Luca Levrini

Peripheral Mechanisms of Dental Pain: The Role of Substance P

Current evidence supports the central role of neuropeptides in the molecular mechanisms underlying dental pain. In particular, substance P, a neuropeptide produced in neuron cell bodies localised in dorsal root and trigeminal ganglia, contributes to the transmission and maintenance of noxious stimuli and inflammatory processes. The major role of substance P in the onset of dental pain and inflammation is increasingly being recognised. Well-grounded experimental and clinical observations have documented an increase in substance P concentration in patients affected by caries, pulpitis, or granulomas and in those undergoing standard orthodontic or orthodontic/dental care procedures. This paper focuses on the role of substance P in the induction and maintenance of inflammation and dental pain, in order to define future lines of research for the evaluation of therapeutic strategies aimed at modulating the complex effects of this mediator in oral tissues.

Immediate loading of mandibular overdentures supported by one-piece, direct metal laser sintering mini-implants: a short-term prospective clinical study.

BACKGROUND Only a few studies have dealt with immediately loaded, unsplinted mini-implants supporting ball attachment-retained mandibular overdentures (ODs). The aim of this study is to evaluate treatment outcomes of ball attachment-retained mandibular ODs supported by one-piece, unsplinted, immediately loaded, direct metal laser sintering (DMLS) mini-implants. METHODS Over a 4-year period (2009 to 2012), all patients referred to the Dental Clinic, University of Varese, and to a private practice for treatment with mandibular ODs were considered for inclusion in this study. Each patient received three or four DMLS mini-implants. Immediately after implant placement, a mandibular OD was connected to the implants. At each annual follow-up session, clinical and radiographic parameters were assessed, including the following outcome measures: 1) implant failures; 2) peri-implant marginal bone loss; and 3) complications. Statistical analysis was conducted using a life-table analysis. RESULTS A total of 231 one-piece DMLS mini-implants were inserted in 62 patients. After 4 years of loading, six implants failed, giving an overall cumulative survival rate of 96.9%. The mean distance between the implant shoulder and the first visible bone-to-implant contact was 0.38 ± 0.25 and 0.62 ± 0.20 mm at the 1- and 4-year follow-up examinations, respectively. An incidence of 6.0% of biologic complications was reported; prosthetic complications were more frequent (12.9%). CONCLUSIONS Within the limits of this study, it can be concluded that the immediate loading of one-piece, unsplinted, DMLS titanium mini-implants by means of ball attachment-supported mandibular ODs is a successful treatment procedure. Long-term follow-up studies are needed to confirm these results.

Esthetic Evaluation of Implants Placed after Orthodontic Treatment in Patients with Congenitally Missing Lateral Incisors

OBJECTIVE The aim of this retrospective study was to evaluate the esthetic outcome of single tooth Morse taper connection implants used to replace congenitally missing lateral incisors after orthodontic treatment by means of the pink esthetic score (PES) and white esthetic score (WES) index. MATERIALS AND METHODS Twenty consecutive patients who were treated with a single tooth Morse taper connection implants (Leone Implant System®, Florence, Italy) were enrolled in this study. An independent calibrated examiner applied the PES/WES index to 20 implant-supported restorations 3 months and 3 years after implant placement. RESULTS No implants were lost. All 20 implants fulfilled the established success criteria for dental implants with regard to osseointegration and prosthetic complications, with an overall implant-crown success of 100.0%. At the 3 year examination, the mean distance between the implant shoulder and the first visible bone-implant contact was of 0.49 ± 0.18 mm (95% confidence interval 0.41-0.57); the mean PES was 8.15 ± 1.69, and the mean WES was 8.70 ± 0.92. CONCLUSIONS The placement of single-tooth Morse taper connection implants for rehabilitation of congenitally missing lateral incisors after orthodontic treatment represents a successful procedure in the medium term. Further studies are necessary in order to assess the long-term esthetic score. CLINICAL SIGNIFICANCE This paper evaluates the esthetic outcome of Morse taper connection implants placed to restore congenitally missing lateral incisors after orthodontic treatment.

