The Application of Virtual Simulation Technology in Scaling and Root Planing Teaching

BACKGROUND

Virtual simulation (VS) technology has been widely utilised in various aspects of oral education. This study aimed to evaluate the impact of VS technology in a scaling and root planing (SRP) teaching programme and explore an effective teaching approach.

METHOD

A total of 98 fourth-year undergraduates from Guanghua School of Stomatology at Sun Yat-sen University were enrolled in this study and randomly assigned to either the VS teaching group or the traditional teaching (TT) group. All participants received SRP training before undergoing an operational examination. Subsequently, questionnaires were administered to both students and teachers involved in the programme to assess the teaching effect and fidelity of the VS training system. Unpaired Student t test was used to analyse the final test scores and residual rates amongst students.

RESULTS

The overall residual rate of the calculus in the VS group was significantly lower than that in the TT group (48.81% ± 13.50% vs 56.89% ± 13.68%, P<.01). The difference was particularly notable in posterior teeth, proximal surfaces, and deep pockets. Additionally, the VS group students achieved higher final grades compared to the TT group (86.92 ± 6.10 vs 83.02 ± 6.05, P<0.01). In terms of teaching effectiveness assessment, the VS group students provided higher scores than the TT group, except in the areas of mastery of position, finger rests, and efficiency.

CONCLUSIONS

The implementation of VS technology demonstrated improvements in students' performance in SRP teaching. Therefore, a novel integrated pedagogic approaches method that combines VS technology with traditional teaching approaches could be further explored in future training programmes.

New design of interdental rubber picks - does the archimedean screw design bring an improvement for experimental cleaning efficacy and force?

BACKGROUND

Up to date, interdental brushes (IDB) are the first choice for interdental cleaning because of their cleaning efficacy. Cylindrical ones must be selected individually according to the size/morphology of the interdental area (IDR), whereas conical ones cover a larger variability of IDR. However, there is a trend on the part of patients towards interdental rubber picks (IRP) which are in general conically shaped, and which seem to be linked with lower cleaning efficacy. A new IRP with an Archimedes´ screw design was developed to overcome this limitation. Therefore, the in vitro study aimed to measure the experimental cleaning efficacy (ECE) and force (ECF) during interdental use of IDBs versus the new IRP type.

METHODS

Three IRPs with different tapers (PHB angled: 0.039, PHB straight S: 0.027, Vitis straight M: 0.045; all Flexipicks, Dentaid, Cerdanyola del Vallès, Spain) were compared to one IDB (Interprox micro PHD 0.9, Dentaid, Cerdanyola del Vallès, Spain). IDR were reproduced by a 3D-printer (Form2, Formlabs Sommerville, MA, USA) according to human teeth and matched to equivalent pairs (isosceles triangle, concave, convex) in three different diameters (1.0 mm,1.1 mm,1.3 mm). Covered with simulated biofilm, pre-/ post-brushing situations of IDR (standardized, computer-aided ten cycles) were photographed and quantified by digital image subtraction to calculate ECE [%]. ECF were registered with a load cell [N]. Statistically significant differences were detected using the Mann-Whitney-U-test and the Kruskal-Wallis-test with Bonferroni correction for multiple testing.

RESULTS

Overall, the ECE (mean ± SD) was higher for IDB micro 0.9 (45.95 ± 11.34%, p < 0.001) compared to all IRPs (PHB angled: 25.37 ± 15.29%; PHB straight: 22.28 ± 16.75%; Vitis straight: 25.24 ± 12.21%; p ≤ 0.001), whereat best ECE was achieved in isosceles triangle IDR of 1.0-1.1 mm (IDB micro 0.9: 70.7 ± 7.7%; PHB angled S: 57.30 ± 4.43%; p < 0.001). The highest ECF occurred for Vitis straight M with 2.11 ± 0.46 N, while IDB micro 0.9 showed lowest ECF values (0.64 ± 0.14 N; p < 0.001).

CONCLUSIONS

IRP with an Archimedes´ screw design and a higher taper were associated with advanced ECE but also higher ECF, nevertheless, ECE didn't reach the cleaning efficacy of conventional IDBs.

Laser light: Illuminating the path to enhanced periodontal care

The utilisation of laser technology in the realm of periodontal care represents a significant advancement in clinical practice. This article delves into the historical context of laser therapy in medicine, from its inception in 1960 to its evolution into low-level laser therapy (LLLT). LLLT, often referred to as photobiomodulation (PBM), has garnered attention due to its potential to enhance periodontal treatment outcomes. The article thoroughly examines the mechanisms of action of photobiomodulation therapy PBM(T), covering its impact on cellular and tissue levels. The authors explore the evidence-based recommendations for the use of PBM(T) in periodontal care, shedding light on its potential to improve periodontal conditions, especially when applied as an adjunct to conventional treatments. They investigate the role of PBM(T) in individuals and its possible contribution to periodontal health. Additionally, the article delves into its application in periodontal regenerative procedures and its ability to expedite soft tissue wound healing and the effects of PBM(T) in reducing periodontal inflammation and mitigating post-periodontal surgery discomfort. In conclusion, the article calls for enhanced clinical research to streamline laser procedures, develop antimicrobial photodynamic therapy, and conduct well-designed randomised controlled trials (RCTs). It also emphasises the importance of understanding the impact of laser therapy on therapeutic and biological goals, the potential to reduce invasive procedures, and the necessity of adequate research funding.

Management of interdental papillary defects using subperiosteal hyaluronic acid injection overlay technique: a prospective longitudinal clinical study

OBJECTIVE

Currently, there is no established treatment protocol to treat Interdental papillary loss. This research aimed to evaluate the outcomes of interdental papillary reconstruction using minimally invasive surgery, with injectable hyaluronic acid (HA) gel.

MATERIALS AND METHODS

Seventeen patients were included, each with five sites of class 1 papillary recession; (forty sites in the upper jaw and forty-five sites in the lower jaw). Subperiosteal tunneling was performed through a horizontal incision made apical to the base of the papilla without penetrating it. The free gingival sulcus was sealed by 000 retraction cord. After that a total of 0.2-0.6 mL HA was injected gradually. The incision was sutured with polyglycolic sutures. Treated sites underwent clinical and digital evaluation at three follow up time points (1 month, 3 months and 6 months).

RESULTS

The interdental papillary defect height in the upper jaw sites significantly reduced by 60%, 66%, and 42% at 1 month, 3 and 6 months, respectively. Also, in lower jaw sites, the reduction was of about 54%, 55%, and 40% at the same follow up time points. Regarding interdental papillary defect surface area in the upper jaw the reduction was about 65%, 71%, and 45% at 1 month, 3 and 6 months. In the lower jaw, a reduction of about 60%, 64%, and 48% was noticed at the same time points. Regarding patients' pain level score, during the day of surgery, sixteen patients reported pain, the average pain score out of 10 was 3.94, and eleven patients (64.7%) needed to take analgesics. The pain generally subsided in the following days. Also, at the day of the treatment twelve out of the seventeen patients (70.6%) reported mild difficulty in speaking and eating. No complication, hypersensitivity or allergy was noted in any patient.

