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.

Static and fatigue resistance of two types of implant/abutment connectors.

The aim of this study is to determine in an experimental way through mechanical tests the static, fatigue and torque resistance of two types of implant/abutment connectors with diameters of 3.4–5.2 mm.

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.

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.

The use of various biomaterials in computer-guided crestal sinus lift procedures. A report on two case studies with volume comparison.

PURPOSE: In the context of the transcrestal maxillary sinus lift a wide variety of biomaterials have been used to fill the subantral space over the years. In this study, two types of biomaterials were used in order to fill the maxillary sinus: a nano-crystallized hydroxyapatite in an aqueous solution and a micronized heterologous bone in a collagen matrix. MATERIALS AND METHODS: The surgical procedures were designed and carried out using computer-guided surgery. The filling volume obtained was measured with a comparative software program. RESULTS: A ≥ 6 millimeter augmentation of osseous volume was obtained. This result is comparable to those obtained in lifts where conventional techniques were applied. The technique used was very precise and the difference between the projected and clinical outcome of the implant position had an average of less than 0.3 millimeters. CONCLUSIONS: This technique allows for the surgery to be performed in a way which is both minimally traumatic and invasive, and represents a viable alternative to those surgical techniques for crestal sinus lift currently in use.

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.

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.

CRESTAL SINUS LIFT USING A FLUIDO-DYNAMIC COMPUTER GUIDED PRECISE AND ATRAUMATIC TECHNIQUE.

One of the most frequent reasons for failure during the maxillary sinus floor lift operation is connected to the possibility of a rupture of the Schneiderian membrane which, if lacerated, cannot perform the function of graft containment. In order to reduce the incidence of complications it is necessary to cut the hard tissue with extreme accuracy and as little trauma as possible, while saving the soft tissue. The precision of pre-operation measures obtained through endoral x-rays, dental-scans and cone-beam CT allows us to approach and cut with delicacy the sinus cortical floor. The recent development of computer guided surgery gives the possibility of planning the operation, which reduces the risk of failure. The cortical of the maxillary sinus is reduced through the use of calibrated burs and a profiler to obtain a hole that enables both access to the maxillary sinus and, subsequently, the lifting of the Schneiderian membrane. Each stage of the operation is monitored and all the devices used pass through a custom-made template, which acts as a surgical guide. The sinus was filled using fluid biomaterial distributed through a dispenser, which had been created specifically for this technique. Due to the reduction in trauma and the fact that the process is much less invasive, this technique could be a valid alternative to the techniques known and carried out to date. Work time is reduced to less than 3 minutes in the cortical thinning operation and percussive trauma is avoided.

Detection of lymphotropic herpesvirus DNA by polymerase chain reaction in cerebrospinal fluid of AIDS patients with neurological disease.

Cerebrospinal fluid (CSF) samples from 49 acquired immunodefficiency disease syndrome (AIDS) patients with a central nervous system (CNS) disease were examined by polymerase chain reaction (PCR) to evaluate the association between the positivity for cytomegalovirus (CMV) and Epstein-Barr virus (EBV), and clinical diagnosis of a CNS disease. Frequency and clinical relevance of detection of DNA of human herpesviruses 6 (HHV-6), 7 (HHV-7) and 8 (HHV-8) were also determined. DNA of one or more of the following viruses was found in 26 of 49 patients (53%): CMV in 16 (33%), EBV in 13 (27%), human herpesvirus 6 (HHV-6) in 2 (4%), human herpesvirus 7 (HHV-7) in 1 (2%), and human herpesvirus 8 (HHV-8) in 1 (2%). The CMV detection was significantly associated with encephalitis and peripheral neuropathy (7/16 vs. 2/33, p = 0.003), while EBV with primary CNS lymphoma (P-CNSL) (8/13 vs. 0/36, p < 0.0001). HHV-6 DNA was found in CSF of two patients with neuroradiological features suggestive of cerebral lesions. HHV-8 or HHV-7 DNA was detected in the CSF of patients with unexplained neurological symptoms. This study confirms that the PCR analysis of CSF is a valid tool for the diagnosis of neurological diseases associated with CMV and EBV. On the other hand, HHV-6, HHV-7 and HHV-8, instead, were rarely detected in CSF of AIDS patients and have certainly no correlation with the CNS disease found.

