Preventive contamination with Lactobacillus reuteri of the implant-abutment connection: an in vivo study.

The aim of this study is to preventively contaminate the abutment-fixture connection (AFC) with Lactobacillus reuteri(L. reuteri), to evaluate the presence of micro leaks in different types of implant-abutment connections, by measuring the concentration of (L. reuteri), in the sulcular fluid over time. This microorganism produces the Reuterine, an antibiotic which counteracts the development of other microbial species. Fourteen biphasic implants were placed on 10 patients (3 women; 7 men; mean age 55.9±16.54y). Eight implants had a flat top connection (internal Hex) while six implants had a tapered connection (conical plus octagonal). At the time of prosthetic finalization, before the healing screw was removed, the sulcular fluid was harvested, on each implant, by means of three sterile paper cones placed into the gingival sulcus and left in place for 20 sec before to be transferred to a sterile tube. Once the healing screw has been removed, first the implant connection has been gently dried with air jet for 10sec and then completely filled with (L. reuteri) DSM 17938 (Reuflor, Italchimici, Italy). Immediately after the prosthetic finalization the sulcular fluid was then harvested again, with the same procedure described before and repeated at 1 week and 1 month of follow up. The samples were then sent for subsequent DNA extraction and real-time PCR. Our results demonstrate that the concentration of (L. reuteri), in the sulcular fluid, does not persist over time in case of preventive contamination of the AFC, demonstrating no significative differences between flat top and tapered connections. Therefore, the use of the latter does not lead to a lower risk of Peri Implant Disease (PID). Long-term studies, involving a larger number of samples, are advisable to confirm these findings.

Clinical applications of Natural Bone Morphoproteins in dentistry: a narrative review.

The need to restore bone loss in maxilla and mandible has led to find natural bone substitutes, such as fresh autogenous bone grafts. Fresh autogenous bone grafts (FABGs) have a remarkable capacity to induce new bone formation, a phenomenon called ‘osteoinduction.’ FABGs are useful in craniomaxillofacial and oral applications to restore bone deficiencies. The isolation of those proteins believed to be responsible for the osteoinductive activity of FABGs, namely Natural Bone Morphogenetic Proteins (NBMPs), led to a new era in bone regeneration. NBMPs have been approved for use in specific oral and maxillofacial applications. Clinical trials and studies of oral and craniofacial surgery have indicated that NBMPs can promote bone repair. Information about the biology, chemistry, and actions of NBMPs has called into question whether NBMPs would result in clinically useful bone induction and morphogenesis. Preclinical and specific clinical trials have indicated the efficacy of NBMPs either combined with autograft or compared with an autograft alone. In light of questions about potency and safety of NBMPs, however, additional high-level evidence is needed for specific clinical indications and appropriate patient populations that would benefit from their use.

Mechanical, chemical and biological aspects of titanium and titanium alloys in implant dentistry.

Implant dentistry has become a popular restorative option in clinical practice. Titanium and titanium alloys are the gold standard for endo-osseus dental implants production, thanks to their biocompatibility, resistance to corrosion and mechanical properties. The characteristics of the titanium implant surface seem to be particularly relevant in the early phase of osseointegration. Furthermore, the microstructure of implant surface can largely influence the bone remodelling at the level of the bone-implant surface. Recently, research has stated on the long-term of both survival and success rates of osseointegrated implants and mainly on biomechanical aspects, such as load distribution and biochemical and histological processes at the bone-implant interface. This short review reports recent knowledge on chemical and mechanical properties, biological aspects, innovations in preventing peri-implantitis, describing clinical applications and recent improvements of titanium dental implants. In addition, it highlights current knowledge about a new implant coating that has been demonstrated to reduce the number of initially adhering bacteria and peri-implantitis.

Computer-guided implant insertion in a patient with impacted maxillary canines: case report.

The use of minimally invasive surgical techniques undoubtedly represents a huge advantage for both the clinician and the patient. This case report shows the possibility of making an implant-prosthetic rehabilitation in an upper jaw in a patient who presented dental elements 1.3 and 2.3 in bone inclusion. The use of computer-guided surgery offers us the possibility to carry out this type of implant rehabilitation without performing the extraction of the above-mentioned dental elements combined with the bone regeneration of the extraction sockets. Consequently, surgery invasiveness and post-surgery complications are reduced to a minimum. Additionally, the predictability of the methodology is evaluated with specific software that enables a comparison between what is virtually planned and what occurs in clinical practice.

