Cold plasma: a novel approach to treat infected dentin—a combined ex vivo and in vitro study

Objectives

The aim of this study was to evaluate the antimicrobial effect of cold plasma (CP) on infected dentin surfaces in vitro and ex vivo.

Materials and methods

To examine the effect of cold plasma on root surfaces, 24 root surfaces were infected with Streptococcus mitis. Specimens were randomly divided into three groups: Within the control group (C), root surfaces were rinsed with NaCl; root surfaces in the second group were additionally scaled and root planed (SRP), and in the third group, root surfaces were rinsed, scaled, root planed, and in addition, CP was applied (SRP + CP). To examine the effect of CP on root caries lesions (RCLs), 16 freshly extracted teeth with symmetrical carious lesions were equally divided into two groups. In the control group, carious lesions were treated with chlorhexidine (CHX), whereas CHX was applied in conjunction with CP in the test group (CHX + CP). For microbiological analysis, dentin samples were serially diluted and CFU counts were estimated after 24 h of incubation.

Results

Compared to C, mean CFU values for SRP and SRP + CP were significantly lower (p < 0.05). In addition, mean CFUs for SRP + CP were reduced to 0 and, therefore, significantly lower than SRP (2.98 log CFU/mL) alone (p = 0.000, Mann-Whitney U). Regarding RCLs, significantly lower mean CFU values were observed for CHX + CP when compared to CHX (4.45 vs. 2.67 log CFU/mL, p = 0.002, Mann-Whitney U test).

Conclusions

For disinfection of exposed root surfaces, the adjunctive application of CP is promising. In addition, the combined application of CHX + CP has the potential to disinfect root dentin surfaces.

Clinical relevance

It was shown that the combination of cold plasma with CHX is the best available option for the disinfection of root surfaces.

     

Clinical performance of a light-cured denture base material compared to polymethylmethacrylate—a randomized clinical study

The aim of this study was to evaluate the clinical long-term performance of a visible light-cured resin (VLCR) denture base material and to compare it to a well-established polymethylmethacrylate (PMMA)-based denture acrylic in a randomized split-mouth clinical long-term study. One hundred removable partial dentures in 90 patients, with at least two saddles each, were investigated. One saddle was made of VLCR, while the other was made of PMMA at random. Plaque adhesion, tissue reaction, and technical parameters of the dentures were assessed 6, 12, and 18 months after treatment. Statistical analysis was performed using the Wilcoxon rank-sum test. Though VLCR showed higher plaque adhesion than PMMA after 6, 12, and 18 months (p < 0.001), there were no important differences with regard to tissue reaction. Concerning plaque adhesion, surface quality with regard to the lower side, interfaces between denture acrylic and metal and the boundary between denture acrylic and denture tooth PMMA was rated higher than VLCR. The surface quality of the upper side of the denture saddles showed no significant differences (p > 0.05). Neither VLCR nor PMMA showed discoloration at any point in time (p > 0.05). It can be concluded that VLCR is a viable alternative for the production of removable dentures. Especially in patients with hypersensitivities to PMMA, VLCR is particularly suitable for clinical use.     

Posttreatment stability of an anterior open-bite by molar intrusion compared with 2-jaw surgery — a retrospective study

Clinical Oral Investigations - This study aimed to compare post-treatment stability in patients with anterior open-bite (AOB) between those treated surgically (orthognathic 2-jaw surgery) and...     

