND METHODS A randomized, pilot clinical trial including 10 healthy volunteers was conducted using a split-mouth design. Orthodontic elastic separators were placed between the second premolar and first molar, with the contralateral quadrant serving as a control. The GCF samples were collected from the tension and compression sites at baseline, 24 hours, and 7 days after the placement of separators. The GCF sample volumes were measured using a Periotron 8000, and total protein concentrations were determined. Levels of RANK, OPG, OPN, and TGF-ß1 were also analyzed using a multiplex enzyme-linked immunosorbent assay. RESULTS The control sites remained unchanged throughout the study. In contrast, the concentration of OPG significantly decreased at the compression site by 24 hours, and the amount and concentration of RANK differed significantly between the control, compression, and tension sites after 7 days. A significant increase in absolute TGF-ß1 levels was also detected at the compression site versus the control and tension sites after 7 days. CONCLUSION Bone metabolism is affected by application of force to the teeth by elastic separators. Both increased expression of bone resorptive mediators (eg, RANK and TGF-ß1) and decreased expression of a bone-forming mediator (eg, OPG) on the compression side were detected.

Effects of probiotics in periodontal diseases: a systematic review

ObjectivesThis study was designed to determine the effects of probiotics in prevention and/or treatment of periodontal diseases.Materials and methodsWe performed broad searches in the MEDLINE, Embase, and Cochrane databases and selected articles that satisfied the description of randomized clinical trials comparing the administration of probiotics versus placebo or another intervention to prevent or treat periodontal diseases in adult patients.ResultsFour randomized clinical trials were analyzed in the final review process. For the primary outcome, probing pocket depth, there would be no clinical beneficial effect of probiotics. For secondary outcomes, probiotics have shown small benefits on plaque index and gingival inflammation.ConclusionsBased on the results of this review, the effectiveness of probiotics on the prevention and treatment of periodontal diseases is questionable. There is currently insufficient evidence demonstrating the benefits of systematic preventative use of probiotics in patients with periodontal diseases.Clinical relevanceThe use of probiotics are described to prevent or treat periodontal diseases in some clinical trials; therefore, a systematic review of the evidence for the effect of periodontal diseases is needed.

Ex vivo measurement reliability using two different cbct scanners for orthodontic purposes

There are many cone beam computed tomography (CBCT) scanners available on the market: detector technology, algorithm precision, and scanner settings influence image quality. The aim of this study was to compare the accuracy of linear measurements made on images of the same sample obtained using two different CBCT scanners.

Activity of jaw muscles in unilateral cross-bite without mandibular shift

OBJECTIVES To evaluate and compare electromyographic activity of jaw muscles at rest and during maximal voluntary clenching in maximal intercuspation between growing individuals with unilateral posterior cross-bite without functional mandibular lateral shift during closure and matched individuals with normal occlusion. These findings may help elucidate the impact of this occlusal condition on jaw muscle function and the therapeutic implications. DESIGN 30 growing children (10-12 years) with unilateral cross-bite without functional mandibular lateral shift during closure (cases) and 30 age- and sex-matched children with normal occlusion (controls) were consecutively selected applying highly restrictive criteria. Electromyographic activity coming from the areas of right and left anterior temporalis, posterior temporalis, masseter, and supra-hyoid muscles was evaluated at rest and during clenching. The asymmetry index was calculated for each muscle area to quantify the degree of asymmetry between sides. The masseter/anterior temporalis ratio during clenching was also recorded. RESULTS No significant differences were found between groups at rest. During clenching, activity of the cross-bite side masseter area was significantly lower in cases versus controls but no difference was found between cross-bite and non-cross-bite sides of this muscle. CONCLUSIONS Unilateral posterior cross-bite without functional mandibular lateral shift is associated with a lower electromyographic activity of masseter muscle area of the cross-bite side during maximal clenching in maximal intercuspation, compared to the children with normal occlusion. This result could suggest a functional adaptation that should be carefully considered. Long-term studies are needed to determine future repercussions and to evaluate the benefit of an early treatment.