Cement layer thickness and shear stress resistance in cylindrical dowel spaces: pull-out test.

PURPOSE: This study evaluated the effects of different dowel space (DS) diameters on pull-out bond strength of a cylindrical post, of threaded steel, to dentin. MATERIALS AND METHODS: Forty-five extracted human teeth were divided in 3 groups with DSs, with the same depth (6 mm), differing for the diameter (i.e. 1.5 mm, Group 1; 1.75 mm, Group 2; 2.00 mm, Group 3). Both the diameter of the post (1.3 mm) and the composite resin cement (Panavia 21) were the same for all the samples. The samples were submitted to pull-out test by means an Universal Testing Machine (Mod. 1193, Instron) (1KN load cell, crosshead speed 0.5 mm/min). RESULTS: The mean values of the bond strength (BS) were: Group 1, 442±128.3N; Group 2, 411.3±111N; Group 3, 448.7±142.29N. While the calculated average shear bond strengths (SBSs) were: Group 1, 14.7±4.27MPa; Group 2, 11.6±3.14MPa; Group 3, 11±3.5MPa. ANOVA test showed not significative differences, among the groups, concerning the BS: Group 1 vs Group 2 (p = 0.490); Group 1 vs Group 3 (p = 0.894); Group 2 vs Group 3 (p = 0.431). Significative differences were observed, among the groups, concerning the SBS for Group 1 vs Group 2 (p = 0.032) and Group 1 vs Group 3 (p = 0.014). While a not significative difference was found, concerning this parameter, for Group 2 vs Group 3 (p = 0.641). CONCLUSION: The cement thickness can influence the SBS of the adhesively luted posts, in our setting, the best values were obtained with a thickness of 100 µm.

Clinical and histomorphometric outcome in future site development performed with a nano-hydroxyapatite through hydraulic sinus lift technique.

PURPOSE: The crestal sinus lifting by means of hydraulic technique associated with a nano-cristalline hydroxyapatite in an aqueous medium is investigated. MATERIALS AND METHODS: A specific purpose-made instrument is used, consisting of a syringe with a micrometrically controlled piston connected to a dispenser used to inject, in a calibrated and precise manner, noted volumes of graft material into the sub-schneiderian space. Adopting such a technique the Authors performed 7 future site developments, on 7 patients (2 males; 5 females; mean age 49.29±8.08 years), using a nanocrystalline hydroxyapatite. In the second stage, performed at 5.71±1.52 months, 7 implants were placed, after harvesting bone biopsies from the regenerated sites. The samples underwent histological and histomorphometric analysis. RESULTS: The average percentage of vital bone was of 33.27±5.98%, while the bone marrow and graft material were 60.84±5.93% and 5.87±3.05%, respectively. CONCLUSIONS: The results confirm the effectiveness of this method in restoring bone volume in the sub-antral region. Furthermore nano-cristalline hydroxyapatite is a proper material for sinus floor augmentation.

Diffusion of light through quartz fiber-reinforced epoxy resin double taper posts.

PURPOSE: The aim of this study was to evaluate the progression of the light through a series of translucent posts available on the market (D.T. Light-post, R.T.D.). MATERIALS & METHODS: nine D.T. Light-posts (DTLPs) were analyzed, 3 for each available measure. Each post was trans-illuminated both in vertical trans-ilumination (VTI) and oblique trans-illumination (OTI), via a light curing unit (LCU) (V.I.P., Bisco), in complete darkness conditions, and the resulting image of the post, was digitally acquired with a 1:1 ratio. The images were then analyzed using digital image analysis software (Image Pro plus 4.1, Media Cybernetics) previously performing the light intensity calibration, of the LCU, by means a radiometer (Curing Radiometer model 100, Demetron Corp.). The evaluation of the progression of the light through the posts was conducted for each post along its longitudinal axis. RESULTS: no significant differences concerning VTI vs OTI for DTLP n.1 (p = 0.341) and DTLP n. 3 (p = 0.115), while for DTLP n.2 a significant difference was observed (p = 0.041); Conclusion: The results demonstrate that the greater the section of the post, the greater its ability to transmit light at a distance; also the vertical Trans-illumination of the post is to be preferred to the oblique one.

