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.

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.

Post extractive implant: evaluation of the critical aspects.

PURPOSE: Nowadays, implant supported prosthetic rehabilitation is a reliable procedure to replace compromised or untreatable teeth. The purpose of this review is to explore the concept of post extractive implant and the indications for clinical practice through an analysis of recent studies in the literature. All the main factors that could influence the outcome of this treatment will also be considered. MATERIALS AND METHODS: Focusing on the extraction-socket healing time, three different implant insertion protocols have been defined: Immediate implant placement (IIP), Early implant placement (EIP), Delayed implant placement (DIP). The entity of bone remodeling can be associated with different factors: three dimensional implant position, presence/absence of platform switching, absence of facial bony wall, inter implant/tooth distance. RESULTS: All the studies in literature agreed that implant primary stability is the main condition for a successful osseointegration of dental implants. Primary implant stability is influenced by many factors including local bone quality and quantity, implant macro-design, soft tissue conditions and rehabilitation, surgical technique, prosthetic load timing, oral hygiene. CONCLUSIONS: There is insufficient evidence in literature to determine possible advantages or disadvantages of IIP, EIP or DIP. Studies suggest that IIP and EIP may be at higher risks of implant failures and complications than delayed implants; on the other hand the aesthetic outcome might be better when placing implants just after teeth extraction.

Immediate loading implants: review of the critical aspects.

PURPOSE: Modern dentistry have witnessed, a rapid and continuing evolution. Concerning the implant-rehabilitation protocols, they have been redefined in order to satisfy patient's increasing expectations in terms of comfort, aesthetic and shorter treatment period. The purpose of this review is to explore the concept of implant immediate loading and the indications for clinical practice. All the critical aspects that could influence the outcomes of this treatment will also be considered. MATERIALS AND METHODS: Three protocols for implant load timing have been classified: immediate loading implants (ILI); early loading implants (ELI); and conventional loading implants (CLI). Two subclassifications point out the different loading modality: 1) Occlusal loading or Non-Occlusal loading, 2) Direct loading or Progressive loading. Micromovements have been considered, since the start of implant dentistry, one of the main risk for the success of osseointegration. The determinant and most accessible parameter to assess the primary stability is the implant insertion torque value. To achieve the necessary torque value to perform immediate loading, it is therefore important to evaluate the bone density at the implant site. Computerized tomography (CT) has been regarded as the best radiographic method to evaluate the residual bone. RESULTS: The clinical success of this technique is highly dependent on many factors: patient selection, bone quality and quantity, implant number and design, implant primary stability, occlusal loading and clinician's surgical ability. Among these, implant primary stability is undoubtedly the most important. CONCLUSION: Studies on ILI show that successful outcome can be expected, if the previous criteria are fulfilled. It seems that ILI demonstrate a greater risk for implant failure when compared to CLI, although the survival rates were high for both the procedures. The use of different surgical procedures, type of prostheses, loading times and have very different study designs. This lack of homogeneity limits the relevance of the conclusions that can be drawn.

A new implant-abutment connection for bacterial microleakage prevention: an in vitro study.

PURPOSE: The aim of our study is to evaluate the ability of a new type of implant (Konus Implant System®, Industrie biomediche e farmaceutiche, Italy) to isolate the internal of an implant-abutment connection from the external environment. MATERIALS AND METHODS: To identify the capability of the implant to protect the internal space from the external environment, the passage of genetically modified Escherichia coli across implant-abutment interface was evaluated. Implants were immerged in a bacterial culture for twenty-four hours and then bacteria amount was measured inside implant-abutment interface with Real-time PCR. RESULTS: Bacteria were detected inside all studied implants, with a median percentage of 18% for Porphiromonas Gingivalis and 19% for Tannerella Forsythia. CONCLUSION: The reported results are similar to previous work. Konus Implant System® showed bacterial leakage similar respect others implant systems (18% Porphiromonas Gingivalis, 19% Tannerella Forsitya versus 20% of Bicon© and Ankylos ® systems). In spite of the limits of our study, none two-piece implant system has been demonstrated to perfectly close the gap between implant and abutment.

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.

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.

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.

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.

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.

Upper full arch rehabilitation with sinus by-pass with tilted implants via tapered-threaded expanders in low density bone: a clinical trial.

PURPOSE: 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 present a case series of full-arch rehabilitations performed with this procedure named: Tilted Implant Expansion Osteotomy (TIEO). MATERIALS AND METHODS: 12 patients (5 males and 7 females, average age 58.5 ± 8.1 years) with totally or partially edentulous maxilla were enrolled in this study. For each patient 4 implants were placed, the anterior implants in the area of lateral incisors or canines while, the posterior implants, immediately in front of the maxillary sinus, with an inclined position. Adopting the aforesaid procedure, 48 cylindrical two-piece implants were placed, 24 of which were placed in tilted position, in order to by-pass the maxillary sinus. After a healing period of 6 months, the second stage surgery was performed. The cases were finalized by means of a hybrid metal-acrylic prosthesis. The post finalization follow-up was at 12 months. RESULTS: Survival rate was 100% since none 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. CONCLUSION: TIEO is a promising surgical procedure for full-arch rehabilitation of maxillary edentulous sites and represents a therapeutic alternative to sinus lift techniques.