Ultramorphology of the root surface subsequent to hand-ultrasonic simultaneous instrumentation during non-surgical periodontal treatments. An in vitro study

Objective The purpose of this study was to investigate the ultramorphology of the root surfaces induced by mechanical instrumentation performed using conventional curettes or piezoelectric scalers when used single-handedly or with a combined technique. Material and Methods Thirty single-rooted teeth were selected and divided into 3 groups: Group A, instrumentation with curettes; Group B instrumentation with titanium nitride coated periodontal tip mounted in a piezoelectric handpiece; Group C, combined technique with curette/ultrasonic piezoelectric instrumentation. The specimens were processed and analyzed using confocal and scanning electron microscopy. Differences between the different groups of instrumentation were determined using Pearson’s χ 2 with significance predetermined at α=0.001. Results Periodontal scaling and root planing performed with curettes, ultrasonic or combined instrumentation induced several morphological changes on the root surface. The curettes produced a compact and thick multilayered smear layer, while the morphology of the root surfaces after ultrasonic scaler treatment appeared irregular with few grooves and a thin smear layer. The combination of curette/ultrasonic instrumentation showed exposed root dentin tubules with a surface morphology characterized by the presence of very few grooves and slender remnants of smear layer which only partially covered the root dentin. In some cases, it was also possible to observe areas with exposed collagen fibrils. Conclusion The curette-ultrasonic simultaneous instrumentation may combine the beneficial effects of each instrument in a single technique creating a root surface relatively free from the physical barrier of smear layer and dentin tubules orifices partial occlusion.

Oral Signs and HLA-DQB1*02 Haplotypes in the Celiac Paediatric Patient: A Preliminary Study

Celiac disease (CD) diagnosis can be extremely challenging in the case of atypical patterns. In this context, oral signs seem to play a decisive role in arousing suspicion of these forms of the disease. At the same time, the different expressions of the HLA-DQB1∗02 allele apparently seem to facilitate the interpretation of signs and highlighted symptoms. The aim of this work was to verify whether it is possible to identify a correlation between the development of oral signs and different DQ2 haplotypes in celiac pediatric patients. 44 celiac patients with a medium age of 9.9 were studied. Oral examinations were performed in order to identify recurrent aphthous stomatitis (RAS) and dental enamel defects (DED). The diagnosis of DED resulted as being related to allele expression (P value = 0.042) while it was impossible to find a similar correlation with RAS. When both oral signs were considered, there was an increase in correlation with HLA-DQB1∗02 expression (P value = 0.018). The obtained results identified both the fundamental role that dentists can play in early diagnosis of CD, as well as the possible role of HLA haplotype analysis in arousing suspicion of atypical forms of the disease.

Periodontal health status in patients treated with the Invisalign ® system and fixed orthodontic appliances: A 3 months clinical and microbiological evaluation

Objective: The aim of this prospective study was to compare the periodontal health and the microbiological changes via real-time polymerase chain reaction (PCR) in patients treated with fixed orthodontic appliances and Invisalign® system (Align Technology, Santa Clara, California). Materials and Methods: Seventy-seven patients were enrolled in this study and divided into three groups (Invisalign® group, fixed orthodontic appliances group and control group). Plaque index, probing depth, bleeding on probing were assessed. Total biofilm mass and periodontal pathogens were analyzed and detected via real-time PCR. All these data were analyzed at the T0 (beginning of the treatment) T1 (1-month) and T2 (3 months); and statistically compared using the Mann–Whitney test for independent groups. Results: After 1-month and after 3 months of treatment there was only one sample with periodontopathic anaerobes found in patient treated using fixed orthodontic appliances. The Invisalign® group showed better results in terms of periodontal health and total biofilm mass compared to the fixed orthodontic appliance group. A statistical significant difference (P < 0.05) at the T2 in the total biofilm mass was found between the two groups. Conclusion: Patients undergoing orthodontic treatment with the Invisalign® System show a superior periodontal health in the short-term when compared to patients in treatment with fixed orthodontic appliances. Invisalign® should be considered as afirst treatment option in patients with risk of developing periodontal disease.

Changes of Substance P in the Crevicular Fluid in relation to Orthodontic Movement Preliminary Investigation

Substance P (SP) is a tachykinin released from both the central and the peripheral endings of primary afferent neurons and functions as a neurotransmitter. As a transmitter signaling pain, substance P is involved in nociception and is an extremely potent vasodilator. We found several studies about this neuropeptide especially in relation to parodontology and a few orthodontic reviews. This is because in the past the importance of this neuropeptide in dental element undergoing periodontal inflammation was observed. The aims of the present pilot study was to investigate whether the substance P was present in gingival crevicular fluid in dental elements undergoing orthodontic treatment with Invisalign technique compared to teeth belonging to the same series but not undergoing orthodontic movement. We analysed gengival crevicular fluid (GCF) collected from four young subjects, using a paper cone for a time of 60 seconds. The results showed that SP is present in the gengival sulcus in elements undergoing orthodontic forces during treatment with Invisalign technique and not in the control teeth. During the literature analysis, we have found a lot of papers describing involvement of SP in periodontitis and inflammatory diseases, but further studies are needed in order to demonstrate the role of this neuropeptide during teeth movement.