Does irradiation of the tooth structure interfere with oxygen saturation measured by pulse oximetry?—An ex vivo laboratorial study

The effect of tooth structure subjected to ionising radiation on oxygen saturation levels (SpO₂) measured by pulse oximetry was investigated. Fifty-four extracted human third molars were sectioned mesiodistally. Pulse oximeter diodes were placed in prefabricated silicone moulds, secured on a vise with tooth surfaces placed between the diodes and the participant's finger, and SpO₂ levels were measured. After that, the tooth surfaces were subjected to ionising radiation in fractionated doses of up to 70 Gy, and SpO₂ was measured according to the protocol described. The Kolmogorov–Smirnov test was used for the analysis of normality of the quantitative variables, and Student's t-test compared mean SpO₂ levels before and after irradiation. Mean SpO₂ after irradiation was 94.6 ± 0.9%, without a statistically significant difference from SpO₂ before irradiation, which was 94.7 ± 0.6%. Irradiation of the tooth structure did not interfere with SpO₂ levels measured by pulse oximetry.     

Clinical evaluation of the performance and safety of a new dentine substitute, Biodentine, in the restoration of posterior teeth — a prospective study

Objectives

A multicentric randomized, 3-year prospective study was conducted to determine for how long Biodentine, a new biocompatible dentine substitute, can remain as a posterior restoration.

Materials and methods

First, Biodentine was compared to the composite Z100®, to evaluate whether and for how long it could be used as a posterior restoration according to selected United States Public Health Service (USPHS)’ criteria (mean ± SD). Second, when abrasion occurred, Biodentine was evaluated as a dentine substitute combined with Z100®.

Results

A total of 397 cases were included. This interim analysis was conducted on 212 cases that were seen for the 1-year recall. On the day of restoration placement, both materials obtained good scores for material handling, anatomic form (0.12?±?0.33), marginal adaptation (0.01?±?0.10) and interproximal contact (0.11?±?0.39). During the follow-up, both materials scored well in surface roughness (≤1) without secondary decay and post-operative pain. Biodentine kept acceptable surface properties regarding anatomic form score (≤1), marginal adaptation score (≤2) and interproximal contact score (≤1) for up to 6 months after placement. Resistance to marginal discoloration was superior with Biodentine compared to Z100®. When Biodentine was retained as a dentine substitute after pulp vitality control, it was covered systematically with the composite Z100®. This procedure yielded restorations that were clinically sound and symptom free.

Conclusions

Biodentine is able to restore posterior teeth for up to 6 months. When subsequently covered with Z100®, it is a convenient, efficient and well tolerated dentine substitute.

Clinical relevance

Biodentine as a dentine substitute can be used under a composite for posterior restorations.     

The impact of the new scene drug “crystal meth” on oral health: a case–control study

Objective

The use of methamphetamine (MA), a highly addictive stimulant, is rapidly increasing, with MA being widely abused as the scene drug “Crystal Meth” (CM). CM has been associated with severe oral health effects, resulting in so-called “Meth mouth”. This term appeared for the first time in 2005 in the literature and describes the final complex of symptoms including rampant caries, periodontal diseases and excessive tooth wear. The aim of this study was to investigate the effects of chronic CM abuse on teeth and intraoral tissue with respect to potential symptoms of Meth mouth.

Materials and methods

In cooperation with two centres for addiction medicine, we performed clinical intraoral investigations in 100 chronic CM users and 100 matched-pair controls. We undertook a caries and periodontal examination by using the clinical parameters DMF-T/DMF-S, bleeding on probing index (BOP) and periodontal screening index (PSI) and tested individual oral hygiene by using approximal space plaque index (API). All clinical data were analysed by the t test for independent samples.

Results

We found significantly larger numbers of caries (p < 0.001) and higher levels of gingival bleeding (p < 0.001) and periodontal disease (p < 0.001) among CM users. Oral hygiene was significantly lower in CM users (p < 0.024).

Conclusion

Chronic CM use can lead to extensive potential damage within the intraoral cavity. When CM is used over a long period of time and in the absence of treatment, clinical symptoms in terms of Meth mouth syndrome cannot be excluded.

Clinical relevance

Based on our results, we recommend a specific prevention and therapeutic concept including educational campaigns for MA users and specialized dental care for CM patients.