Cellular localization of human herpesvirus 8 in nonneoplastic lymphadenopathies and chronic interstitial pneumonitis by in situ polymerase chain reaction studies.

OBJECTIVES: To study the cellular localization of human herpesvirus 8 (HHV-8) in rare cases of HHV-8 infection from Italy that are associated neither with human immunodeficiency virus (HIV) infection nor Kaposi's sarcoma (KS). METHODS: The presence and distribution of HHV-8-infected cells was investigated by direct in situ polymerase chain reaction (PCR) in the lymph node tissues from 2 patients with reactive lymphadenopathies with florid follicular hyperplasia and increased vascularity and in the lung tissue from 1 patient with chronic interstitial pneumonitis. RESULTS: HHV-8 was localized in lymphoid and monocyte-macrophage cells scattered in the interfollicular regions of both lymph nodes but not in endothelial cells. In the lung tissue, HHV-8 was found in the inflammatory cells infiltrating the interalveolar interstitium, in endothelial cells of the pulmonary vasculature, and in rare pneumocytes. CONCLUSIONS: HHV-8 can infect nonneoplastic lymph nodes of immunocompetent subjects, and the distribution of infected cells outside of the germinal centers resembles that of Epstein-Barr virus (EBV)-infected cells in the lymph nodes in the course of infectious mononucleosis. Endothelial cells and pneumocytes may be a target of HHV-8 infection out of the KS setting, at least in the presence of a chronic inflammatory process.

Human herpesvirus-6 reactivation in a longitudinal study of two HIV-1 infected patients.

After primary infection, human herpesvirus-6 (HHV-6) persists in latent form and can be reactivated in immunocompromised subjects. A longitudinal study of HHV-6 infection was carried out in two HIV-1 seropositive patients to provide in vivo evidence of HHV-6 reactivation. Concomitant with a significant rise of anti-HHV-6 IgG detected by IFA, a transient increase of HHV-6 viral load was shown in PBLs by PCR. During HHV-6 reactivation it was also identified either cell-free HHV-6 by PCR in plasma or IgM antibody titers. HHV-6 reactivation was followed by a temporary decrease in CD4+ count and by a progressive dramatic loss of CD4+ during the following 18 months. HHV-6 strain characterization by PCR demonstrated that first patient (MM) initially showed the B variant, followed by reactivation and persistence of the A variant, while in the second (SG) only the A variant was detected. The evidence of HHV-6 reactivation suggests its involvement in immunologic damage underlying the disease.

Quantitation of HCV viraemia by branched DNA signal amplification in patients treated with alpha-interferon--a longitudinal study.

Using bDNA, the plasma viral load trend of HCV-infected patients undergoing IFN therapy was analyzed. Nine patients were enrolled, each assigned to one of three groups, based on IFN response as determined by ALT and AST level trend. HCV was genotyped using DEIA. Each patient's clinical stage was determined by liver biopsy analysis. In nonresponding patients elevated viral loads and biochemical parameters were observed. These values were not influenced by IFN treatment. In relapsed patients the cessation of IFN treatment increased viral load; this was associated with a rise in ALT and AST values. In responders ALT and AST levels remained normal; viral load was low. Patients with elevated HCV viral load showed a worsening in their liver histology during the follow-up period. These results confirm that plasma viral load is a good marker of biochemical change and disease progression.

Cisapride vs metoclopramide. An acute study in diabetic gastroparesis.

Radionuclide gastric solid-phase emptying was studied in 10 subjects with diabetic gastroparesis comparing the acute intravenous administration of cisapride (2.5, 5, 10 mg), placebo, and metoclopramide (10 mg). No hemodynamic or electrocardiographic changes were noted. While both cisapride and metoclopramide normalized impaired solid emptying, cisapride at its highest dosage (10 mg) resulted in significantly faster gastric emptying (P = 0.003) than metoclopramide. The effects of cisapride were dose related and correlated well (r = 0.48, P less than 0.01) with the plasma drug levels. Clinical studies of chronic oral usage must take into account the dose-related response and factors affecting blood levels.