Juliana Marotti

Recent advances of ultrasound imaging in dentistry – a review of the literature

Ultrasonography as an imaging modality in dentistry has been extensively explored in recent years due to several advantages that diagnostic ultrasound provides. It is a non-invasive, inexpensive, painless method and unlike X-ray, it does not cause harmful ionizing radiation. Ultrasound has a promising future as a diagnostic imaging tool in all specialties in dentistry, for both hard and soft tissue detection. The aim of this review is to provide the scientific community and clinicians with an overview of the most recent advances of ultrasound imaging in dentistry. The use of ultrasound is described and discussed in the fields of dental scanning, caries detection, dental fractures, soft tissue and periapical lesions, maxillofacial fractures, periodontal bony defects, gingival and muscle thickness, temporomandibular disorders, and implant dentistry.

Photodynamic Therapy Can Be Effective as a Treatment for Herpes Simplex Labialis

BACKGROUND DATA AND OBJECTIVE Herpes is a common infectious disease that is caused by human herpesviruses. Several treatments have been proposed, but none of them prevent reactivation of the virus. This article describes the use of photodynamic therapy (PDT) as a treatment for herpes lesions, and reports on four cases. MATERIALS AND METHODS PDT was used as an adjuvant therapy for the treatment of herpes labialis in four patients. A special type of 0.01% (m/V) of methylene blue solution was applied to the vesicular stage of herpesviral disease and the lesions were irradiated with laser energy (wavelength 660 nm, energy density 120 J/cm(2), output power of 40 mW, 2 min per point, 4.8 J of energy/point, at four points). After 24 h the patients returned and phototherapy was repeated with the same equipment, this time with 3.8 J/cm(2) and 15 mW, for a total dose of 0.6 J. The same procedure was repeated 72 h and 1 wk later. RESULTS Treatment with low-level laser therapy can be considered as an option in the treatment of herpes labialis, and decreases the frequency of vesicle recurrence and provides comfort for patients. No significant acute side effects were noted and the lesions healed rapidly. CONCLUSION Treatment of herpes labialis with PDT was effective, had no side effects, and when associated with laser phototherapy, accelerated the healing process.

Measurement of buccal bone volume of dental implants by means of cone-beam computed tomography

PURPOSE The aim of this study was to evaluate the accuracy of cone-beam computed tomography (CBCT) for measuring the buccal bone volume around dental implants. MATERIALS AND METHODS Three to six implants were inserted into the anterior maxilla of eight skulls, depending on the availability of bone, and after this, the CBCT was performed. By means of CBCT image, measurements of the bone wall at three points of the implant were obtained, analyzed and compared with those obtained in the plaster skull casting. RESULTS The results showed that for the three points of the implants, no statistically significant difference in the measurements was obtained from the plaster model and CBCT images. CONCLUSIONS CBCT can be a useful tool for assessing buccal bone volume along the implant.

High-Intensity Laser and Photodynamic Therapy as a Treatment for Recurrent Herpes Labialis

OBJECTIVE The aim of this study was to report the treatment of recurrent herpes labialis (RHL) using a high-intensity laser or methylene blue (MB)-mediated photodynamic therapy (PDT) in combination with low-level laser therapy (LLLT). MATERIALS AND METHODS Four clinical cases of patients diagnosed with RHL are described in this report. Two patients were subjected to high-intensity laser therapy (HILT) followed by LLLT, and two patients received MB-mediated PDT, again followed by LLLT. LLLT was conducted at 24, 48, 72 h, and 7 d after HILT or PDT. Patients were followed up after 6 mo. RESULTS Throughout the follow-up period, all patients reported pain relief and did not show any signs or symptoms of RHL. A favorable healing process was observed in all cases. None of the patients reported pain as a consequence of the treatment. CONCLUSION These results suggest that HILT and MB-mediated PDT, in combination with LLLT, may constitute a benefit when treating vesicles in RHL.

Laser treatment of recurrent herpes labialis: a literature review

Recurrent herpes labialis is a worldwide life-long oral health problem that remains unsolved. It affects approximately one third of the world population and causes frequent pain and discomfort episodes, as well as social restriction due to its compromise of esthetic features. In addition, the available antiviral drugs have not been successful in completely eliminating the virus and its recurrence. Currently, different kinds of laser treatment and different protocols have been proposed for the management of recurrent herpes labialis. Therefore, the aim of the present article was to review the literature regarding the effects of laser irradiation on recurrent herpes labialis and to identify the indications and most successful clinical protocols. The literature was searched with the aim of identifying the effects on healing time, pain relief, duration of viral shedding, viral inactivation, and interval of recurrence. According to the literature, none of the laser treatment modalities is able to completely eliminate the virus and its recurrence. However, laser phototherapy appears to strongly decrease pain and the interval of recurrences without causing any side effects. Photodynamic therapy can be helpful in reducing viral titer in the vesicle phase, and high-power lasers may be useful to drain vesicles. The main advantages of the laser treatment appear to be the absence of side effects and drug interactions, which are especially helpful for older and immunocompromised patients. Although these results indicate a potential beneficial use for lasers in the management of recurrent herpes labialis, they are based on limited published clinical trials and case reports. The literature still lacks double-blind controlled clinical trials verifying these effects and such trials should be the focus of future research.

