A simplified digital workflow for the prosthetic finishing of implant rehabilitations: a case report

Efficacy Ozone Therapy in Reducing Periodontal Disease

The aim of this study is to highlight the properties of ozone as an aid to non-surgical therapy compared to non-surgical therapy alone. This study included thirty Caucasian patients (eighteen women and twelve men) aged between 35 and 65, recruited at the Oral Hygiene and Prevention Center of the Dental Clinic of the Vita-Salute San Raffaele University, at the San Raffaele hospital in Milan. The periodontal probing was recorded with a PC-PUNC 15 manual probe (Hu Friedy) at time 0; the scaling and root planing session was performed at T1 with or without the aid of ozone therapy, and then, the patients were re-evaluated at one month (T2), three months (T3), and six months (T4). The results obtained show that there are not statistically significant differences in terms of reduction in clinical periodontal indices such as plaque, bleeding, and pocket depth between the two groups. Therefore, treatment with ozoral gel would not seem to improve non-surgical periodontal therapy alone. However, clinical periodontal indices significantly improved in patients treated with non-surgical therapy and ozone gel. From this point of view, ozone gel can be used as an aid to non-surgical therapy due to its excellent characteristics, in particular, its powerful virucidal action.

Aesthetic Restorations: The Role of The Dental Hygienist in Professional Maintenance: In Vitro Microbiological Study

The aim of this in vitro study is to try to identify a treatment in the field of professional oral hygiene techniques that is ideal and less invasive with regard to prosthetic restorations, chosen in lithium disilicate and feldspar ceramics. Seventeen veneers were prepared (eight in lithium disilicate and nine in feldspar ceramic) and each of them was attached to an extracted tooth. The treatment groups were initially contaminated in the Microbiology Laboratory of Università Vita-Salute San Raffaele. After 24 h they were treated with four different methods of professional oral hygiene and were then sent to the Microscopy Laboratory, in which they were analysed by SEM, with 180X, 250X, and 500X magnification, to assess any damage caused to the treated surfaces. The SEM analysis produced 64 images that were evaluated by an experienced dentist, and the use of the prophetic cup seemed to be the most suitable among the evaluated treatments. However, from a microbiological point of view, this method was the least effective in terms of reducing bacterial growth. In this regard, the use of a prophylactic rubber cup combined with a 0.20% chlorhexidine gel is recommended during professional oral hygiene sessions for the maintenance of aesthetic prosthetic restorations.

Effect of Short-Term Ageing Treatment on Bending Force Behavior of Commercial Nickel-Titanium Archwire

Superelastic nickel-titanium (NiTi) archwires have become the preferred archwire for orthodontic alignment and the levelling stage due to their ability to exert a light force on teeth throughout a wide range of tooth movement. The magnitude and trend of the force exerted on the malposed tooth is influenced by the orthodontist's consideration of the size and geometry of the NiTi archwire during orthodontic therapy. In this work, a novel approach of a short-term ageing treatment was utilized to modify the magnitude and trend of the bending force of a commercial superelastic NiTi archwire. The bending behavior of the superelastic NiTi archwire was altered by subjecting it to different temperatures in an ageing treatment for 15 min. The bending behavior of the aged NiTi archwire was examined using a three-point and three-bracket setup. The commercial NiTi archwire's bending forces in both the three-point and three-bracket configurations were successfully altered by the 15 min ageing treatment. During unloading in the three-bracket arrangement, the NiTi archwires aged at 490 °C or 520 °C exhibited a lower magnitude and more consistent force compared to the NiTi archwires aged at 400 °C or 430 °C. Ageing the archwire for 15 min at 490 °C produced a suitable size of Ni₄Ti₃ precipitate, which makes the wire more flexible during bending and reduces the unloading force in the three-bracket bending configuration. The short-term aged NiTi archwire could be used to enhance the force delivery trend to the malposed tooth by lowering the amplitude of the force delivered and sustaining that force throughout the orthodontic treatment duration.

