Bacterial inactivation/sterilization by argon plasma treatment on contaminated titanium implant surfaces: in vitro study

Background: Surface treatment by argon plasma is widely used as the last step of the manufacturing process of titanium implant fixtures before their sterilization by gamma rays. The possibility of using such a technology in the daily clinical practice is particularly fascinating. The aim of the present study was to assess the effects of the argon plasma treatment on different titanium implant surfaces previously exposed in vitro to bacterial contamination. Material and Methods: Sterile c.p. titanium implant discs with turned (T, Sa: 0.8μm), sandblasted/acid-etched (SAE, Sa: 1.3μm) and titanium plasma sprayed (TPS, Sa: 3.0μm) surface were used in this study. A strain of Aggregatibacter actinomycetemcomitans ATCC3718 was grown at 37°C under anaerobic conditions for 24 h and then transferred on six discs for each of the three surface types. After 24 hours, a half of the contaminated discs (control group) were directly used to evaluate the colony forming units (CFUs). The other half of the contaminated discs (test group) were treated in an argon plasma chamber for 12 minutes at room temperature prior to be analyzed for CFU counting. All assays were performed using triplicate samples of each material in 3 different experiments. Results: When the CFU counting was carried out on control discs, a total of 1.50x106±1.4x105, 1.55x106±7.07x104 and 3.15x106±2.12x105 CFU was respectively assessed for T, SAE and TPS discs, without statistically significant differences among the three surfaces. On the contrary, any trace of bacterial contamination was assessed for titanium discs treated in the argon plasma chamber prior to be analyzed, irrespectively to the implant surface tested. Conclusions: Within the limit of this study, reported data suggested that the argon plasma technology could be efficiently used to decontaminate/sterilize previously infected titanium implant surfaces

Orthodontic Management of a Mandibular Double-tooth Incisor: A Case Report

The presence of a double-tooth requires specific complex management due to the need for differential diagnosis and following treatment choices. The aim of this report was to present a rare case of a geminated mandibular lateral incisor, treated with an orthodontic approach. A Caucasian 10.9-year-old girl presented a lower right double-tooth incisor, with a class 1 molar and a class 2 cuspid tendency on both sides. The upper arch was constricted as shown by bilaterally tendencies to cross-bite, a slightly lower midline deviation was reported and a lack of space for all four permanent cuspids was confirmed also by the panoramic X-ray. In the lower arch, there was a severe crowding of about 14 mm and a buccally ectopic left canine. Overbite was normal and Overjet minimally increased. The double-tooth was identified like a geminated tooth, for the presence of one root and one pulp canal of increased size, as shown by the radiographic examinations. The anomalous tooth was managed with an orthodontic approach associated with a progressive stripping to reshape the crown. A two-phase treatment plan was performed, based on first maxillary expansion and lip bumper and then fixed appliances, in order to achieve a proper occlusion and a better aesthetic

Clinical Behavior of the Gingival Margin following Conservative "Coronally Dynamic" Restorations in the Presence of Non-Carious Cervical Lesions Associated with Gingival Recession: A Pilot Study

Gingival recessions (GR) are often associated with the presence of non-carious cervical lesions (NCCL). The latter result in the disappearance of the cement-enamel junction (CEJ), with consequent difficulties both in measuring the recession itself and in performing root coverage techniques. The restoration of cervical lesions is consequently an important aspect in the treatment of GR, with the re-establishment of a "new" CEJ. This pilot study aimed to verify whether restorative therapy alone, with the execution of a restoration that mimics the convexity of the natural CEJ and thanks to a slight horizontal over-contour, can stabilize a clot in the intrasulcular site and consequently is able to change the position of the gingival margin in a coronal direction. In periodontally healthy patients, with a non-thin gingival phenotype, 10 GR-associated NCCL restorations were performed using a protocol inspired by concepts of prosthetic conditioning, with a progressively reduced convexity ("coronally dynamic restoration") and de-epithelialization of the gingival sulcus. We observed that 70% of the treated teeth showed a reduction in crown length after 15 days (-0.267 mm), without an increase in probing depth. While considering the limitations of the sample and the need to evaluate the different parameters that can affect the result, the coronally dynamic restoration of NCCL with GR was able to influence the position of the gingival margin in a coronal direction

Gingival Recessions and Periodontal Status after Minimum 2-Year-Retention Post-Non-Extraction Orthodontic Treatment

The objectives of this study were to assess gingival recessions (GR) and periodontal status in patients previously treated with non-extraction orthodontic treatment and retention at a follow-up of a minimum of two years after the end of treatment. Data from patients aged between 16 and 35 years with a previous non-extraction orthodontic treatment and at least 2 years of retention and full records before and after treatment were collected. The casts were digitalized using the 3Shape TRIOS® intraoral scanner and the Viewbox4 software was used for the measurements. The following parameters were scored: inclination of the lower and upper incisors (IMPA and I^SN) and anterior crowding (Little index). The included patients were recalled for a clinical periodontal follow-up examination and the following parameters were evaluated: buccal and lingual GR (mm) of incisors and canines, bleeding of probing score, plaque score, and gingival phenotype. The digital cast analysis showed a mean Little index of 7.78 (SD 5.83) and 1.39 (SD 0.79), respectively, before and after treatment. The initial and final cephalometric analyses showed an I^SN of 103.53° and 105.78° (SD 7.21) and IMPA of 91.3°and 95.1°, respectively. At the follow-up periodontal visits, the patients showed an overall low oral hygiene with bleeding at probing in 66.6% and plaque in the anterior area in 76.2% of patients. From the total examined 240 teeth of the frontal sextants, three patients had GR (from 1 to 6.5 mm): in the upper arch two at canines and one at central incisor, whereas in the lower arch two at central and one at lateral incisors. The gingival phenotype was thick in 55% of cases. The lingual-to-lingual retainers at follow-up were present in 61.9% of patients. A slight increased risk for buccal GR development was found only in correlation with the presence of fixed retainer and thin gingival phenotype mainly in patients with gingivitis. Thus, non-extraction orthodontic treatment performed with controlled forces and biomechanics seems to not affect the development of GR or the periodontal health after retention