Endoscopic retrieval of a dental Implant into the maxillary sinus: a case report.

PURPOSE: In this article the Authors show a safe and predictable technique to remove displaced implants from the maxillary sinus. MATERIALS AND METHODS: A 49-year-old female was referred, to this centre by a general dentist, for the retrieval of the ectopic dental implant. After a preliminary clinical and radiological evaluation of the case the surgical procedure was performed. A loco-regional anesthesia was carried out and then the Maxillary Sinus Retrieval Device (MSRD), proposed in this study, was inserted in the canine fossa, via a circular antrostomy 5,5mm wide, previous execution of a mucoperiosteal flap. The MSRD is a trocar, modified with a funnel-shaped cannula in order to allow the easy access of both an endoscope and a suction cannula or, in alternative, a straight forceps. The implant was easily found end retrieved thanks to the endoscopic control. The postoperative was uneventful and no nasal bleeding was reported by the patient. CONCLUSION: The Authors recommend the use of the MSRD in order to minimize the biological sacrifice consequent to the implant retrieval in the maxillary sinus.

Full arch rehabilitation in severe maxillary atrophy with palatal approach implant placement: a case report.

PURPOSE: The edentulous severely atrophic maxilla, as consequence of alveolar bone resorption and pneumatisation of the maxillary sinus, represents a serious limitation to the implant rehabilitation. Implants insertion via palatal approach (PA), in combination with relatively minimally invasive techniques aimed at increasing bone volume without the use of autologous bone harvesting is a valid alternative among the options for the rehabilitation of the upper jaw. CLINICAL CASE: In a 70-year-old female, with a severe maxillary atrophy, 6 spiral taper implants were placed with the PA, combined with the bilateral transcrestal elevation of both the sinus floors and nasal cavities; a further GBR, with resorbable pericardium membrane covering a termoplastic allograft associated to a xenograft, was performed. The second stage was performed after 6 months. Implant prosthetic functionalization was carried out in 4 months by placing the removable prosthesis in direct contact with the healing cup screws. After that period the case was finalized with a hybrid prosthesis. Clinical and radiographic follow-ups were carried out at 6 months and at one year after prosthetic finalization, during which no pathological signs were recorded. CONCLUSIONS: The PA implant insertion described by the Authors, combined with bone augmentation procedures, performed in the same stage, may represent a valid and reliable solution to rehabilitate maxillary edentulous patients.

Increasing volume of vestibular soft tissues in flapless implant surgery through a modified connective punch technique: a controlled clinical trial.

PURPOSE: The aim of this article is to make a comparative assessment between the modification of the soft-tissue profile, around the healing cap screws (HCSs), following both the traditional flapless surgery (TFS) and a new modified flapless surgery, named Modified Connective Tissue Punch (MCTP) technique. MATERIALS AND METHODS: 8 patients (3M and 5F) (mean age 54.25±11.247 years) were enrolled in this study. Sixteen two-piece implants were placed on upper jaws, 2 for each patient, 8 with TFS and 8 with MCTP technique. In each patient the implants were placed in edentulous areas, of 2 or 3 adjacent teeth long. MCTP technique was performed on the front implant site (FIS) while the TFS was performed on the rear implant site (RIS). All implants were inserted and covered with healing cap screws (HCSs). Alginate impressions were carried out at the moment of the surgery, at 1 month and 4 months post-operative. Plaster models were poured and subsequently digitally scanned, in order to measure the distance between the gingival outline and the free margin of the HCS. The recorded values were analyzed with the ANOVA test. RESULTS: The use of MTCP technique, in comparison to TFS, showed a significative better outcome, in terms of vertical increments, of gingiva, on the VS toward the HCSs, during the entire observation period (p = 0.000 for all). CONCLUSION: The Authors recommend the use of MCTP technique for a better vestibular soft tissue outcome in flapless implant surgery.

Endoscopic management of the schneiderian membrane perforation during transcrestal sinus augmentation: a case report.

PURPOSE: In this article the Authors describe a procedure aimed to restore under endoscopic control, the continuity, of the Schneiderian membrane (SM) incidentally teared during a sinus lift with transcrestal approach. MATERIALS E METHODS: In a 44-year-old male, due to aforementioned complication, the SM was gently detached via transcrestal approach, with a customized small ball burnisher, in order to facilitate the placement of a collagen sponge, to close the communication with the sinus, followed by the subsequent insertion of a graft material. All the procedure was endoscopically controlled and, considering the successful grafted area elevation, was simultaneously followed by implant placement. After 6 months the second stage was performed always under endoscopic control. RESULTS: The endoscopic view of the grafted area showed a dome-shaped elevation sited on the top of the implant, the SM was apparently normal with no signs of inflammation, the antrum was empty and normally functioning. Periapical X-rays were performed: immediately after the surgery; at both 14 days and 6 months post-operative; at 6 months post prosthetic finalization. The volume of the grafted area progressively decreased over the time while its radiopacity, on the contrary, gradually increased, as expected after graft integration and remodelling. The implant was submitted to no functional load for 4 months by means of a temporary screwable acrylic crown inserted on a peek abutment and then finalized with a cementable metal-ceramic crown on a preformed titanium abutment. CONCLUSION: The Authors recommend the use of endoscope to repair the SM incidentally teared during transcrestal sinus lift.