Impact of Dentistry Materials on Chemical Remineralisation/Infiltration versus Salivary Remineralisation of Enamel-In Vitro Study

The aim of this study is to evaluate salivary remineralisation versus chemical remineralisation/infiltration of enamel, using different dentistry materials. The enamel changes were studied using confocal laser scanning microscopy (CLSM), and the depth of lesions and demineralisation/remineralisation/infiltration percentage were calculated. Additionally, the macro elemental composition of the teeth was performed using atomic absorption spectroscopy (AAS). Two studies were performed: (i) demineralisation of enamel in 3% citric acid and infiltration treatment with infiltration resin (Icon, DMG), remineralisation with Fluor Protector (Ivoclar Vivadent) and artificial saliva pH 8; and (ii) enamel demineralisation in saliva at pH 3 and remineralisation at salivary pH 8. The results showed that, firstly, for the remineralisation of demineralised enamel samples, Fluor Protector (Ivoclar Vivadent) was very effective for medium demineralised lesions followed by saliva remineralisation. In cases of deep demineralisation lesions where fluoride could not penetrate, low viscosity resin (Icon, DMG, Hamburg) effectively infiltrated to stop the demineralisation process. Secondly, remineralisation in salivary conditions needed supplementary study over a longer period, to analyse the habits, diet and nutrition of patients in detail. Finally, demineralisation/remineralisation processes were found to influence the macro elemental composition of enamel demineralisation, with natural saliva proving to be less aggressive in terms of decreasing Ca and Mg content.

Dental Pain in Care Homes: Is It a Phenomenon? A Systematic Review of the Literature

Background: Evidence suggests that 80% of residents living in nursing homes have moderate to severe pain, could dental causes be an under reported contributory factor. The evidence suggests that this is an under-researched area. Our project aims were to explore and consolidate the current literature and conduct some stakeholder groups with care home managers and dentists. Our stakeholder group will be reported elsewhere. Methods: We used the SPIDER framework to set out key search terms. Which included “dementia” OR “cognitively-impaired” OR “carehome residents” AND “dental pain” OR “oralfacial pain” OR “mouth pain” AND “pain assessment” OR “pain identification”. A literature search was carried out on 8 and 9 March 2022 in the electronic databases: Cochrane, PubMed, Medline, Dental & Oral Sciences Source, CINAHL, Global Health, SocINDEX, Ovid (Medline) and Scopus. Restrictions were placed on dates and language (2012–2022 and English only). Results: The search yielded 775 papers up to the year 2020. After screening and exclusion, we were left with five papers: four quantitative and one qualitative. Conclusions: This review demonstrates that there has been very little research into oral health and/or dental pain in adults with dementia. Furthermore, the recommendations have yet to be taken forward. Identifying pain in older adults with dementia remains challenging. There is a need to develop an algorithm in conjunction with care home staff and dental practitioners in order to identify and address the pain associated with dental disease in adults with dementia.

How Does Orthodontic Mini-Implant Thread Minidesign Influence the Stability?—Systematic Review with Meta-Analysis

Background: Clinical guidelines are lacking for the use of orthodontic mini-implants (OMIs) in terms of scientific evidence referring to the choice of proper mini-design. Thus, the present study aimed to investigate to what extent orthodontic mini-implant thread design influences its stability. Methods: Search was conducted in five search engines on 10 May. Quality assessment was performed using study type specific scales. Whenever possible, meta-analysis was performed. Results: The search strategy identified 118 potential articles. Twenty papers were subjected to qualitative analysis and data from 8 papers—to meta-analysis. Studies included were characterized by high or medium quality. Four studies were considered as low quality. No clinical studies considering the number of threads, threads depth, or TSF have been found in the literature. Conclusions: Minidesign of OMIs seems to influence their stability in the bone. Thread pitch seems to be of special importance for OMIs retention—the more dense thread—the better stability. Thread depth seems to be of low importance for OMIs stability. There is no clear scientific evidence for optimal thread shape factor. Studies present in the literature vary greatly in study design and results reporting. Research received no external funding. Study protocol number in PROSPERO database: CRD42022340970.