Aesthetic Outcomes and Peri-Implant Health of Angled Screw Retained Implant Restorations Compared with Cement Retained Crowns: Medium Term Follow-Up

Single tooth implant restorations in the aesthetic area are a demanding challenge. If a complete osseointegration is mandatory, the final result has to result in a higher standard of biomimetic and soft tissue health among natural teeth. This outcome is traditionally pursued by cementing crowns over individualized abutments. However, in recent years, the need for controlling peri-implant health and the preference towards a retrievable solution has led to an increase in screw-retained crowns, which is not always applicable when the implant axis is not ideal. In the aesthetic area, the use of a novel technical solution represented by the angled screw channel (ASC) of the abutment has been proposed in order to match the advantages of the screwed solution with the aesthetic demands. The aim of this study was to compare ASC crowns to cemented crowns (CC) in single implant restorations using the white esthetic score (WES) and pink esthetic score (PES) at the crown delivery and at a follow-up of a minimum of 2 years. Peri-implant health and marginal bone loss (MBL) were also evaluated. The mean follow-up was 44.3 months, with a mean MBL of 0.22 mm in the ASC group and 0.29 mm in the CC group. The total WES/PES score was 16.6 for ASC, compared with 17.3 for CC at baseline, and 16.2 and 17.1, respectively, at follow-up. Both of the groups reached a high WES/PES, and this was maintained over time, without signs of peri-implant diseases or bone loss, regardless of the choice of connection. In conclusion, ASC can be adopted in cases where the implant axis is not ideal, with aesthetic and functional results that are comparable to implants restored by cemented crowns

The Use of Poly-d,l-lactic Acid (PDLLA) Devices for Bone Augmentation Techniques: A Systematic Review

Poly-d,l-lactic acid (PDLLA) has been proposed in dentistry for regenerative procedures in the form of membranes, screws, and pins. The aim of this review was to evaluate the efficacy of bone augmentation techniques using PDLLA devices. A literature search was carried out by two independent and calibrated reviewers. All interventional and observational studies assessing the efficacy of bone augmentation techniques using PDLLA devices were included. Six studies were included. The relevant variability of design and methods impeded any qualitative or quantitative comparison. Ease of handling, absence of a re-entry phase, moldability of foils, and good soft-tissue response were appreciated characteristics of PDLLA devices. Some drawbacks such as the risk of membrane exposition, a prolonged adsorbability, and a tendency to a fibrous encapsulation of the PDLLA devices have been described, although the clinical significance of these findings is unclear. Clinical data about PDLLA devices for bone regeneration are very scarce and heterogenous. Well-designed randomized controlled trials comparing the use of PDLLA foils and pins with conventional membranes for bone regeneration are strongly encouraged in order to understand the real clinical benefits/drawbacks of this technique

Block Versus Particulate/Titanium Mesh for Ridge Augmentation for Mandibular Lateral Incisor Defects: Clinical and Histologic Analysis

The purpose of this study was to clinically, histologically, and immunohistochemically evaluate the quantity and quality of newly regenerated bone by means of direct clinical measuring and biopsy specimens of alveolar ridges augmented by autogenous cortical bone or titanium micromesh—both filled with autogenous particulate bone graft in the anterior jaws. For the preliminary study, 10 alveolar bone defects in five partially edentulous patients (two men and three women), between 19 and 35 years old (mean: 25.4, SD: 5.94) were selected. Bone defects were randomly (coin toss) divided into two groups: A (micromesh) and B (bone block). The donor site was the mandibular symphysis in all cases. On the return appointment, operative grafts appeared well incorporated into the native bone, which suggests that good contact and fit between the graft and the recipient site had been obtained during the first surgery. Histologic investigations confirmed excellent integration and revascularization of the graft in both study groups, with formation of new bone tissue without any relevant inflammation.The purpose of this study was to clinically, histologically, and immunohistochemically evaluate the quantity and quality of newly regenerated bone by means of direct clinical measuring and biopsy specimens of alveolar ridges augmented by autogenous cortical bone or titanium micromesh-both filled with autogenous particulate bone graft in the anterior jaws. For the preliminary study, 10 alveolar bone defects in five partially edentulous patients (two men and three women), between 19 and 35 years old (mean: 25.4, SD: 5.94) were selected. Bone defects were randomly (coin toss) divided into two groups: A (micromesh) and B (bone block). The donor site was the mandibular symphysis in all cases. On the return appointment, operative grafts appeared well incorporated into the native bone, which suggests that good contact and fit between the graft and the recipient site had been obtained during the first surgery. Histologic investigations confirmed excellent integration and revascularization of the graft in both study groups, with formation of new bone tissue without any relevant inflammation