CONCLUSION

Subperiosteal tunneling with HA injection demonstrates clinical improvements in papilla height and papillary recession surface area reduction after 3 months of follow-up with reduction in improvement after 6 months.

Use of over-the-counter mouthwashes as an additional measure in individual oral prophylaxis on adults with plaque-induced gingivitis: a double-blind, parallel, randomized controlled trial

BACKGROUND

Plaque-induced gingivitis is a chronic inflammatory condition characterized by complete reversibility of tissue damage once the periodontal biofilm has been disorganised. The aim of this study was to evaluate the efficacy of two commercially available mouthwashes (MWs) versus a chlorhexidine (CHX) 0.12% MW in reducing gingival bleeding (GB) in adults with plaque-induced gingivitis.

METHODS

The present study was a double-blind, parallel, randomized controlled trial involving 6492 gingival sites (i.e. 39 subjects × 28 teeth × 6 sites/tooth) aged 18-75 years. During a 2-week period, subjects were randomized to receive MWs: a control CHX 0.12% MW (group C, 1818 sites); a MW test containing CHX 0.09% + Citrox®/P complex (group CX, 2628 sites); a MW test based on natural compounds (group P, 2016 sites). GB was assessed at the inclusion visit (T0) and after 2 weeks of MW use (T1). Analyses of GB were compared between groups and then restricted to subjects with bleeding sites between 10 and 30% (moderate gingivitis) or ≥ 30% (severe gingivitis) at T0. Pairwise comparisons were made between groups and logistic regression was used to identify correlates of GB (T1).

RESULTS

For total bleeding site analysis, GB reduction between T0 and T1 ranged from 23% (C), 26% (CX) and 36% (P), respectively (all p < 0.05). Multiple comparison between groups showed that group C was significantly less effective (p < 0.05) than groups CX and P. Splitting the analysis, in patients with severe gingivitis (≥ 30% bleeding sites at T0), all MWs had a positive effect on GB with a reduction at T1 of 36% (C), 33% (CX) and 42% (P), respectively. While GB reduction between T0 and T1, was significant for all groups, the comparison among groups showed no significant difference between group C and CX, whereas the improvement was significant for group P. On the other hand, in adults with moderate gingivitis (< 30% bleeding sites at T0), only CX and P had a positive effect on GB reduction at T1(9% in CX and 2% in P, respectively), although the differences between the three groups were not significant.

CONCLUSION

The daily use of MWs with natural components (groups P and CX) for 2 weeks should be considered positively as an adjunct to individual oral prophylaxis to reduce GB compared to the control MW containing CHX 0.12% (group C) in healthy adults with plaque-induced gingivitis. For subjects with severe gingivitis, it is advisable to first use natural MW (P) and then MW based on CHX 0.09% with natural components (CX), compared to MW with CHX 0.12% (C). For adults with moderate gingivitis, P and CX can be advisable, even if no definitive recommendations can be drawn.

TRIAL REGISTRATION

ACTRN12622000215729, 07/02/2022.

Thermographic examination of gingival phenotypes: correlation between morphological and thermal parameters

OBJECTIVES

To evaluate the clinical and thermographic aspects of the gingival phenotype (GP) in healthy subjects.

MATERIALS AND METHODS

The study sample examined 264 teeth, upper and lower incisors, comprising 132 central incisors (CI) and 132 lateral incisors (LI), in 33 healthy volunteers. Four periodontal parameters were recorded systematically: ratio of width to length of the dental crown (CW/CL), height of the gingival attachment (KGW), probing depth (PD), and gingival transparency (GT). The temperatures of the attached gingiva (KGW temp) and the free gingival margin (FGM Temp) were also recorded by way of infrared thermography (IRT).

RESULTS

The average age of the sample was 30.70 ± 7.65 years. Of the 264 teeth evaluated, 76.1% had a thin GP. There was a significant association between CW/CL (p < 0.001), KGW (p < 0.001), PD (p < 0.007), and FGM Temp (p < 0.006) with the tooth groups. The results show a significant and inversely proportional correlation between clinical parameters and gingival temperature (p < 0.05). A significant association was found between CW/CL (p < 0.026); KGW (p < 0.001); and GP.

CONCLUSION

CW/CL, KGW, PD, and FGM Temp vary according to tooth group. The majority of the sample presented with the thin GP, which was more prevalent in the lower LIs and CIs. No significant association could be observed between thermographic parameters and GP.

CLINICAL RELEVANCE

Knowledge of the temperature of the gingival tissues can be useful in helping to diagnose and plan periodontal treatments. Moreover, our findings will help future studies evaluate the use of IR as an auxiliary diagnostic method in dentistry, eliminating GP as a confounding factor, since it does not seem to influence the temperature of the gingival tissues.

Technical considerations in obtaining platelet rich fibrin for clinical and periodontal research

Autologous platelet rich fibrin (PRF), is currently being widely used and investigated across the globe by clinicians and periodontal research. The technical aspect required for the procurement of PRF includes revolution per minute (RPM), relative centrifugal force (RCF) or G-force, rotor radius, rotor angle, stability or vibration in the centrifugal machine and material of test-tube, besides the systemic health of the individual may influence the final outcome. Present technical note intends to compile these aspects for better understanding and appropriate outcome while preparing PRF in varying clinical scenarios.

Gingival biotype modification with collagen matrix or autogenous subepithelial connective tissue graft: Histologic and volumetric analyses in a beagle model

Objectives

To evaluate the volumetric effect and biocompatibility of porcine tendon-derived type I collagen matrix graft (CG) in gingival biotype modification (GBM) compared with subepithelial connective tissue graft (SCTG) in a beagle model.

Methods

Surface analysis using scanning electron microscopy and a collagen degradation assay of CG was performed in vitro. Six adult dogs were used in in vivo experiment, and each received autologous SCTG or CG at the anterior side. Histometric and three-dimensional digital volume analyses were conducted to compare quantitative changes in CG and SCTG in GBM. Immunohistochemical analysis was performed for the qualitative evaluation of CG compared to SCTG.

Results

CG had a double-layered structure, and its degradation was slower than that of other well-reported materials. No critical problems were associated with the healing procedure. Changes in gingival thickness and volume in the CG and SCTG groups were equivalent, with no significant differences between the groups. Type I collagen and vascular endothelial growth factor expression levels were similar in both groups.

Significance

CG and SCTG had equivalent potential for GBM in terms of quantity and quality. Additionally, CG could be used as a reasonable substitute for SCTG, making surgery convenient and predicting successful clinical outcomes.

The evaluation of gingival phenotype using visual inspection method by clinicians

OBJECTIVES

Evaluating gingival thickness is an essential factor for aesthetic, function, and the maintenance of soft tissue health around natural teeth and dental implants. This study aimed to evaluate the accuracy of visual inspection procedures used to identify gingival phenotype by clinicians with different expertise and level of experience.