Mechanical Characterization of Dental Prostheses Manufactured with PMMA-Graphene Composites

The use of a PMMA composite with graphene is being commercialized for application as dental prostheses. The different proportions of fibers provide a wide range of colors that favors dental esthetics in prostheses. However, there are no studies that have explained the influence that graphene has on the mechanical properties. In this contribution, we studied the PMMA and PMMA material with graphene fibers (PMMA-G) in the form of discs as supplied for machining. The presence of graphene fibers has been studied by Raman spectroscopy and the Shore hardness and Vickers micro hardness were determined. Mechanical compression tests were carried out to obtain the values of maximum strength and Young’s modulus (E) and by means of pin-on-disc wear tests, the specific wear rate and the friction coefficients were determined following the established international standards. Finally, the samples were characterized by field emission scanning electron microscopy (FESEM) to characterize the graphene’s morphology inside the PMMA. The results showed the presence of graphene in PMMA and was estimated in an amount of 0.1027% by weight in G-PMMA. The Shore hardness and Vickers microhardness values did not show statistically significant differences. Differences were observed in the compression maximum strength (129.43 MPa for PMMA and 140.23 for PMMA-G) and E values (2.01 for PMMA and 2.89 GPa for PMMA-G) as well as in the lower wear rate for the G-PMMA samples (1.93 × 10−7 for PMMA and 1.33 × 10−7 mm3/N·m) with a p < 0.005. The coefficients of friction for PMMA-G decreased from 0.4032 for PMMA to 0.4001 for PMMA-G. From the results obtained, a slight content in graphene produced a significant improvement in the mechanical properties that could be observed in the prosthesis material. Therefore, we can state that the main attraction of this material for dental prosthesis is its esthetics.

A New Approach to Diagnosis to Posterior Cross Bite: Intraoral Photography and Wala Ridge

A posterior crossbite is an occlusion disorder that occurs in the transverse plane. It occurs when the buccal cusps of the upper premolars and molars engage lingually with the buccal cusps of the lower teeth. It can be unilateral or bilateral (involving one or more teeth) in the primary, mixed, or permanent dentition. A crossbite may appear in early dentition stages and it can be dental or functional. It can lead to skeletal crossbite in mixed dentition. Therefore, early diagnosis and treatment are crucial. Material and methods: The selected sample included 204 patients in growing stage divided into two groups: a study group of 102 patients with posterior crossbite and a control group of 102 patients without malocclusion. To analyze the pathology, intraoral frontal photographs and study models were taken, in which the bone component was measured from the Wala Ridge. Results: The use of the photographs to study the Wala Ridge was confirmed. The mean maxillary width was 57.8 mm (SD 1.7) and mandibular width was 56.4 mm (SD 1.7) for the control group, with a maxillomandibular difference of 1.4 mm (SD 0.7); and 52.7 mm (SD 3.7) and 55.5 mm (SD 3.6), respectively, with a maxillomandibular difference of −2.8 mm (SD 1.4) for the study group. A higher maxillomandibular discrepancy was observed in patients with a posterior crossbite that involved more than one tooth in addition to the permanent first molar. It was also higher in patients with bilateral posterior crossbite. Conclusions: Intraoral frontal photography can be used as a diagnostic method to measure the maxillomandibular difference using the Wala Ridge.

Accuracy of full-arch digitalization for partially edentulous jaws - a laboratory study on basis of coordinate-based data analysis

Objectives

To compare the accuracy (trueness and precision) of direct digitization of four different dental gap situation with two IOS (intraoral scanner).

Materials and methods

Four partially edentulous polyurethane mandible models were used: (1) A (46, 45, 44 missing), (2) B (45, 44, 34, 35 missing), (3) C (42, 41, 31, 32 missing), and (4) D (full dentition). On each model, the same reference object was fixed between the second molars of both quadrants. A dataset (REF) of the reference object was generated by a coordinate measuring machine. Each model situation was scanned by (1) OMN (Cerec AC Omnicam) and (2) PRI (Cerec Primescan AC) (n = 30). Datasets of all 8 test groups (N = 240) were analyzed using inspection software to determine the linear aberrations in the X-, Y-, Z-axes and angular deviations. Mann–Whitney U and two-sample Kolmogorov–Smirnov tests were used to detect differences for trueness and precision.