Clinical outcome of a two-piece implant system with an internal hexagonal connection: a prospective study.

The purpose of this prospective clinical study was to evaluate the survival rate (SVR - i.e. fixtures still in place at the end of the observation period) and success rate (SCR - i.e. bone resorption around implant neck) of an implant system characterized by cylindrical and tapered implants, both provided with an internal hexagonal connection. In the period between January 1996 and October 2011, 52 implants with internal hexagonal connection were inserted in 21 females and 31 males, mean age 54±11 years. The mean post-surgical follow-up was 44.6±34.4 months. Several parameters were evaluated as potential outcome conditioners: age, gender, smoking, replaced tooth, periodontal disease, fixture shape (i.e. cylindrical or tapered), jaw location (i.e. maxilla or mandible), bone graft, immediate loading, post-extractive placement, type of prosthesis (i.e. single crown or bridge), edentulism, implant diameter and length. An SPSS statistical program was used and Cox regression analysis performed. SVR was 100% since no fixtures were lost. SCR, expressed through the mean marginal bone loss, was 77%. No significant differences were found, for most of the parameters analyzed, with the exception of prosthetic bridges, where implants supporting this type of rehabilitation showed a worse clinical outcome in comparison to single crown rehabilitations. Internal hexagonal connection is a reliable tool for oral rehabilitation.

Maxillary sinus by-pass with tilted implants via tapered-screw bone expanders in low density bone: one year follow -up of a case series.

In the present paper the use of tapered-screw bone expanders (TSBEs) is proposed, in combination with the placement of tilted implants in close proximity to the anterior sinus wall, solving the problem of the reduced height of the alveolar bone in the sub-antral area. The Authors named the procedure: Tilted Implant Expansion Osteotomy (TIEO). Fifteen patients (10 females and 5 males, mean age 47.8±8.15 years) with distal edentulous maxillae were enrolled in this study. For each edentulous site 2 implants were placed, the anterior implant in the area of the most anterior missing tooth while, the posterior implant, immediately in front of the maxillary sinus, with an inclined position. Adopting the aforesaid procedure, 34 cylindrical two-piece implants were placed, 17 of which were placed in tilted position, in order to by-pass the maxillary sinus. After a healing period of 4-6 months, the second stage surgery was performed. The cases were finalized by metal-ceramic cementable restorations with a variable number of elements, from 2 to 4, without any cantilever element. The post finalization follow-up was at 12 months. Survival rate was 100% since no fixtures were lost. At the one-year follow-up the clinical and radiological appearance of the soft and hard tissues was optimal and no pathological signs were recorded. TIEO is a promising surgical procedure for oral rehabilitation of maxillary edentulous sites and represents a therapeutic alternative to sinus lift techniques.

A prospective evaluation of outcomes of two tapered implant systems.

The purpose of this prospective clinical study was to evaluate survival rate (SVR - i.e. fixtures still in place at the end of the observation period) and success rate (SCR - i.e. bone resorption around the implant neck) of two tapered implant systems. Both systems were equipped with a tapered connection, one requiring bone-level (BL) placement, while the other required soft-tissue-level (STL) placement. In the period between January 1996 and October 2011, 133 fixtures were inserted, 90 in females and 43 in males, with a mean age of 60±11 years. The mean post-surgical follow-up was 64±38 months. Several clinical parameters were evaluated as potential outcome conditioners. An SPSS program was used for statistical analysis and a Cox analysis was performed. The SVR was 100% since no fixtures were lost. SCR, expressed through the mean marginal bone loss, was 88%. No significant differences were found, for most of the variables investigated with the exception of bone grafting and implant type: STL implants showed a better clinical outcome than BL implants when bone grafting was performed simultaneously with implant placement. Tapered implants are reliable devices for oral rehabilitation of jaws.

Endoscopically controlled hydraulic sinus lift in combination with rotary instruments: one-year follow-up of a case series.