METHOD AND MATERIALS

The gingival phenotypes of a total of two hundred cases were identified as either thick or thin via visual assessment with clinical photographs by eight clinicians. One periodontist examined the gingival phenotype of all subjects based on the translucency of the periodontal probe through the gingival sulcus. The accuracy between these two methods was evaluated using percentile agreement and k statistics.

RESULTS

The mean percentage of accurately identified cases was seventy-five percent of the cases irrespective of the clinician's experience and expertise. Almost half of the thin phenotype cases were misclassified by clinicians. İnter-examiner agreement was generally fair to moderate and intra-examiner agreement was generally moderate.

CONCLUSION

Within the limits of this study, the present findings demonstrated that the visual inspection method misclassified the cases, especially thin gingival phenotype, compared to the probe translucency method. Therefore, there is a need for identifying a universally accepted, accurate method and clear clinical definitions.

Root coverage surgery for dentin hypersensitivity reduction: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

To evaluate the effectiveness of root coverage surgery in reducing dentin hypersensitivity (DH) through a systematic review and meta-analysis.

DATA SOURCES

Unrestricted search of four indexed databases up to September 2022 was performed to identify randomized controlled trials (RCTs) evaluating the effect of root coverage surgery on DH frequency and/or intensity pre-surgically (baseline) and at least 3 months post-surgically. Two authors independently conducted study screening and data extraction. Subgroup meta-analyses were performed separately for stimulated and unstimulated DH frequency and intensity at different timepoints. The risk of bias and quality of the available evidence were assessed.

RESULTS

Nineteen RCTs presenting data from 7 days to 30 months after root coverage surgery with various treatment modalities were included from the 662 identified studies. A total of 486 patients contributed 784 recession defects. Results from the subgroup meta-analyses showed that, overall, root coverage surgery reduced the risk for DH by 67% (RR 0.33, CI: [0.21-0.53]) and 53% (RR 0.47, CI: [0.38-0.58] upon unstimulated and stimulated DH assessment, respectively. The DH intensity was also significantly reduced (mean VAS score difference: 2.37, CI: [2.02-2.71]) upon stimulated DH assessment. No significant changes in DH intensity were observed upon unstimulated DH assessment. The included studies did not have high risk of bias and the quality of evidence was low to high.

CONCLUSION

Existing evidence suggests that root coverage surgery may effectively reduce the DH frequency and intensity.

Erbium-doped yttrium aluminum garnet laser and advanced platelet-rich fibrin+ in periodontal diseases: Two case reports and review of the literature

BACKGROUND

The goal of periodontal disease treatment is to completely remove bacteria and promote wound healing. The erbium-doped yttrium aluminum garnet (Er:YAG) laser is commonly used to treat periodontal disease. Advanced platelet-rich fibrin+ (A-PRF+) secrets growth factors that accelerates soft- and hard-tissue regeneration and wound healing. Herein I present 2 cases of patients with oral diseases treated with a combination of Er:YAG laser and A-PRF+.

CASE SUMMARY

Case 1 was a female with pocket depth bone loss over 8 mm and infection of tooth 31 and 41, and severe advanced periodontitis with grade III mobility. Case 2 was a male with tooth 22 root end apical swelling and infection and alveolar bony defects. Clinical outcomes were recorded at 6 and 36 mo. In case 1, the Er:YAG laser was used to perform open flap debridement (100 mJ/pulse, 15 Hz) and remove calculus and granulation tissue (50 mJ/pulse, 30 Hz). In case 2 the laser was used to create a semilunar full thickness flap incision (80 mJ/pulse, 20 Hz) and eliminate the pathogen (100 mJ/pulse, 15 Hz). In both patients, A-PRF+ mixed with bone was used to fill bone defects, and A-PRF+ autologous membranes were used to cover tension-free primary flaps. There was no recurrent infection at 36 mo, and tissue regeneration and would healing occurred.

CONCLUSION

Debridement with an Er:YAG laser followed by treatment with A-PRF+ is effective for the treatment periodontal diseases with bone defects.

Management of the palato-radicular groove with a periodontal regenerative procedure and prosthodontic treatment: A case report

BACKGROUND

Palato-radicular groove (PRG) is defined as an anomalous formation of teeth. The etiology of PRG remains unclear. The prognosis of a tooth with a PRG is unfavorable. The treatment of combined periodontal-endodontic lesions requires multidisciplinary management to control the progression of bone defects. Some researchers reported cases that had short-term observations. The management of teeth with PRGs is of great clinical significance. However, to date, no case reports have been documented on the use of bone regeneration and prosthodontic treatment for PRGs.

CASE SUMMARY

This case reported the management of a 40-year-old male patient with the chief complaint of slight mobility and abscess in the upper right anterior tooth for 15 d and was diagnosed with type II PRG of tooth 12 with combined endodontic-periodontal lesions. The accumulation of plaque and calculus caused primary periodontitis and a secondary endodontic infection. A multidisciplinary management approach was designed that included root canal therapy, groove sealing, a periodontal regenerative procedure, and prosthodontic treatment. During a 2-year follow-up period, a good prognosis was observed.

CONCLUSION

This report indicates that bone regeneration and prosthodontic treatment may contribute to the long-term favorable prognosis of teeth with PRGs.

The applications of ultrasound, and ultrasonography in dentistry: a scoping review of the literature

OBJECTIVES

This scoping review aims to summarize the available literature on the clinical applications of ultrasonography and ultrasound in diagnostic, therapeutic, and interventional dental applications.

MATERIALS AND METHODS

We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, Extension for Scoping Reviews checklist and conducted a protocol-driven scoping review of randomized controlled trials, cohort studies, cross-sectional studies, case-control studies, and case series that assessed ultrasonography or ultrasound use as a stand-alone diagnostic, therapeutic, and interventional tool in dentistry. We included studies published after 1980, study samples ≥ 10, with diagnostic, concordance, or therapeutic outcomes. We searched Ovid MEDLINE, Embase, and others (up to April 2021) and extracted information regarding study level, patient level, test or treatment level, and outcome level data.

RESULTS

Five interventional studies (related to oral medicine, temporomandibular disorders, and dental anesthesia), eight therapeutic studies (related to surgery and orthodontics), and seventy-five diagnostic studies (related to orthodontics, surgery, endodontics, oral medicine, temporomandibular disorders, restorative dentistry, and periodontology) were identified and presented in this review.

CONCLUSION

Ultrasonography has a well-established niche in diagnostic dentistry, while therapeutic and interventional ultrasounds have a smaller, yet present, niche in dentistry. However, further research is needed to report the precise estimates of the diagnostic, therapeutic, and interventional effects.

CLINICAL SIGNIFICANCE

Dentists are mostly unfamiliar with ultrasonography and ultrasound and their potential uses. This review maps the diagnostic and therapeutic applications of ultrasonography and ultrasound technology in dentistry and highlights the current challenges, gaps of knowledge, and research status of ultrasound technology in this regard.