     

Follow-up study to investigate symmetry and stability of cranioplasty in craniosynostosis – Introduction of new pathology-specific parameters and a comparison to the norm population

PurposeCranioplasty and modulation of frontoorbital advancement (FOA) in children with craniosynostosis aims to achieve an attractive aesthetic and functional rehabilitation of the forehead area, comparable to that in unaffected children. Based on a three-dimensional surface scan, a cephalometric data evaluation with new parameters for the quantification of physiological and pathological cranial morphologies, and objective evaluation of postoperative follow-up in comparison to an age-equivalent standard population, were performed.Materials and methodsIn a prospective study, 80 children were operated on with non-syndromic craniosynostosis (trigonocephalus, n = 30; plagiocephalus, n = 10; scaphocephalus, n = 38; brachycephalus, n = 2) and pre- and 3, 6, 12, 18 and 30 months postoperative three-dimensional surface scans were obtained (3DShape, Erlangen, Germany) and morphometrically measured (Onyx Ceph, Image Instruments, Chemnitz, Germany). In addition, 49 healthy children who were not operated on were measured at equivalent ages (n = 25 [6 months]; n = 20 [9 months]; n = 4 [12 months]).ResultsAll patient groups showed stable long-term results with regard to shaping of the forehead. Cranioplasty in patients with scaphocephalus resulted in a significant widening of the anterior (73.9 ± 3.5 mm; p < 0.001) and posterior (132.2 ± 5.2 mm; p < 0.001) cranial width, with no significant difference from the norm population 1 year after surgery (p = 0.6597). As parameters for the correction of trigonocephaly, the frontal angle showed significant improvement (145.9 ± 3.7°; p < 0.001). While the parietal angle 12 months after surgery showed similar values as the norm population, the frontal angle was about 10° smaller than in healthy children (p = 0.0055), despite a clinically inconspicuous physiognomy. As part of the correction of plagiocephaly, the patients tended to relapse in the postoperative course, although there was no statistically significant difference in the frontal angle compared to that in the norm population (153.3 ± 3.9°; p = 0.06). While 6 months after surgery all patients showed a normal cranial volume development compared to healthy children of the same age, the volumes of brachycephalic patients remained below the norm (1244.2 ± 153.2 cm³; p = 0.0244). Overall, the analysis of the norm population showed a growing dispersion of measurement values with increasing age, which was observed to be more concentrated in the operated cranial morphologies.ConclusionThe determination of new pathology-specific morphometric parameters on the three-dimensional surface scan enables an objective quantification of physiological and pathological cranial morphologies of children. A comparison of operated children with a healthy, age-appropriate comparison group showed that preoperative and statistically significant deviations of the new measuring parameters in long-term follow-up could be normalized through surgical intervention, although this does not apply without limitations to children with coronary suture synostosis.     

Current and future strategies for the control of mature oral biofilms—Shift from a bacteria-targeting to a matrix-targeting approach

Oral biofilms, unlike those formed at most other sites in the human body, are unique because surgical intervention is usually unnecessary for their removal. The control of oral biofilms relies mainly on mechanical elimination. Chemical controls are used as alternative or adjunctive methods when elimination using dental instruments proves difficult. For many years, researches have focused on how microorganisms could be rapidly killed using high concentrations of antimicrobials or new antibacterial agents.New strategies that target the matrices of mature biofilms are needed because biofilm matrices inhibit the effect of antimicrobial agents through absorption and degradation. These strategies include the following possibilities: (1) use of antimicrobial agents with superior penetration properties and (2) degradation or detachment of matrix polymers.In order to investigate the penetration properties of antimicrobial agents, time-lapse microscopy can be used for noninvasive visualization of antimicrobial action inside models of oral biofilms. Factors that affect drug penetration properties include molecular weight, charge, hydrophilic–hydrophobic balance, and malabsorption/modification by the biofilm matrix.However, strategies that rely on antimicrobial agents have an important limitation. Even if the microorganisms are eradicated, their biofilm structure remains intact and may promote secondary biofilm and tartar formation. Therefore, future strategies should shift their focus to degradation and/or removal of matrix polymers.Some detachment-promoting agents have been reported. These agents have the potential to control biofilm accumulation effectively. Since the clinical efficacy remains unclear, and in addition to limitations of targeting a specific polysaccharide component and retention properties, further investigations are warranted.     

