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OBJECTIVES Our aim is to study titanium remains in a bone model during standardized implantoplasty under different isolation and protective modalities. MATERIAL AND METHODS Forty implants were placed in artificial spongy bone blocks mimicking a horizontal bone loss and implant neck protrusion of 5 mm. Samples were randomly divided into four groups (n = 10), which were treated as follows: rubber dam (A), a dental adhesive paste (B), bone wax (C), and an unprotected positive control (D). Implantoplasty was performed using carbide and diamond burs under strict water cooling and standardized suction. After removal of the respective isolation materials, the bone blocks were thoroughly rinsed with tap water for 3 min and titanium chips were collected using a filter integrated in the model. The filter paper was removed and dissolved in 37% hydrochloric acid for 2 h at 120 °C and the titanium remnants were quantified using atomic absorption spectrometry. RESULTS None of the test groups were able to completely prevent titanium particle contamination. Rubber dam (691 ± 249 µg) and bone wax (516 ± 157 µg) were found to be significantly more protective than the positive control (2313 ± 747 µg) (p < 0.001) with respect to the amount of titanium particles that remained in the bone model after implantoplasty. The adhesive paste group (1863.5 ± 538 µg) was not significantly different from the positive control (p = 0.19). CONCLUSIONS Despite some limitations of the present study, titanium particles resulting from a standardized implantoplasty can be assumed to be significantly reduced when the tissues/bone were protected with rubber dam and bone wax, or a combination, depending on individual accessibility. CLINICAL RELEVANCE Tissue protective measures to reduce or avoid particle contamination during implantoplasty is possible and should be considered and further clinically assessed to avoid iatrogenic inflammatory reactions.

PURPOSE To provide a systematic overview of preclinical research regarding bone defect formation around different implant surfaces after ligature-induced peri-implantitis models in dogs. Two focused questions were formulated: 'How much bone loss can be expected after a certain time of ligature induced peri-implantitis?' and 'Do different implant types, dog breeds and study protocols differ in their extent of bone loss?' MATERIALS AND METHODS A systematic literature search was conducted on four databases (MEDLINE, Web of Science, EMBASE and Scopus). Observations, which consisted of bone defects measured directly after ligature removal in canine models, were included and analysed. Two approaches were used to analyse the relatively heterogeneous studies that fulfilled the inclusion criteria. First, separate simple linear regressions were calculated for each study and implant surface, for which observations were available across multiple time points. Second, a linear mixed model was specified for the observations at 12 weeks after ligature initiation, and assessing the potential influencing factors on defect depth was explored using lasso regularisation. RESULTS Thirty-six studies with a total of 1082 implants were included after. Bone loss was determined at different time points, either with clinical measurements radiographically or histologically. Different implant groups [e.g. turned, sand-blasted-acid-etched (SLA), titanium-plasma-sprayed (TPS) and other rough surfaces] were assessed and described in the studies. A mean incremental defect depth increase of 0.08 mm (SD: -0.01-0.28 mm) per week was observed. After 12 weeks, the defect depths ranged between 0.7 and 5 mm. Based on the current data set, implant surface could not be statistically identified as an essential factor in defect depth after 12 weeks of ligature-induced peri-implantitis. CONCLUSION Expectable defect depth after a specific time of ligature-induced peri-implantitis can vary robustly. It is current