Dental Wear: A Scanning Electron Microscope Study

Dental wear can be differentiated into different types on the basis of morphological and etiological factors. The present research was carried out on twelve extracted human teeth with dental wear (three teeth showing each type of wear: erosion, attrition, abrasion, and abfraction) studied by scanning electron microscopy (SEM). The study aimed, through analysis of the macro- and micromorphological features of the lesions (considering the enamel, dentin, enamel prisms, dentinal tubules, and pulp), to clarify the different clinical and diagnostic presentations of dental wear and their possible significance. Our results, which confirm current knowledge, provide a complete overview of the distinctive morphology of each lesion type. It is important to identify the type of dental wear lesion in order to recognize the contributing etiological factors and, consequently, identify other more complex, nondental disorders (such as gastroesophageal reflux, eating disorders). It is clear that each type of lesion has a specific morphology and mechanism, and further clinical studies are needed to clarify the etiological processes, particularly those underlying the onset of abfraction.

Scanning electron microscopy analysis of the growth of dental plaque on the surfaces of removable orthodontic aligners after the use of different cleaning methods.

Background Advances in orthodontics are leading to the use of minimally invasive technologies, such as transparent removable aligners, and are able to meet high demands in terms of performance and esthetics. However, the most correct method of cleaning these appliances, in order to minimize the effects of microbial colonization, remains to be determined. Purpose The aim of the present study was to identify the most effective method of cleaning removable orthodontic aligners, analyzing the growth of dental plaque as observed under scanning electron microscopy. Methods Twelve subjects were selected for the study. All were free from caries and periodontal disease and were candidates for orthodontic therapy with invisible orthodontic aligners. The trial had a duration of 6 weeks, divided into three 2-week stages, during which three sets of aligners were used. In each stage, the subjects were asked to use a different method of cleaning their aligners: 1) running water (control condition); 2) effervescent tablets containing sodium carbonate and sulfate crystals followed by brushing with a toothbrush; and 3) brushing alone (with a toothbrush and toothpaste). At the end of each 2-week stage, the surfaces of the aligners were analyzed under scanning electron microscopy. Results The best results were obtained with brushing combined with the use of sodium carbonate and sulfate crystals; brushing alone gave slightly inferior results. Conclusion On the basis of previous literature results relating to devices in resin, studies evaluating the reliability of domestic ultrasonic baths for domestic use should be encouraged. At present, pending the availability of experimental evidence, it can be suggested that dental hygienists should strongly advise patients wearing orthodontic aligners to clean them using a combination of brushing and commercially available tablets for cleaning oral appliances.

Experimentally Induced Pulpal Lesion and Substance P Expression: Effect of Ketoprofen—A Preliminary Study

Objectives. To evaluate substance P (SP) and the effect of ketoprofen administration, a nonsteroidal anti-inflammatory drug (NSAID), on SP in the pulp of upper third molars with experimentally induced pulpal lesion. Materials and Methods. A sample of 20 young systemically healthy adults of both sexes, nonsmokers, with a healthy upper third molar to extract for orthodontic purposes, was selected. Prior to the procedure, an inflammatory process was generated by mechanical exposure of the pulp. After 15 minutes, the pulp was collected using a sterile barbed broach. SP levels were determined by using a commercially available enzyme immunoassay (ELISA) kit. The subjects were randomly divided into two groups: group 1 received a dose of ketoprofen 30 minutes prior to the experimental procedure. The subjects of group 2 did not receive any kind of drug administration. The patients were asked to complete a diary on the postoperative pain. Results. No statistically significant difference could be detected in SP expression between the two groups. In group 1, pain manifestation was significantly delayed in comparison with group 2. Conclusions. Preventive administration of ketoprofen did not significantly affect the pulpal levels of SP but resulted in a significantly postponed manifestation of pain after extraction.