An educational approach for early student self-assessment in clinical periodontology

BACKGROUND

Self-assessment is a mandated educational requirement for use in dental undergraduate programmes. It is weakly supported for use in early clinical training and studies are criticized for the conceptual and methodology shortfalls. The aim of the study was to compare the alignment of student self-assessment to both staff assessment and written exams in early clinical training using an educational approach.

METHODS

In 2014-2015, 55 third-year dental students completed three educational sessions comprising of (a) classroom teaching (lecture, video) with post-lesson written exam and (b) clinical activity with student self-assessment, staff assessment and student reflection. An intra-individual analysis approach, staff validation, and student scoring standardization were implemented. Cognitive (clinical competency) and non-cognitive (professionalism) items were separated in the analyses.

RESULTS

There were medium correlations (Spearman's rho, r) between student self-assessment and staff assessment scores for cognitive items (r, 0.32) and for non-cognitive items (r, 0.44) for all three combined sessions. There were large correlations for individual sessions. Compared to the post-lesson written exam, students showed small correlation (r, 0.22, 0.29) and staff showed medium correlation (r, 0.31, 0.34) for cognitive and non-cognitive items. Students showed improvements in their mean scores for both cognitive (t-test; p > 0.05) and non-cognitive items (t-test; p = 0.000). Mean scores of students were not different statistically from that of staff (p > 0.05).

CONCLUSIONS

Students may adequately act as self-assessors at the beginning of their clinical work in periodontology. Self-assessment may potentially improve the clinical performance. Self-assessment may be nurtured through clear guidelines, educational training strategies, feedback and reflection leading to better evaluative judgement and lifelong learning.

Estimation of periodontal pocket surface area in small to medium dogs: a proof-of-concept study

Background

Periodontal disease is the most common dental disease in dogs. Although the systemic effects of periodontal disease have not been clarified in veterinary science, it is necessary to evaluate the effects of periodontal disease in clinical trials in the future. There have been a few clinical attempts made, however, to assess the severity of periodontal inflammation and its impact on the systemic health of dogs. Meanwhile, in the field of dentistry for humans, the periodontal inflamed surface area (PISA) and periodontal epithelial surface area (PESA) have been used to quantitatively assess the degree of periodontal disease affecting a single tooth as well as the overall extent of periodontitis. Recent studies have also suggested the use of these assessments to examine the relationship between periodontal inflammation and systemic health.

Results

The estimation formula for a dog’s periodontal pocket surface area (PPSA), an alternative to PISA and PESA in humans, was established using body weight and periodontal pocket depth. Actual values were measured using extracted teeth from various dog breeds and sizes (2.3–25.0 kg of body weight) to obtain universal regression equations for PPSA. Altogether, 625 teeth from 73 dogs of 16 breeds were extracted and subsequently analyzed for morphological information.

PPSA was measured in 61 dogs of 10 breeds with periodontal disease using the established estimation formulas, and the correlation between PPSA and preoperative blood chemistry data was analyzed accordingly. A strong correlation was found between PPSA and serum globulin (r = 0.71) while moderate correlations were found for C-reactive protein (r = 0.54) and serum albumin (r = -0.51).

Conclusions

Estimation formulas using body weight and the 6-point probing depth were established for determining PPSA. Direct correlations between PPSA and several blood test results were observed in the study sample. Taken together, these results suggest that PPSA could be useful for evaluating the effects of periodontitis on systemic conditions in dogs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-021-03116-0.

Effectiveness of virtual simulation and jaw model for undergraduate periodontal teaching

BACKGROUND

The current study explored the effect of virtual simulation and jaw model on development of preclinical periodontal skills in undergraduate students. The study also sought to explore effectiveness of VR in periodontal preclinical training and determine adequate performance mode in basic periodontal education to improve future preclinical training strategies.

METHODS

Sixty volunteer sophomores and juniors from the stomatology department in Lanzhou university were enrolled to the current study. Participants were randomly assigned into four groups (each group, n = 15) including the traditional jaw model group (Group J) which was the control group, virtual reality group (Group V), virtual-jaw group (Group V-J), and jaw-virtual group (Group J-V). Participants received training on uniform basic periodontal knowledge before completing the first theoretical assessment. Participants further underwent a total 8 h of operation training and completed a second theoretical assessment. Performance of participants was evaluated using the supragingival scaling processes, and clinical operation scores were graded by a blinded professional using an established standard scoring system.

RESULTS

The findings showed no significant difference in the first theoretical outcomes between the four groups (P > 0.05). The scores of the second theoretical assessment were significantly improved for the V-J and J-V groups (60.00 ± 4.47, 58.33 ± 4.35) compared with the scores of the first theoretical exam (49.67 ± 4.81, 48.00 ± 4.93, P < 0.05). The operation process scores of students in Group V-J and J-V (72.00 ± 5.92; 70.00 ± 3.05) were significantly higher compared with the scores in the other two groups (V: 61.67 ± 7.85; J: 60.67 ± 2.58). The scaling process performance of students in Group V-J and J-V (53.00 ± 3.05; 63.40 ± 4.39) was improved compared with that of students in the other two groups (V: 41.90 ± 5.23; J: 47.40 ± 4.31).

CONCLUSION

The findings show that combination of virtual reality and jaw model during periodontal preclinical training increases students' grades and improves acquiring of professional skills. Findings from the current study indicate that the jaw model should be applied prior to virtual reality to ensure high efficacy.

Cellular effects of glycine and trehalose air-polishing powders on human gingival fibroblasts in vitro

Objectives

Air-polishing has been used in the treatment of periodontitis and gingivitis for years. The introduction of low-abrasive powders has enabled the use of air-polishing devices for subgingival therapy. Within the last decade, a wide range of different low-abrasive powders for subgingival use has been established. In this study, the effects of a glycine powder and a trehalose powder on human gingival fibroblasts (HGF) were investigated.

Methods

HGF were derived from three systemically and periodontally healthy donors. After 24 h and 48 h of incubation time, mRNA levels, and after 48 h, protein levels of TNFα, IL-8, CCL2, and VEGF were determined. In addition, NF-κB p65 nuclear translocation and in vitro wound healing were assessed. Statistical analysis was performed by ANOVA and post hoc Dunnett’s and Tukey’s tests (p < 0.05).

Results

Glycine powder significantly increased the expression of proinflammatory genes and showed exploitation of the NF-κB pathway, albeit trehalose powder hardly interfered with cell function and did not trigger the NF-κB pathway. In contrast to trehalose, glycine showed a significant inhibitory effect on the in vitro wound healing rate.

Conclusion

Subgingivally applicable powders for air-polishing devices can regulate cell viability and proliferation as well as cytokine expression. Our in vitro study suggests that the above powders may influence HGF via direct cell effects. Trehalose appears to be relatively inert compared to glycine powder.

Clinical relevance

With the limitations of an in vitro design, our study suggests that in terms of cell response, trehalose-based air-polishing powders show a reduced effect on inflammation.