Guided bone regeneration via a preformed titanium foil: clinical, histological and histomorphometric outcome of a case series.

PURPOSE: The aim of this paper was to evaluate the histological and histomorphometric outcome of Preformed Titanium Foil (PTF) to perform Guided Bone Regeneration (GBR) in posterior mandibular atrophies. MATERIALS AND METHODS: 10 subjects (1 male; 9 females; mean age 58±11.37 years), with distal mandibular atrophies were selected to perform GBR by means of PTF, using a moldable allograft paste as graft material. The devices, made of a 0,2 mm thick pure titanium foil, were pre-shaped using stereolithographic models obtained from CT-scan of the patients' recipient site. In the second stage, performed at 6.7±2.33 months, 18 cylindrical two-piece implants were placed and the devices removed, at the same time bone biopsies were harvested. At 4 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. RESULTS: Survival rate (i.e. SVR) was 100% since none fixtures were lost. At the one-year follow up the clinical appearance of the soft tissues was optimal and not pathological signs on probing were recorded. The success rate (i.e. SCR) was 88.2% and the average peri-implant bone reabsorption was 1.17±0.41 mm. The average rate of graft contraction was 19.4±10.55%. The mean percentage occupied by mineralized bone was 48.03±5.93%, while the bone marrow and graft material were 36.1±2.81% and 15.87±4.87 %, respectively. CONCLUSION: The results suggest good potentialities of the method for GBR in distal mandibular atrophies, allowing to maximize the outcome and simplifying the surgical phase.

Polymerization shrinkage and spherical glass mega fillers: effects on cuspal deflection.

PURPOSE: The Authors analyzed the effect of spherical glass mega fillers (SGMF) on reducing contraction stress in dental composite resins, by means of a cavity model simulating the cuspal deflection which occurs on filled tooth cavity walls in clinical condition. MATERIALS AND METHODS: 20 stylized MOD cavities (C-factor = 0.83) were performed in acrylic resin. The inner surface of each cavity was sand blasted and adhesively treated in order to ensure a valid bond with the composite resin. Three different diameter of SGMF were used (i.e. 1, 1,5, 2 mm). The samples were divided in 4 groups of 5 each: Group 1 samples filled with the composite only; Group 2 samples filled with composite added with SGMFs, Ø1mm (16 spheres for each sample); Group 3 samples filled with composite added with SGMFs, Ø1,5 mm (5 spheres for each sample); Group 4 samples filled with composite added with SGMFs, Ø2 mm (2 spheres for each sample). Digital pictures were taken, in standardized settings, before and immediately after the polymerization of the composite material, placed into the cavities. With a digital image analysis software the distances from the coronal reference points of the cavity walls were measured. Then the difference between the first and second measurement was calculated. The data were analyzed by means of the ANOVA test. RESULTS: A significative reduction on cavity walls deflection, when the composite resin is used in addiction with the SGMFs was observed. The SGMFs of smallest diameter (1mm) showed the better outcome. CONCLUSION: The SGMFs are reliable in reducing contraction stress in dental composite resins.

Light diffusion through composite restorations added with spherical glass mega fillers.

PURPOSE: Evaluate how the spherical glass mega fillers (SGMFs) can positively interfere with light diffusion when incorporated in a composite restoration. MATERIALS AND METHODS: 30 samples (Ss) were performed, applying 2 composite layers of 3 mm each: 6 were made with composite only; 6 with a layer of SGMFs of O1.5mm within the first layer of composite; 6 with 2 overlapping layers of SGMFs of O1.5mm; 6 with a layer of SGMFs of O2mm; 6 with 2 overlapping layers of SGMFs of O2mm. The curing time was set at 40s for the first layer, and 120s for the second layer, transilluminated through the first layer. Digital pictures were taken, in standardized settings, during the transillumination, and the light intensity was measured with a digital image analysis software. RESULTS: From a lateral view the Ss with a single layer of SGMFs of O1.5mm and O2mm, the relative increments of light intensity, were of 24.37% and 33.33% respectively. Concerning the Ss made with 2 layers of SGMFs, the relative increments were of 67.99% and 66.4% respectively. In front view has emerged a relative increase rate of light intensity of 53.66% and 79.58%, in the Ss with a single layer of SGMFs of O1.5mm and of O2mm respectively. Furthermore, in the Ss with two layers of SGMFs of O1.5mm and O2mm the relative increments were of 267.53 and 319.63% respectively. CONCLUSION: The SGMFs are reliable in facilitating light diffusion within the light-curing composite resins.