Results

PRI revealed higher trueness and precision in most of the measured parameters (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\overrightarrow{V}}_{E}$$\end{document}V→E 120.95 to 175.01 μm, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\overrightarrow{V}_{E}$$\end{document}V→E(x) − 58.50 to − 9.40 μm, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\overrightarrow{V}_{E}$$\end{document}V→E (z) − 70.35 to 63.50 μm), while OMN showed higher trueness for \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\overrightarrow{V}_{E}$$\end{document}V→E (y) regardless of model situation (− 104.90 to 34.55 μm). Model D revealed the highest trueness and precision in most of the measured parameters regardless of IOS (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\overrightarrow{V}_{E}$$\end{document}V→E 120.95 to 195.74 μm, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\overrightarrow{V}_{E}$$\end{document}V→E (x) − 9.40 to 66.75 μm,\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\overrightarrow{V}_{E}$$\end{document}V→E (y) − 14.55 to 51.50 μm, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\overrightarrow{V}_{E}$$\end{document}V→E (z) 63.50 to 120.75 μm).

Conclusions

PRI demonstrated higher accuracy in the X- and Z-axes, while OMN depicted higher trueness in the Y-axis. For PRI, Model A revealed the highest distortion, while for OMN, Model B produced the largest aberrations in most parameters.

Clinical relevance

Current results suggest that both investigated IOS are sufficiently accurate for the manufacturing of tooth-borne restorations and orthodontic appliances. However, both hardware specifications of IOS and the presence of edentulous gaps in the dental model have an influence on the accuracy of the virtual model dataset.

Immediate restoration of fixed full-arch prostheses placed on implants in both fresh and healed sockets using the flat one-bridge technique: a 7-year retrospective study

Background

The aim of this retrospective study was to document the long-term clinical efficacy of a surgical-prosthetic technique (the flat one-bridge technique) involving the immediate restoration of both postextraction and nonpostextraction implants supporting full-arch restorations.

Methods

Implants were placed by adapting the axis to the available bone. Flat definitive abutments were connected during surgery and never disconnected to compensate for eventual implant disparallelism. Bone grafting was performed when needed. The patients received a screw-retained provisional restoration within 48 h of surgery and a final screw-retained prosthesis within 1 year.

Results

Sixty-six patients received 494 implants distributed in 75 prostheses. The median follow-up was 86 months (range 82–168 months). Only three implants had failed at the last follow-up. Implant survival was 99.6%.

Conclusion

The flat one-bridge prosthetic protocol is a viable procedure with excellent long-term outcomes. No difference in clinical success could be observed between postextractive and nonpostextractive implants.

New and Recovered Temporary Anchorage Devices, In Vitro Assessment of Structural and Surface Properties

The orthodontic miniscrew (TADs) is a device that is fixed into bone in the short term for the purpose of enhancing orthodontic anchorage. The aim of our study was to investigate the structural and surface properties of recovered TADs after orthodontic treatment, and compare them to new TADs. TADs (n = 15) from the same manufacturer (Absoanchor; Dentos, Daegu, Korea) were assessed; n = 10 were recovered from patients after orthodontic treatment and n = 5 were new. We performed electrochemical investigations, scanning electron microscopy (SEM) and microbiological analysis. Qualitative analysis on general electrochemical polarization revealed that the TADs retrieved from the patients provided much lower current densities in the passivity zone, and the oxidative processes taking place on their surface were of lower intensity. The surface morphologies of the tips of the retrieved mini-implants showed less sharp tips and smooth surfaces. Defects in the form of pores or cracks could be identified in both evaluated TAD groups. All retrieved TADs showed signs of biological materials (SEM analysis) and contamination on their surfaces. In conclusion, these results can assist orthodontists in comprehending the complexities of TAD behavior with respect to their design and structure.