Combination of bone substitutes and vectors in periodontology and implantology: A systematic review

The aim of the systematic review was to analyze the use of combination of bone substitutes and vectors in periodontology and implantology among animals models and humans. Electronic databases were searched, and additional hand search was performed. The research strategy was achieved according to the PRISMA guidelines. The including criteria were: combination of bone substitutes and vectors, in vivo studies, a precise number of specimens, histological and radiographic analysis, written in English. The risk of bias was evaluated for individual studies. Thirty-two articles were selected and investigated in this systematic review. The results do not show a superiority of the use of composite biomaterial in comparison with simple biomaterial but suggest the efficacity of their utilization as a carrier of bioactive agents. Future studies need to identify the suitable association of bone substitutes and vectors and explore interest in their use such as the support of growth factors.

Current advances of epigenetics in periodontology from ENCODE project: a review and future perspectives

BACKGROUND

The Encyclopedia of DNA Elements (ENCODE) project has advanced our knowledge of the functional elements in the genome and epigenome. The aim of this article was to provide the comprehension about current research trends from ENCODE project and establish the link between epigenetics and periodontal diseases based on epigenome studies and seek the future direction.

MAIN BODY

Global epigenome research projects have emphasized the importance of epigenetic research for understanding human health and disease, and current international consortia show an improved interest in the importance of oral health with systemic health. The epigenetic studies in dental field have been mainly conducted in periodontology and have focused on DNA methylation analysis. Advances in sequencing technology have broadened the target for epigenetic studies from specific genes to genome-wide analyses.

CONCLUSIONS

In line with global research trends, further extended and advanced epigenetic studies would provide crucial information for the realization of comprehensive dental medicine and expand the scope of ongoing large-scale research projects.

There is still room for improvement in the completeness of abstract reporting according to the PRISMA-A checklist: a cross-sectional study on systematic reviews in periodontology

BACKGROUND

To evaluate the completeness of reporting abstracts of systematic reviews (SRs) before and after the publication of the PRISMA-A checklist in 2013 and to assess if an association exists between abstract characteristics and the completeness of reporting.

METHODS

A systematic search of the literature was conducted in the PubMed and Scopus databases in March 2020. The search focused on the SRs of evaluations of interventions published since 2002 in the field of periodontology. The abstracts of the selected SRs were divided into two groups before and after publication of the PRISMA-A checklist in 2013, and compliance with the 12 items reported in the checklist was evaluated by three calibrated evaluators.

RESULTS

A set of 265 abstracts was included in the study. The total score before (mean score, 53.78%; 95% CI, 51.56-55.90%) and after (mean score, 56.88%; 95% CI, 55.39-58.44%) the publication of the PRISMA-A statement exhibited a statistically significant improvement (P = 0.012*). Nevertheless, only the checklist items included studies and synthesis of the results displayed a statistically significant change after guideline publication. The total PRISMA-A score was higher in the meta-analysis group and in articles authored by more than four authors.

CONCLUSIONS

The impact of the PRISMA-A was statistically significant, but the majority of the items did not improve after its introduction. The editors and referees of periodontal journals should promote adherence to the checklist to improve the quality of the reports and provide readers with better insight into the characteristics of published studies.

Local delivery natural products to treat periodontitis: a systematic review and meta-analysis

OBJECTIVES

This study aimed to answer the PICO question: in adults with periodontitis, does subgingival delivery of natural products (NP) after scaling and root planing (SRP) results in a better reduction of probing pocket depth (PPD) when compared with SRP alone or SRP plus placebo?

MATERIAL AND METHODS

A search for trials was carried out in eight databases. Two independent investigators performed all steps of this review. PPD reduction, clinical attachment level (CAL) gain, gingival inflammation, and biofilm accumulation reduction were investigated. We conducted meta-analyses where data could be pooled.

RESULTS

Searches yielded 4771 records, in which 27 trials fulfilled the eligibility. There was a large heterogeneity among trials (I² > 0.69, χ² < 0.000). Only four studies were at low risk of bias. The evidence quality was very low. The effectiveness of NP was demonstrated in a follow-up of 3-6 months considering PPD reduction (8 trials: 0.72 mm [95%CI: 0.23, 1.22]) and CAL gain (5 trials: 1.07 mm [95%CI: 0.36, 1.78]). A significant reduction in periodontal inflammation favors the use of NP. The biofilm accumulation reduction effect of NP was very weak or non-significant.

CONCLUSION

Although the high risk of bias and large heterogeneity of trials impose some restrictions on the validity of effect estimate, this review indicates that adjunctive NP better reduced the PPD when compared to SRP alone or SRP plus placebo in a follow-up of 3-6 months.

CLINICAL RELEVANCE

The evidence of non-responsive patients to conventional periodontal therapy highlights the need for therapeutic alternatives to treat periodontitis.

Prospective randomized clinical trial evaluating the effects of two different implant collar designs on peri-implant healing and functional osseointegration after 25 years

OBJECTIVES

Evaluate the effects of two different machined-collar lengths and designs on peri-implant healing.

MATERIAL AND METHODS

An implant with a microtextured surface and 3.6mm-long internal-connection machined collar was compared to two implants that had an identical 1.2mm-long external-connection machined collar, but one had the microtextured surface while the other's was machined. Participants received the three implants, with microgap at the crest, alternately at five sites between mental foramen, and a full-arch prosthesis. Peri-implant bone levels were measured after 23 to 26 years of function. Keratinized tissue height, plaque, probing depth, bleeding, and purulence were also evaluated. Descriptive and mixed models for repeated\measures analyses were used, with Bonferroni correction for pairwise comparisons.

RESULTS

Twenty-two participants (110 implants) were evaluated at the 25-year examination. Microtextured implants with the longer machined collar had significantly greater mean marginal bone loss (-1.77mm ± 0.18, mean ± SE) than machined (-0.85mm ± 0.18, p < .001) and microtextured (-1.00 ± 0.18mm, p < .001) implants with the shorter machined collar. Keratinized tissue height was greater for internal-connection (0.74mm ± 0.10) versus external-connection (0.51 ± 0.08, p =  0.01) microtextured implants. No differences were observed for plaque (p = 0.78), probing depth (p = 0.42), bleeding (p  = 0.07), and purulence (p = 1.00). Implant survival rate was 99%.

CONCLUSIONS

Implants with the 1.2mm machined collar limited bone loss to 1mm, while those with the longer machined collar showed > 1.5mm loss after 25 years of function with microgap at the crest. Internal-connection design and fixture surface microtexturing did not result in greater bone preservation. ClinicalTrials.gov Identifier: NCT03862482.

Discrepancies in periodontitis classification among dental practitioners with different educational backgrounds

Background

The 2018 classification of periodontal disease characterizes the disease with a multidimensional staging and grading system. The purpose of this multicenter study was to examine variations in periodontitis classification among dental practitioners with different postgraduate educational backgrounds at the University of Maryland School of Dentistry and the Loma Linda University School of Dentistry using the 2018 classification.