High-Frequency Ultrasound as an Option for Scanning of Prepared Teeth: An in Vitro Study

Because of its ability to non-invasively capture hard structures behind soft tissue, high-frequency ultrasound (HFUS)-assisted microscanning could be a patient-friendly and promising alternative for digitization of prepared teeth. However, intra-oral HFUS microscanners for taking digital impressions of prepared teeth are still not available in the clinical setting. Because working range, scanner size, scanning time, surface reconstruction accuracy and costs are major factors in such a system, our overall objective is to minimize hardware efforts and costs while maintaining the accuracy of the surface-reconstructed tooth model in the range 50 μm. In the work described here, we investigated the accuracy of tooth impression taking using a single-element HFUS microscanner with only three translational degrees of freedom under the restriction that only one occlusal scan is performed per tooth. As in favor of time and scanning efforts the data density is expected to be low, the surface reconstruction process is linked to a model-based surface reconstruction approach using a thin spline robust point matching algorithm to fill data gaps. A priori knowledge for the model is generated based on the original HFUS measurement data. Three artificial teeth and one human molar were prepared and scanned using an extra-oral HFUS laboratory microscanner that was built to test and evaluate different scanning setups. A scanner with three translational degrees of freedom was used to scan the teeth from an occlusal direction. After application of the proposed thin-spline robust point matching algorithm-based reconstruction approach, reconstruction accuracy was assessed by comparing the casts with a control group scanned with an extra-oral laser-scanning system. The mean difference between the reconstructed casts and the optical control group was in the range 14-53 μm. The standard deviation was between 21 and 52 μm. This let us assume that the suggested approach can help to decrease hardware efforts while maintaining the robustness of the 3-D surface reconstruction process for future HFUS-based intra-oral scanners.

Accuracy of linear measurements around dental implants by means of cone beam computed tomography with different exposure parameters

OBJECTIVES The aim of this study was to determine the accuracy of linear measurements around dental implants when using CBCT unit devices presenting different exposure parameters. METHODS Dental implants (n = 18) were installed in the maxilla of human dry skulls, and images were obtained using two CBCT devices: G1-Care Stream 9300 (70 kVp, 6.3 mA, voxel size 0.18 mm, field of view 8 × 8 cm; Carestream Health, Rochester, NY) and G2-R100 Veraview® (75 kVp, 7.0 mA, voxel size 0.125 mm, field of view 8 × 8 cm; J Morita, Irvine, CA). Measurements of bone thickness were performed at three points located (A) in the most apical portion of the implant, (B) 5 mm above the apical point and (C) in the implant platform. Afterwards, values were compared with real measurements obtained by an optical microscopy [control group (CG)]. Data were statistically analyzed with the significance level of p ≤ 0.05. RESULTS There was no statistical difference for the mean values of bone thickness on Point A (CG: 4.85 ± 2.25 mm, G1: 4.19 ± 1.68 mm, G2: 4.15 ± 1.75 mm), Point B (CG: 1.50 ± 0.84 mm, G1: 1.61 ± 1.27 mm; G2: 1.68 ± 0.82 mm) and Point C (CG: 1.78 ± 1.33 mm, G1: 1.80 ± 1.09 mm; G2: 1.64 ± 1.11 mm). G1 and G2 differed in bone thickness by approximately 0.76 mm for Point A, 0.36 mm for Point B and 0.08 mm for Point C. A lower intraclass variability was identified for CG (Point A = 0.20 ± 0.25; Point B = 0.15 ± 0.20; Point C = 0.06 ± 0.05 mm) in comparison with G1 (Point A = 0.56 ± 0.52; Point B = 0.48 ± 0.50; Point C = 0.47 ± 0.56 mm) and G2 (Point A = 0.57 ± 0.51; Point B = 0.46 ± 0.46; Point C = 0.36 ± 0.31 mm). CONCLUSIONS CBCT devices showed acceptable accuracy for linear measurements around dental implants, despite the exposure parameters used.