Correction to: Accuracy of full‑arch digitalization for partially edentulous jaws — a laboratory study on basis of coordinate‑based data analysis

Clinical Oral Investigations -     

The impact of harvest length and detachment of the interosseous membrane on donor-site morbidity following free fibula flap surgery—a biomechanical experimental study

Purpose

The fibula flap has been established for orofacial reconstruction following ablative surgery. Donor-site morbidity of the lower leg may be explained by the harvest technique and particularly by detachment of the M. extensor halluces longus (EHL) and M. extensor digitorum longus (EDL).

Two-stage distalization of the mental foramen to manage posterior mandibular vertical bone deficiency—a prospective observational study

Inferior alveolar nerve (IAN) transpositioning is a modality utilized to manage posterior mandibular vertical deficiency. Several complications have been reported including improper implant positioning, mandibular body fracture, and neurosensory disturbance. The aim of this prospective observational study was to introduce a two-stage mental foramen distalization technique to minimize the complications associated with IAN transpositioning. Ten patients with severely atrophied mandibular ridges were included. Cone beam computed tomography was ordered to accurately locate the position of the IAN and its incisive terminal branch before designing the outline of two cortical osteotomies anterior and posterior to the mental foramen. The osteotomies were created using a piezoelectric device, followed by separation and identification of the nerve. The incisive branch was severed to freely transpose the IAN. A new foramen was created far distally and the cortical windows were repositioned and fixed with two screws. Healing was uneventful for all patients. Neurosensory recovery was assessed by MRC scale. All cases showed full recovery within 6 weeks, except for two patients who showed complete recovery after 16 weeks. Four months postoperative, all patients showed complete consolidation of the cortical windows without any signs of failure implants were placed at the pre-planned surgical sites. Histomorphometric analysis of core biopsies from seven surgical sites showed bone area percentages ranging from 46% to 63%. The two-stage mental foramen distalization technique is a predictable and safer technique for IAN transpositioning specifically in cases of vertical bone deficiency associated with limited inter-arch space.     

Clinical and microbiological effects of an essential-oil-containing mouth rinse applied in the “one-stage full-mouth disinfection” protocol—a randomized doubled-blinded preliminary study

The aim of this randomized double-blinded preliminary study was to evaluate the clinical and microbiological long-term effects of an essential-oil-containing mouth rinse as the active agent utilized in the "one-stage full-mouth disinfection protocol." Probing pocket depth and plaque and gingival indices were evaluated by the same calibrated examiner in all teeth of 20 moderate chronic periodontitis subjects. Presence of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Tannerella forsythensis were determined by polymerase chain reaction in nonstimulated saliva, tongue dorsum, and pooled subgingival samples. The subjects were randomized into two groups: full-mouth disinfection plus essential oils (Listerine) or full-mouth disinfection plus placebo. Clinical and microbial parameters were evaluated at baseline (T0), 45 (T1) and 180 (T2) days after therapy and analyzed using analysis of variance, Student t, and Wilcoxon tests (p < 0.05). No significant differences were observed between groups regarding clinical measurements at baseline. However, in the later examinations, T1 and T2, the test group always presented higher reductions of pocket depth, plaque index, and gingival index compared to the control group. The essential-oils group revealed significant reduction on occurrence of P. gingivalis in saliva comparing baseline and 45 days; this difference still remain at 180 days. The essential-oil-containing mouth rinse demonstrated beneficial effects on clinical parameters. Microbiological findings were less consistent. The results of this preliminary study suggest further investigations.