Methods

This cross-sectional observational study included two cohorts: dental practitioners with periodontal backgrounds (n₁ = 31) and those with other educational backgrounds (n₂ = 33). The survey instrument contained three periodontitis cases presented with the guideline of the 2018 classification and a questionnaire including closed and open-ended questions. The participants were asked to review each case and to fill out the questionnaire independently. Fisher’s exact test was conducted to examine the differences in responses between the two cohorts. Polychoric correlations were calculated to examine the relation between the level of familiarity with the 2018 classification and the accuracy of the classification.

Results

The distribution of item responses was significantly different between the two cohorts regarding only one item, grading for Case 1 (p = 0.01). No significant differences in accuracy between the two cohorts were observed except for two items, grading in Case 1 (p = 0.03) and staging in Case 3 (p = 0.04). There were no significant differences in risk factor identification for each case among the two cohorts (p = 1.00, Case 1; p = 0.22, Case 2). Staging in Case 3

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Conclusion

A fair level of agreement in periodontitis classification was observed among dental practitioners with different educational backgrounds when the 2018 classification was used. The periodontal cohort showed better agreement levels and partially better accuracy. Risk factor identification for periodontal disease was difficult regardless of the educational background.

Perio-Endo Lesions: A Guide to Diagnosis and Clinical Management

Dentists are likely to encounter lesions that have both periodontal and endodontic aetiological components; the so called 'perio-endo lesions'. A thorough examination with appropriate investigations remains pivotal to diagnosing a perio-endo lesion. Correct diagnosis of such lesions is therefore important as it enables the most suitable clinical management to be treatment planned. It is still recommended that for the treatment of perio-endo lesions, initial endodontic therapy is completed.

Use of digital periodontal data to compare periodontal treatment outcomes in a practice-based research network (PBRN): a proof of concept

Background

Scientific studies in dentistry are mainly conducted at universities. However, most patients are treated in dental practices, which differ in many ways from treatment at the university. Through the establishment of practice-based research networks, however, it is also possible to examine studies in a real-world setting in dental practices. For this reason the aim of this non-interventional, observational study was to develop and evaluate a digital procedure to access, extract and analyse recorded clinical data in practices to assess periodontal treatment outcomes.

Methods

Participating periodontists were former or active postgraduate students of a master’s course in periodontics in Freiburg who routinely used a digital periodontal diagnostic program. All available stored periodontal patient charts were extracted, anonymized and digitally sent to the study centre.

Results

In this study, data were collected from 6301 patients from 9 different practices. Information such as probing depth (PD), bleeding on probing (BOP), mobility, furcation and gingival attachment for 153,163 teeth at first visit were successfully transferred to the study centre. During the average observational period of 9.77 years, only 2.8% of all teeth were lost. The number of visits was significantly negatively correlated with BOP (p < 0.0001), and the number of BOP-positive sites was significantly correlated with deeper PDs (p < 0.001).

Conclusion

The presented procedure was able to gather a large amount of practice-based periodontal data, and thus this study may support practice-based research networks. The data indicate that systematic and supportive periodontal therapy is successful on a practice-based level.

Trial registration The study was internationally registered on 4 January 2017 in the German Clinical Trials Register (DRKS 00011448). https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00011448

Underscreening and undertreatment? Periodontal service provision in very old Germans

Objectives

We aimed to assess periodontal services utilization in very old Germans.

Methods

A comprehensive sample of very old (≥ 75 years), insured at a large Northeastern statutory insurer was followed over 6 years (2012–2017). We assessed periodontal service provision, entailing (1) periodontal screening index (PSI), (2) periodontal status/treatment planning, (3) periodontal therapy (scaling and root planning with or without access surgery), (4) postoperative reevaluation, and (5) any of these four services groups. Association of utilization with (1) sex, (2) age, (3) region, (4) social hardship status, (5) ICD-10 diagnoses, and (6) diagnoses-related groups was explored.

Results

404.610 individuals were followed; 173,733 did not survive follow-up. The mean (SD) age was 81.9 (5.4) years. 29.4% (119,103 individuals) utilized any periodontal service, nearly all of them the PSI. Periodontal status/treatment planning, treatment provision, and reevaluation were provided to only a small fraction (1.54–1.57%, or 6224–6345) of individuals. The utilization of the PSI increased between 2012 and 2017; no such increase was observed for treatment-related services. Utilization decreased with age; those aged > 85 years received nearly no services at all. Decreases were more pronounced for treatment-related services. Utilization was lower in rural than urban areas, those with hardship status, and those severely ill (e.g., dementia, heart insufficiency). In multivariable analysis, a previous PSI measurement tripled the odds of receiving treatment-related services (OR: 3.2; 95% CI: 3.0-3.4).

Conclusions

Periodontal services utilization was low. Screening for periodontal disease significantly increased therapy provision. Social, demographic, regional, and general health aspects were associated with utilization.

Clinical significance

The utilization of periodontal services in the very old in Northeast Germany was low, and even screening was only performed in a minority of individuals. Policies to increase identification and management of periodontitis especially in the most vulnerable individuals are needed.

Electronic supplementary material

The online version of this article (10.1007/s00784-020-03635-4) contains supplementary material, which is available to authorized users.

Antimicrobial effect of nanostructured membranes for guided tissue regeneration: an in vitro study

OBJECTIVE

The purpose of this in vitro study was to evaluate the antibacterial effect of a novel non-resorbable, bioactive polymeric nanostructured membrane (NMs), when doped with zinc, calcium and doxycycline.

METHODS

A validated in vitro subgingival biofilm model with six bacterial species (Streptococcus oralis, Actinomyces naeslundii, Veillonela parvula, Fusobacterium nucleatum, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans) was used. The experimental NMs, with and without being doped with doxycycline, calcium and zinc, were placed on hydroxyapatite (HA) discs. As positive control membranes, commercially available dense polytetrafluoroethylene (d-PTFE) membranes were used and, as negative controls, the HA discs without any membrane. The experimental, positive and negative control discs were exposed to a mixed bacterial suspension, at 37 °C under anaerobic conditions, during 12, 24, 48 and 72 h. The resulting biofilms were analyzed through scanning electron microscopy (SEM), to study their structure, and by quantitative polymerase chain reaction (qPCR), to assess the bacterial load, expressed as colony forming units (CFU) per mL. Differences between experimental and control groups were evaluated with the general linear model and the Bonferroni adjustment.

RESULTS

As shown by SEM, all membrane groups, except the NMs with doxycycline, resulted in structured biofilms from 12-72 hours. Similarly, only the membranes loaded with doxycycline demonstrated a significant reduction in bacterial load during biofilm development, when compared with the control groups (p < 0.001).

SIGNIFICANCE

Doxycycline-doped nanostructured membranes have an impact on biofilm growth dynamics by significant reducing the bacterial load.

Clinical, microbiological, and immunological evaluation of patients in corrective orthodontic treatment

Background

The objective was to analyze clinical, microbiological, and immunological periodontal parameters in patients in corrective orthodontic treatment.