Analysis of tooth preparations for zirconia-based crowns and fixed dental prostheses using stereolithography data sets

STATEMENT OF PROBLEM Under clinical circumstances, it can be challenging for a dentist to achieve an adequate tooth preparation, which is essential for the long-term success of fixed dental restorations. This is particularly true for zirconia restorations fabricated by computer-aided design and computer-aided manufacturing (CAD-CAM) because of the difficulties involved in the scanning and milling process. PURPOSE The purpose of this retrospective study was to use a digital approach to evaluate dental tooth preparations for zirconia-based crowns and fixed dental prostheses (FDP) performed by general dental practitioners in Germany and to find out whether the type of prepared tooth or the type of restoration influenced the outcome. MATERIAL AND METHODS Stereolithography data sets of 182 zirconia frameworks with a total of 305 abutment teeth obtained by the CAD-CAM process were analyzed regarding total occlusal convergence, abutment height, and finish line design using a 3-dimensional (3D) inspection and mesh processing software. The criteria for adequate preparations were defined based on current literature and compared with the measurement results. The Kruskal-Wallis 1-way analysis of variance and the Mann-Whitney U test were applied to detect significant differences (α=.05). RESULTS Only 13 teeth (4.3%) met the clinical requirements for adequate zirconia-based tooth preparations. The mean total occlusal convergence was 17.9 ±9.7 degrees. Molars (23.2 ±10.1 degrees) showed statistically significant difference (P<.001) when compared with premolars (14.2 ±8.2 degrees) and anterior teeth (16.4 ±8.1 degrees). No significant difference was observed between the crown and FDP preparations. The mean abutment height was 5.6 ±1.3 mm. Again, significant differences occurred when tooth types (4.8 ±1.0 mm for molars, 5.2 ±0.9 mm for premolars and 6.9 ±1.2 mm for anterior teeth; P≤.01) were compared. In 92.5% of teeth, the finish line design was not ideal for zirconia-based restorations. CONCLUSION The tooth preparations of general dental practitioners differ from the ideal clinical preparation recommended for zirconia-based restorations. Difficulties are primarily related to the total occlusal convergence and finish line design. Although the outcome is strongly influenced by the type of tooth, the type of restoration seems to have only a minor effect on the tooth preparation quality.

Assessment of the Stress Transmitted to Dental Implants Connected to Screw-Retained Bars Using Different Casting Techniques

Passive fit of the prosthetic superstructure is important to avoid complications; however, evaluation of passive fit is not possible using conventional procedures. Thus, the aim of this study was to check and locate mechanical stress in bar restorations fabricated using two casting techniques. Fifteen patients received four implants in the interforaminal region of the mandible, and a bar was fabricated using either the cast-on abutment or lost-wax casting technique. The fit accuracy was checked according to the Sheffields test criteria. Measurements were recorded on the master model with a gap-free, passive fit using foil strain gauges both before and after tightening the prosthetic screws. Data acquisition and processing was analyzed with computer software and submitted to statistical analysis (ANOVA). The greatest axial distortion was at position 42 with the cast-on abutment technique, with a mean distortion of 450 μm/m. The lowest axial distortion occurred at position 44 with the lost-wax casting technique, with a mean distortion of 100 μm/m. The minimal differences between the means of axial distortion do not indicate any significant differences between the techniques (P = 0.2076). Analysis of the sensor axial distortion in relation to the implant position produced a significant difference (P < 0.0001). Significantly higher measurements were recorded in the axial distortion analysis of the distal sensors of implants at the 34 and 44 regions than on the mesial positions at the 32 and 42 regions (P = 0.0481). The measuring technique recorded axial distortion in the implant-supported superstructures. Distortions were present at both casting techniques, with no significant difference between the sides.

Clinical and Histomorphometric Evaluation of Fresh Frozen Bone Allograft in Sinus Lift Surgery

PURPOSE The aim of this prospective clinical study was to evaluate the clinical and histomorphometric data of newly formed bone tissue from fresh frozen human allograft in sinus lift surgery. PATIENTS AND METHODS Thirty-three sinus lift procedures were performed in 20 patients, divided into two groups. The control group (n = 8) received autogenous bone from the mandibular ramus, and the experimental group (n = 12) received fresh frozen bone (FFB) allograft in chips. After 6 months, 52 implants were placed and 50 biopsies were collected for histomorphometric analysis. Cone beam computed tomography scans were performed at preoperative, immediate postoperative, and delayed postoperative time intervals to assess the degree of graft volume loss. RESULTS There was no statistically significant difference between groups as regards degree of graft volume loss (p = .983), total bone area (p = .191), remaining particles (p = .348), and proportion of active osteoblasts (p = .867). There was a statistically significant difference in the vitality rate between the groups (p = .043). In both groups, all implants were clinically osseointegrated after 4 months. CONCLUSION FFB allograft was shown to be a feasible substitute for autogenous bone graft in sinus lift surgery.