The aim of this study was to evaluate a sinus lift via crestal approach (SLVCA) case series, performed with rotary instruments and hydraulic pressure, analyzed under endoscopic control. Sixteen patients (11 female, 5 male, mean age 47.13±8.07 years) candidates for SLVCA were enrolled in this study. Twenty-two cylindrical two-piece implants were placed. After a suitable period of time needed for the consolidation of the graft (mean value 5.78±1.49 months), the bone augmentation was assessed by means of intraoral X-ray exams before the surgical procedure of re-entry. After a functional load with temporary acrylic fixed prosthesis, on Peek abutments, for a span of 4 months, the cases were finalized with cemented metal-ceramic prosthesis (10 single crowns, 6 bridges). The post finalization follow-up was at 12 months. During the perforation of the sinus floor via rotary instruments no perforations of the sinus membrane were observed either during the hydraulic detachment or simultaneous filling of the subantral space with the graft material. Survival rate was 94.5% since one fixture was lost, but immediately replaced with a new one. At the one-year follow-up the clinical and radiological appearance of the soft and hard tissues was optimal and no pathological signs were recorded. The SLVCA performed with rotary instruments and hydraulic pressure is a reliable grafting procedure for oral rehabilitation of maxillary edentulous sites.

Guided bone regeneration by means of a preformed titanium foil: A case of severe atrophy of edentulous posterior mandible.

The aim of this case report was to evaluate the potential of preformed titanium foil (PTF) as membrane, used together with a mouldable allograft paste, for guided bone regeneration in a case of severe mandibular posterior atrophy involving the alveolar nerve. In order to create a rigid barrier to the competitive growth of soft tissues and a stable volume for the colonization of the osteoprogenitor cells, a foil of pure titanium was pre-shaped by means of a stereolithographic model, obtained from a CT-scan of the patient. This procedure showed promising results, allowing to maximize the outcome and simplifying the surgical phase.

Modified connective tissue punch technique to increase the vestibular/buccal keratinized tissue on flapless implant surgery: a case series.

The aim of this article is to show a simple and predictable technique to enhance both the vestibular/buccal (V/B) gingival thickness (GT) and keratinized tissue width (KTW) improving the soft-tissue profile after flapless implant placement. The technique proposed was named Modified Connective Tissue Punch (MCTP). Fourteen patients (6 men and 8 women) aged between 35 and 69 years (mean value 48.07±13.023 years) were enrolled in this case series. Seventeen implant sites were submitted to flapless procedure. The connective punch (CP) was harvested with a motor-driven circular tissue punch and then a full-split dissection was executed, in order to create a deep pouch, beyond the mucogingival junction, on the V/B side. In this recipient site the CP was placed. The normal flapless surgical protocol was used; implants were inserted and covered with transgingival healing cap screws. GT and KTW were measured: both immediately before and after surgery; at the time of the prosthetic finalization (3-4months, respectively, for mandible and maxilla); 1 year post surgery follow-up. GT was measured at 1 mm, 2 mm and 5 mm on the V/B side, from the outline of the punch. Both KTW and GT at 1 and 2 mm can be effectively increased, while no significant effects for GT at 5 mm can be expected from this technique. Furthermore, the mean values of KTW and GT at 1 mm and 2 mm show significant increases at 3-4 months post-operative, while no further significant increments are shown at 1 year post-operative follow-up. The Authors recommend the use of the MCTP technique to reduce the number of aesthetic complications and soft tissue defects in flapless implant surgery. Longer follow-ups are needed to evaluate the stability of peri-implant tissues over time.

Retrospective study on bone-level and soft-tissue-level cylindrical implants.

The purpose of this prospective clinical study was to evaluate the survival rate (SVR - i.e. fixtures still in place at the end of the observation period) and success rate (SCR - i.e. bone resorption around implant neck) of two cylindrical implant systems. Both systems were equipped with a tapered connection, one requiring a bone-level (BL) placement, while the other a soft-tissue-level (STL) placement. In the period between January 1996 and October 2011, a total of 150 implants (76 in females and 74 in males, mean age 60±11 years) were inserted. The mean post-surgical follow-up was 84±47 months. Several parameters were evaluated as potential outcome conditioners: age, gender, diabetes, smoking, periodontitis, type of edentulism, replaced tooth, jaw location (i.e. maxilla or mandible), bone graft, immediate loading, post-extractive, type of prosthesis, implant diameter and length. An SPSS program was used for statistical analysis. Only two fixtures were lost, therefore SVR was 98.7%. SCR, expressed through the mean marginal bone loss, was 92%. The mean peri-implant bone loss was 0.121.47 mm for BL implants and 0.041.3 mm for STL implants. None of the studied variables had a statistical significant impact on SVR or SCR. Cylindrical implants are reliable for oral rehabilitation.