Materials and methods

Twenty-eight patients were selected. Plaque index (PI), bleeding on probing (BOP), width of keratinized gingiva, levels of 40 bacterial species, and of 3 cytokines (IL-1β, MMP-8, and TNF-α) in gingival crevicular fluid (GCF) were evaluated at T0, before orthodontic treatment; T1, 6 months; and T2, 12 months post-treatment. Non-parametric, Friedman, Wilcoxon, ANOVA, and Spearman correlation coefficient tests were used for statistical analyses, with the significance level of 5%.

Results

No significant difference was found for the width of keratinized gingiva, but PI presented a significant increase at T1 and T2 (p < 0.05) when compared with T0. The percentage of sites with BOP increased significantly from T0 to T1 (p < 0.05); however, at T2, the values decreased and did not differ anymore from T0 (p > 0.05). In the microbiological analysis, red complex pathogens were in significantly greater proportions in T2 compared with T0 (p < 0.05). There was no statistically significant difference in the cytokine levels between the periods but there was a positive correlation between BOP and IL-1β (r = 0.49 p = .01) and TNF-α (r = 0.39 and p = .05).

Conclusion

In conclusion, corrective orthodontic treatment caused clinical periodontal alterations regarding biofilm accumulation and gingival bleeding, with alteration of periodontopathogens.

Is there a bidirectional association between rheumatoid arthritis and periodontitis? A systematic review and meta-analysis

BACKGROUND

Several lines of evidence suggest a bi-directional association between Rheumatoid Arthritis (RA) and Periodontitis (PD). Our aim was to systematically appraise the evidence on the association between RA and PD in terms of clinical and laboratory outcomes.

METHODS

An electronic search of several databases (PubMed, EMBASE, MEDLINE, LILACS, CINHL, Scopus, Web of Science, The Cochrane Library, OpenGrey and Google Scholar) was conducted up to March 2019 (PROSPERO CRD42018107817) by two independent reviewers. Observational studies included in the review were quality-appraised using the Newcastle-Ottawa Scale (NOS) tool. Random effects models were used for quantitative analyses.

RESULTS

A total of 8 case-control studies were identified after the final search of 1491 titles. Following quality assessment, 2 studies were excluded due to the high risk of bias, while the remaining 6 were further analysed. Meta-analyses revealed no substantial effect of RA on the Probing Pocket Depth (PPD) and Clinical Attachment Level (CAL) of patients with PD when compared to controls but high degree of study heterogeneity was found. To the contrary, PD was associated with substantially worse RA disease activity as assessed by an increase in the DAS28 score of 0.74 (0.25-1.24, 95%CI, p < 0.001).

CONCLUSION

There is consistent evidence suggesting that PD is associated with worse RA clinical activity as assessed by DAS28 scores whereas, RA patients do not have worsen PD clinical outcomes.

Chronodentistry: the role & potential of molecular clocks in oral medicine

Molecular clocks help organisms to adapt important physiological functions to periodically changing conditions in the environment. These include the adaption of the 24 h sleep-wake rhythm to changes of day and night. The circadian clock is known to act as a key regulator in processes of health and disease in different organs. The knowledge on the circadian clock led to the development of chronopharmacology and chronotherapy. These fields aim to investigate how efficiency of medication and therapies can be improved based on circadian clock mechanisms. In this review we aim to highlight the role of the circadian clock in oral tissues and its potential in the different fields of dentistry including oral and maxillofacial surgery, restorative dentistry, endodontics, periodontics and orthodontics to trigger the evolving field of chronodentistry.

The role of sclerostin and dickkopf-1 in oral tissues - A review from the perspective of the dental disciplines

Wnt signaling is of high relevance in the development, homeostasis, and regeneration of oral tissues. Therefore, Wnt signaling is considered to be a potential target for therapeutic strategies. The action of Wnt is tightly controlled by the inhibitors sclerostin (SOST) and Dickkopf (DKK)-1. Given the impact of SOST and DKK-1 in hard tissue formation, related diseases and healing, it is of high relevance to understand their role in oral tissues. The clinical relevance of this knowledge is further underlined by systemic and local approaches which are currently in development for treating a variety of diseases such as osteoporosis and inflammatory hard tissue resorption. In this narrative review, we summarize the current knowledge and understanding on the Wnt signaling inhibitors SOST and DKK-1, and their role in physiology, pathology, and regeneration in oral tissues. We present this role from the perspective of the different specialties in dentistry, including endodontics, orthodontics, periodontics, and oral surgery.

Orthodontic-periodontal interactions: Orthodontic extrusion in interdisciplinary regenerative treatments

Orthodontics is a periodontal treatment. "Guided orthodontic regeneration" (GOR) procedures use orthodontic movements in perio-restorative patients. The GOR technique includes a guided orthodontic "soft tissue" regeneration (GOTR) and a guided orthodontic "bone" regeneration (GOBR) with a plastic soft tissue approach and a regenerating reality. The increased amount of soft tissue gained with orthodontic movement can be used for subsequent periodontal regenerative techniques. The increased amount of bone can as well improve primary implant stability and, eventually, simplify a GTR technique to regenerate soft tissues, to restore tooth with external resorption in aesthetic zone or to extract a tooth to create new hard-soft tissue for adjacent teeth.

Biofunctionalization of porcine-derived collagen matrix using enamel matrix derivative and platelet-rich fibrin: influence on mature endothelial cell characteristics in vitro

OBJECTIVES

The present study evaluated the effect of an enamel matrix derivative (EMD) and platelet-rich fibrin (PRF)-modified porcine-derived collagen matrix (PDCM) on human umbilical vein endothelial cells (HUVEC) in vitro.

MATERIALS AND METHODS

PDCM (mucoderm®) was prepared to 6 mm (±0.1 mm) diameter discs. PDCM samples were incubated with either EMD, PRF, or control solutions for 100 min at 4 °C before the experiments. Cell-inducing properties of test materials on HUVEC cells were tested with cell proliferation assays (MTT, PrestoBlue®), a cytotoxicity assay (ToxiLight®), a Boyden chamber migration assay, and a cell attachment assay. Scanning electron microscopy (SEM) imaging was performed to determine the surface and the architecture of the modified matrices.

RESULTS

Cell proliferation was elevated in the EMD and PRF groups compared with control (p each ≤0.046). PRF modification increased HUVEC migration ability by 8-fold compared with both control and EMD groups (p each <0.001). Both treatments significantly promoted the cell attachment of HUVEC to PDCM, as assessed by direct cell counts on the matrices (p each <0.001).

CONCLUSIONS

HUVEC cell characteristics were overall improved by EMD- and PRF- modified PDCM. Adsorbed bioactive molecules to the PDCM surface may have contributed to a more preferable environment to surrounding cells.

CLINICAL RELEVANCE

The results may give evidence that PDCM modification with EMD or PRF, respectively, might be a useful approach to improve clinical outcomes, to prevent inflammatory reactions and wound-healing disturbances, and to expand the clinical application area of PDCM.