BACKGROUND The Bologna reform resulted in a drastic restructuring of pre-clinical training courses at the University of Zurich. The aim of this study was to assess student pre-clinical scaling/root planning skills after just 8.5 hours of manual training. MATERIAL AND METHODS Three consecutive classes of dental students (n = 41; n = 34; n = 48) were tasked with removing lacquer concrement from the maxillary left canine on a typodont using Gracey and universal (Deppeler M23A) curettes. At baseline (prior to instruction), a timed five-minute session of scaling/root planning was undertaken. The second scaling/root planning session was held immediately following training. Eight experienced dental hygienists and eight lay people served as positive and negative controls, using the same instruments and time limit, respectively. Instrumented teeth were collected, scanned and planimetrically analysed for the percentage of tooth surface cleaned. Statistical analyses were performed to assess the dental students' improvement after the training (Wilcoxon signed-rank test) and to compare it to that of laypeople and dental hygienists (Kruskal-Wallis rank sum test followed by Conover's post hoc test). RESULTS At baseline, the dental students' mean scaling scores of the cleaned surfaces were not significantly different than those of laypeople (29.8%, 31.0%, 42% vs 27.9%). However, after 8.5 hours of manual training, the students' ability to clean the maxillary tooth improved significantly and they achieved mean removal values of 61.7%, 79.5% and 76% compared to the 67.4% (P < .001) of the experienced dental hygienists (Tables Tables and ). There were no statistically significant differences between the scores achieved by students after training and those achieved by experienced dental hygienists. CONCLUSION A shortened pre-clinical training time was sufficient for students to acquire the basic scaling/root planning skills needed in preparation for clinical training. Further research

BACKGROUND: For periodontal treatment, the full mouth disinfection approach suggests disinfection of oral soft tissues, such as tongue and tonsils concomitant to scaling and root planning since patients might benefit from treatment of these oral niches either. Periodontopathogenes in tonsillar tissue support this hypothesis. This prospective controlled clinical study investigated the change in the oral flora of patients who underwent tonsillectomy. Pockets were tested for eleven bacterial species before and six weeks after the surgical intervention. METHODS: Fifty generally healthy adults were included in this study. The test group consisted of 25 patients with tonsillectomy. The control group included 25 patients with otorhinolarynologic surgery without involvement of the oral cavity. Clinical parameters such as probing pocket depth, bleeding-on-probing index and plaque index were registered the evening before surgery. Also bacterial samples from the gingival sulcus and dorsum linguae were taken, and an additional sample from the removed tonsils in the test group. Six weeks after the intervention microbial samples of pockets and tongue were taken again. Data were tested for significant differences using Wilcoxon rank and Whitney-u-test. RESULTS: No relevant intra- or intergroup differences were found for the change of the eleven investigated species. CONCLUSION: Based on the results of the present study, tonsillectomy does not seem to have an immediate relevant effect on the bacterial flora of tongue or periodontium. This study design was approved by the ethical committee of Zurich (KEK-ZH-Nr.2013-0419). TRIAL REGISTRATION: The trial was retrospectively registered in the German Clinical Trials Register ( DRK00014077 ) on February 20, 2018.

Zusammenfassung Die effektive Reinigung der Interdentalräume mit Zahnbürsten ist eine Herausforderung. Ziel der vorliegenden In-vitro-Studie war es, die Reinigungseffizienz und gleichzeitig das Gingivaverletzungspotenzial einer elektrischen Schallzahnbürste mit Singlekopf (Waterpik) und zweier Einbüschelbürsten (Curaprox 1009; Lactona Interdental Brush) fur den Interdentalbereich zu untersuchen. Die Bürsten wurden in einer Bürstmaschine evaluiert, indem Testmodelle (Oberkiefersextanten), bei welchen schwarze Modellzähne weiß beschichtet wurden, mit standardisierten horizontalen Bewegungen bearbeitet wurden. Danach wurden die schwarzen (d.h. gereinigten) Flächen planimetrisch erfasst. Das Verletzungspotenzial wurde anhand des Frontsegments von Schweineunterkiefern untersucht. Die Testbürsten wurden wiederum mit der Bürstmaschine über die Gingiva geführt. Vor und nach jeder Behandlung wurde die Schweinegingiva mit einem Plaquerevelator gefärbt. Damit wurden verletzte Gingivastellen/-flächen sichtbar gemacht und vermessen. Die Evaluationen fanden nach jeweils 15, 30, 60 und 120 Sekunden Bürstdauer statt. Die beste Reinigungsleistung über alle gemessenen Interdentalräume zeigte die elektrische Schallzahnbürste mit 46 %, während die Reinigungsleistung der Einbüschelbürste von Lactona 14,8 % betrug und die der Einbüschelbürste von Curaprox 5 %. Die Gingiva wurde zu jedem Untersuchungszeitpunkt am deutlichsten von der elektrischen Schallzahnbürste mit Singlekopf (Waterpik) verletzt, gefolgt von der Einbüschelbürste von Curaprox. Die geringsten Verletzungen der Schweine-gingiva wurden von der Einbüschelbürste von Lactona verursacht. Im Vergleich zwischen den Handzahnbürsten zeigte die letztgenannte Bürste eine besser Reinigungswirkung in Kombination mit einem kleineren Verletzungspotenzial. Das Ziel, einen möglichst hohen Sauberkeitsgrad zu erreichen und dabei wenig Schaden anzurichten, ist also wichtig und sollte bei der Evaluation und Wahl von Zahnbürsten im Vordergrund s