The influence of “conical plus octagonal” internal connection on implant survival and success rate: a retrospective study of 66 fixtures.

Implant oral rehabilitation has become one of the most successful dentistry techniques over the last 30 years. However, peri-implantitis is the most important complication in implant dentistry. Peri-implantits can be caused by inadequate implant-abutment connections (IAC). The aim of our study is to evaluate the influence of “conical plus octagonal” (i.e. I-Fix connection) on implant survival and success rate. All the implants included in this study were of a completely new type (I-Fix implants and abutments by FMD Falappa Medical Devices S.p.A. Rome, Italy). Sixty-six implants were inserted in males and females. The implants were of different diameters and lengths, inserted both in the mandible and in the maxilla with immediate or delayed loading, with guided bone regeneration (GBR), and post-extractive surgery. All implants were provided with I-Fix connection, 64 abutments using passing screws and 2 using full screws. None of the 66 implants were lost (i.e. survival rate - SVR = 100%). Cox-regression analysis demonstrated that diabetes (p=0.0074), GBR (p=0.0115), maxilla (p=0.0117) and smoking (p=0.0194) have a statistical significant impact on clinical outcome (i.e. greater bone resorption around implant neck). Our data show that I-Fix connection did not influence SVR. This finding demonstrates that I-Fix design seemed to significantly affect the survival rate of the implants in a recent meta-analysis. In spite of the limits of our study, I-Fix connection has been demonstrated to be efficient in closing the gap between implant and abutment and maintaining a good connection over time.

Prevention of bacterial leakage at implant-abutment connection level: an in vitro study of the efficacy of three different implant systems.

Peri-implantitis is the main cause of implant failures. Peri-implantitis is provoked by the presence of bacterial infiltration around Implant-Abutment Connection (IAC). Reduction of bacterial leakage may be achieved by improving the accuracy and precision of the two pieces of IAC. The aim of the present in vitro study was to evaluate bacterial microleakage from the inside to the outside of the IAC, testing the efficacy of three new designs of internal conical connection (FN - nano-fix -, NQ - uNiQo - and Elisir implant systems by FMD, Rome, Italy). To identify the efficacy of three new IAC, the passage of genetically modified Escherichia coli across IAC was evaluated. A total of 17 implants were used (5 FN, 6 NQ and 6 Elisir). All implants were immerged in a bacterial culture for 48 h and bacteria amount was then measured inside and outside IAC with Real-time PCR. Bacterial quantification was performed by Real-Time Polymerase Chain Reaction using the absolute quantification with the standard curve method. In all the tested implants, bacteria were found in the inner side, with a median percentage of 1.9% FN, 1.4% NQ and 2.6% Elisir. The analysis revealed that in both cases (internally and externally), bacteria grew in the first 48 hours but subsequently started to die, probably due to nutrient consumption. Of the three, the most efficacious connection was NQ. Within the limitations of this study, it was concluded that the best implant connection reducing bacterial leakage al IAC level was NQ (NQ implant system by FMD, Rome, Italy).

Clinical outcome of 215 transmucosal implants with a conical connection: a retrospective study after 5-year follow-up.

The purpose of this retrospective clinical study was to evaluate the survival rate (i.e. SVR – fixtures still in place at the end of the observation period) and success rate (i.e. SCR - bone resorption around implant neck) of an implant system characterized by cylindrical and tapered implants, both types of implant being equipped with a conical connection with an internal octagon (COC), both implant types having a 1.8 mm smooth neck, positioned above the bone crest level. A total of 65 subjects received 215 COCs between January 1996 and October 2011. All COCs were placed and restored by three experienced dental surgeons. The mean follow-up was 84±44 months. The patients involved in the study were both male (30) and female (35), of whom 30 were smokers (less than 20 cigarettes/day) and none was diabetic. The implants differed in terms of diameter and length, and were inserted both in the mandible (97) and in the maxilla (118). Sixty-seven implants were single tooth rehabilitations, and 148 prosthetic bridges. Fourteen had guided bone regeneration (GBR), and 10 were placed in post-extractive sites. Forty of the implants were provided with passing-screw abutments and 175 with full-screw abutments. The data were analyzed using descriptive statistics. None of the implants failed before prosthetic restoration, resulting in an SVR=100% after loading. The radiographic and clinical data revealed well-maintained, hard and soft tissue around the COCs, with an SCR=92.6%. Cox regression analyses did not detect any variables with statistical impact on the clinical outcome. In conclusion, Shiner XT implants are reliable tools for oral rehabilitation.