Additive Biomanufacturing: An Advanced Approach for Periodontal Tissue Regeneration

Periodontitis is defined as a chronic inflammatory condition, characterized by destruction of the periodontium, composed of hard (i.e. alveolar bone and cementum) and soft tissues (i.e. gingiva and periodontal ligament) surrounding and supporting the teeth. In severe cases, reduced periodontal support can lead to tooth loss, which requires tissue augmentation or procedures that initiate a repair, yet ideally a regenerative response. However, mimicking the three-dimensional complexity and functional integration of the different tissue components via scaffold- and/or matrix-based guided tissue engineering represents a great challenge. Additive biomanufacturing, a manufacturing method in which objects are designed and fabricated in a layer-by-layer manner, has allowed a paradigm shift in the current manufacturing of medical devices and implants. This shift from design-to-manufacture to manufacture-to-design, seen from a translational research point of view, provides the biomedical engineering and periodontology communities a technology with the potential to achieve tissue regeneration instead of repair. In this review, the focus is put on additively biomanufactured scaffolds for periodontal applications. Besides a general overview of the concept of additive biomanufacturing within this field, different developed scaffold designs are described. To conclude, future directions regarding advanced biomaterials and additive biomanufacturing technologies for applications in regenerative periodontology are highlighted.

Assessment of periodontal mechano-nociceptive function in healthy Chinese individuals

OBJECTIVE

Few clinical techniques are available for the description of mechano-nociceptive function in human periodontal tissues. The objective of this study was to test a new technique for assessment of periodontal mechano-nociceptive function by direct application of controlled forces to the teeth and quantify site, side and gender differences in healthy individuals.

DESIGN

Twenty healthy young adults (ten males and ten females) participated. A handheld pressure algometer was used to assess pressure pain threshold (PPT) on the maxillary and mandibular central incisors, canines and first premolars on the left and the right side from two directions: lateral and vertical. Statistical analysis was performed using analyses of variance (ANOVA) with repeated measures to compare data.

RESULTS

There were significant gender differences of PPT for both lateral (P_lateral=0.007) and vertical (P_vertical=0.001) directions with lower thresholds in females (higher sensitivity) than in males. A significant site effect (P_lateral=0.002, P_vertical<0.001) was observed with less sensitivity at the first premolar compared to the anterior teeth. No significant right-to-left side differences (P=0.082) were found for the PPTs. There were significant PPT differences between maxillary and mandibular teeth (P_lateral=0.020, P_vertical=0.041,) and significant differences between lateral and vertical direction (P<0.001).

CONCLUSION

The novel application of PPTs directly to the teeth indicated an adequate and practical method with potential value for clinical assessment of painful conditions affecting the periodontal ligament.

Effect of Bdellovibrio bacteriovorus HD100 on multispecies oral communities

The predation of Bdellovibrio bacteriovorus on different periodontal pathogens has already been described. However, it is necessary to consider the polymicrobial nature of periodontal disease. The current study explores the predation of Bdellovibrio on oral pathogens organized in multispecies communities. The effect of the predator was evaluated on in vitro six species communities with microbial culturing. Additionally, the effect on ex vivo subgingival plaque and saliva samples from periodontitis patients was assessed. In the latter experiment results were examined with microbial culturing, quantitative polymerase chain reaction (qPCR) and denaturing gradient gel electrophoresis (DGGE). The latter technique was used to get an overview of the whole mixed microbial population. Results showed that even in more complex models, B. bacteriovorus was still able to predate on Fusobacterium nucleatum and Aggregatibacter actinomycetemcomitans. However predation on Prevotella intermedia and Porphyromonas gingivalis could not be validated in multispecies models. The effect of Bdellovibrio was not restricted to the target bacteria. Changes in the overall ecology of the different models were evident. It could be concluded that the efficiency of predation decreased when complexity of the models increased. However, B. bacteriovorus was able to attack two important oral pathogens, F. nucleatum, and A. actinomycetemcomitans, even when present in ex vivo clinical samples. These effects still have to be validated in in vivo models to see the impact of Bdellovibrio on the whole bacterial ecology.

Use of cone beam computed tomography in periodontology

Diagnosis of periodontal disease mainly depends on clinical signs and symptoms. However, in the case of bone destruction, radiographs are valuable diagnostic tools as an adjunct to the clinical examination. Two dimensional periapical and panoramic radiographs are routinely used for diagnosing periodontal bone levels. In two dimensional imaging, evaluation of bone craters, lamina dura and periodontal bone level is limited by projection geometry and superpositions of adjacent anatomical structures. Those limitations of 2D radiographs can be eliminated by three-dimensional imaging techniques such as computed tomography. Cone beam computed tomography (CBCT) generates 3D volumetric images and is also commonly used in dentistry. All CBCT units provide axial, coronal and sagittal multi-planar reconstructed images without magnification. Also, panoramic images without distortion and magnification can be generated with curved planar reformation. CBCT displays 3D images that are necessary for the diagnosis of intra bony defects, furcation involvements and buccal/lingual bone destructions. CBCT applications provide obvious benefits in periodontics, however; it should be used only in correct indications considering the necessity and the potential hazards of the examination.

A chlorhexidine-loaded biodegradable cellulosic device for periodontal pockets treatment

Absorbent points widely used in endodontic therapy were transformed into bioresorbable chlorhexidine delivery systems for the treatment of the periodontal pocket by preventing its recolonization by the subgingival microflora. These paper points (PPs) were first oxidized to promote their resorption, then grafted with β-cyclodextrin (CD) or maltodextrin (MD) in order to achieve sustained delivery of chlorhexidine. We investigated the oxidation step parameters through the time of reaction and the nitric and phosphoric acid ratios in the oxidizing mixture, and then the dextrin grafting step parameters through the time and temperature of reaction. A first selection of the appropriate functionalization parameters was undertaken in relation to the degradation profile kinetics of the oxidized (PPO) and oxidized-grafted samples (PPO-CD and PPO-MD). Samples were then loaded with chlorhexidine digluconate (digCHX), a widely used antiseptic agent in periodontal therapy. The release kinetics of digCHX from PPO-CD and PPO-MD samples were compared to PP, PPO and to PerioChip(®) (a commercial digCHX containing gelatine chip) in phosphate buffered saline (pH 7.4) by ultraviolet spectrophotometry. The cytocompatibility of the oxidized-grafted PP was demonstrated by cell proliferation assays. Finally, the disc diffusion test from digCHX loaded PPO-MD samples immersed in human plasma was developed on pre-inoculated agar plates with four common periodontal pathogenic strains: Fusobacterium nucleatum, Prevotella melaninogenica, Aggregatibacter actinomycetem comitans and Porphyromonas gingivalis. To conclude, the optimized oxidized-dextrin-grafted PPs responded to our initial specifications in terms of resorption and digCHX release rates and therefore could be adopted as a reliable complementary periodontal therapy.