BACKGROUND Generalised aggressive periodontitis (AP) in the prepubescent age is an exceptionally rare disease in the primary dentition of otherwise healthy children. Characteristics of AP are gingival inflammation, deep periodontal pockets, bone loss, tooth mobility and even tooth loss. The most common way of treating this disease is the extraction of all the involved primary teeth. CASE REPORT A 4-year-old girl presented with signs of severe gingival inflammation. Clinical examination revealed deep pockets, increased tooth mobility and bone loss. Microbiological testing revealed the presence of a typical periopathogenic flora consisting of Aggregatibacter actinomycetemcomitans and the typical members of the red complex (Porphyromonas gingivalis, Prevotella intermedia and Treponema denticola). The patient underwent tooth extraction of all primary teeth except the primary canines, followed by thorough root debridement and treatment with systemic antibiotics (amoxicillin plus metronidazole). FOLLOW-UP Regular clinical and microbiological examinations over 4 years showed no signs of recurrence of a periodontitis, even in the erupted permanent teeth. CONCLUSION Early diagnosis and consequent early treatment of aggressive periodontitis can stop the disease and therefore avoid the development of a periodontal disease in the permanent dentition. A close collaboration between specialists of different disciplines is required for a favourable outcome.

OBJECTIVES: The aim of this study is to evaluate the adhesion between PEEK and two self-adhesive resin cements after plasma treatment. METHODS: Eight hundred sixty-four polyetheretherketone (PEEK) disks were cut and polished to silicon carbide (SIC) P4000. One half of the specimens were randomly selected and pretreated with plasma, whereas the remaining 432 specimens remained untreated. Subsequently, specimens were randomly allocated to four groups (n = 108/group): Visio.link (Bredent), Signum PEEK Bond (Heraeus Kulzer), Ambarino P60 (Creamed), and a control group without additional treatment. Half of the specimens of each group (n = 54) were then cemented with either RelyX Unicem Automix 2 (3 M ESPE) or with Clearfil SA (Kuraray). All specimens were stored in water for 24 h (37 °C). Afterwards, specimens were divided into three groups (n = 18) for different aging levels: (1) no aging (baseline measurement), (2) thermal aging for 5,000 cycles (5/55 °C), and (3) thermal aging for 10,000 cycles (5/55 °C). Thereafter, shear bond strengths (SBS) were measured, and failure types (adhesive, mixed, and cohesive) were assessed. Data were analyzed using descriptive statistics, four- and one-way ANOVA followed by a post hoc Scheffé test (p < 0.05). RESULTS: No adhesion could be established without adhesive pretreatment, irrespectively, whether plasma was applied or not. Also, no bond strength was measured when Ambarino P60 was applied. In contrast, adhesive pretreatment resulted in SBS ranging between 8 and 15 MPa. No significant differences were found between the resin cements used. In general, no cohesive failures were observed. Groups without plasma treatment combined with Visio.link or Signum PEEK Bond showed predominantly mixed failure types. Control groups, plasma treated, or treated using Ambarino P60 groups fractured predominantly adhesively. CONCLUSION: The use of methyl methacrylate (MMA)-based adhesives allows bonding between PEEK and self-adhesive resin cements. P