Guided bone regeneration in distal mandibular atrophy by means of a preformed titanium foil: a case series.

The aim of this case series was to evaluate the clinical outcome of preformed titanium foil (PTF) to perform guided bone regeneration (GBR) in posterior mandibular atrophies. Thirteen patients (4 male; 9 female; mean age 58.85±10.16 years), with class II division C atrophy, according to Misch, were selected to perform GBR by means of PTF, using a moldable allograft paste as graft material. The devices, made of a 0.2mm thick pure titanium foil, were pre-shaped using stereolithographic models obtained from CT-scan of the patients’ recipient sites. In the second stage, performed at 6.35±2.15 months, 23 cylindrical two-piece implants were placed and the devices removed. At four months, the implants were exposed and submitted to progressive prosthetic load for a span of 4 months. The cases were finalized by means of metal-ceramic cementable restorations. The post finalization follow-up was at 12 months. Survival rate (i.e. SVR) was 100% since no fixtures were lost. At the one-year follow up, the clinical appearance of the soft tissues was optimal and no pathological signs on probing were recorded. The success rate (i.e. SCR) was 82.6% and the average peri-implant bone reabsorption was 0.99±0.59 mm. The results suggest good potentialities of this method for bone volume augmentation in distal mandibular atrophies, allowing to maximize the outcome and simplifying the surgical phase.

The use of resorbable cortical lamina and micronized collagenated bone in the regeneration of atrophic crestal ridges: a surgical technique. Case series.

Some graft materials, such as micronized and collagenated bone, have an excellent capacity to be reabsorbed, allowing for the reformation of good-quality bone, but do not have the mechanical characteristics that would allow for stability in terms of shape and size. In this study, a technique is proposed which makes use of resorbable cortical lamina in order to create recipient sites that can be filled with micronized collagenated bone paste. The adequate vascularization of the graft combined with the integration of the lamina, which does not need to be removed, makes it possible to propose this technique as a potential alternative to those used to date.

Non-ablative radio-frequency rejuvenation: a histological and bio-molecular report.

Radiofrequency machines for medical use are known to produce moderate clinical improvement of skin laxity without invasive procedures. Numerous equipment with different characteristics have been proposed after the introduction in 2002 of the first FDA approved device. This report is aimed to test if RF treatment is effective when performed at low frequency and low energy level. Two RF treatments were performed unilaterally 7 and 2 days before a planned eyebrow lifting surgery, with a radiofrequency device with 0.52 to 0.7 MHz frequencies, maximum energy of 200 W, used at 40% of its power. A bipolar handpiece with a diameter of 30 mm and a maximum power of 9-9.5 W was massaged along the temporal area for 10 min. Skin samples of treated and untreated sides were collected during surgery and processed for histologic examination and RT-PCR analysis, to test differences in gene activation in a panel of proteins that are relevant in extracellular matrix of dermal connective tissue. The histological examination of the samples showed that the treatment induced a loss of the typical oriented structure in the reticular dermis. The study through RT-PCR evidenced that ELN, the gene codifying for Elastine was strongly enhanced. Some collagen-tested genes (COL1A1, COL3A1 and COL9A1) were inhibited by the treatment, whereas COL2A1 and COL11 were activated. The genes responsible for Metallo-proteases (MMP) 2, 3 and 13 were depressed, while the MMP9 was stimulated. Gene codifying for Hyaluronic synthase 1 (HAS1), Hyluronidase 1 (HYAL1), Neutrophyl elastase (Elane), Desmoplakin (DSP) and GDF6 were inhibited. Insulin like growth factor (IGF1) gene activity was enhanced. RF treatment, with the tested non-ablative equipment, produced histological effects and change in DNA expression of some extracellular matrix related genes, confirming the biostimulatory role of this procedure.