A Systematic Review of Oral Modifications Caused by the Prolonged Application of Continuous Positive Airway Pressure (CPAP) and Intraoral Appliances in Patients with Obstructive Sleep Apnea (OSA).

Objective: Prolonged use of oral devices as a substitute for traditional treatments has been studied in relation to the dental and skeletal changes associated with obstructive sleep apnea syndrome (OSA), which is a sleep-breathing disorder. Materials and Methods: A review of articles indexed in PubMed, Google Scholar, Cochrane Library, Scopus, Web of Sciences, and CINHAL databases in September 2022 based on MeSH-based keywords with "dental and skeletal" and "oral appliance" and "obstructive sleep apnea" was examined to ensure that the keywords alone or cross-linked, depending on which base of the searched data, were used. 16 articles out of 289 articles were included in the research, and 273 articles were excluded due to lack of study. Conclusions: CPAP treatment has limited dental or skeletal effects in short-term or long-term use. OAs and MADs show significant dental changes with prolonged use. MAS and TSD are more effective in short-term goals than CPAP. OAs' increase may cause dental and skeletal changes. MPD shows notable cephalometric alterations.

Oral findings in pediatric patients with allergic rhinitis and asthma: a cohort study of an Italian setting.

Allergic rhinitis and asthma are two frequent respiratory clinical entities commonly encountered in pediatric clinical settings. Previous studies have evaluated the influence of these two conditions on oral health, but conflicting results have been obtained. The present cohort study aimed to record oral findings (i.e., caries, plaque, gingival inflammation and mouth breathing) in 50 pediatric patients diagnosed with allergic rhinitis and/or asthma in an Italian pediatric setting and to compare them to a control group of 50 healthy children. The following oral indexes were calculated: Periodontal Screening and Recording (PSR), Plaque Control Record (PCR), and Decayed Missing Filled Teeth (DMFT) Index. The absence or presence of mouth breathing was also recorded. Descriptive and inferential statistics were conducted. Statistically significant differences were found between cases and controls for PSR (p = 0.0051) and PCR scores (p < 0.0001), whereas no significant differences were detected for DMFT. Mouth breathing was found among 20 (40.00%) patients of the Case Group, while in the Control group only in 11 (22.00%) patients, and no significant differences were found between allergic rhinitis and asthma gradings for mouth breathers (p > 0.05). Finally, linear regressions showed a significant influence of PSR (p = 0.0051) and PCR (p < 0.0001) on the Case group. Mouth breathing also significantly influenced PCR scores of the Case group (p = 0.0206). Accordingly, allergic rhinitis and asthma can promote mouth breathing, plaque accumulation, and periodontal inflammation. Based on these considerations, pediatric dentists and physicians are expected to know the influence of respiratory conditions on oral health and consider this aspect when taking care of children.

The Use of Questionnaires in Pain Assessment during Orthodontic Treatments: A Narrative Review.

Pain is a complex multidimensional feeling combined with sensorial and emotional features. The majority of patients undergoing orthodontic treatment report various degrees of pain, which is perceived as widely variable between individuals, even when the stimulus is the same. Orthodontic pain is considered the main cause of poor-quality outcomes, patients' dissatisfaction, and lack of collaboration up to the interruption of therapy. A deep understanding of pain and how it influences a patient's daily life is fundamental to establishing proper therapeutic procedures and obtaining the correct collaboration. Because of its multifaced and subjective nature, pain is a difficult dimension to measure. The use of questionnaires and their relative rating scales is actually considered the gold standard for pain assessment. Choosing the most appropriate instrument for recording self-reported pain depends on a patient's age and cognitive abilities. Although several such scales have been proposed, and a lot of them are applied, it remains uncertain which of these tools represents the standard and performs the most precise, universal, and predictable task. This review aims to give an overview of the aspects which describe pain, specifically the pain experienced during orthodontic treatment, the main tool to assess self-perceived pain in a better and more efficient way, the different indications for each of them, and their correlated advantages or disadvantages.

Mechanisms of initiation of cortical spreading depression.

BACKGROUND: There is increasing evidence from human and animal studies that cortical spreading depression (CSD) is the neurophysiological correlate of migraine aura and a trigger of migraine pain mechanisms. The mechanisms of initiation of CSD in the brain of migraineurs remain unknown, and the mechanisms of initiation of experimentally induced CSD in normally metabolizing brain tissue remain incompletely understood and controversial. Here, we investigated the mechanisms of CSD initiation by focal application of KCl in mouse cerebral cortex slices. METHODS: High KCl puffs of increasing duration up to the threshold duration eliciting a CSD were applied on layer 2/3 whilst the membrane potential of a pyramidal neuron located very close to the site of KCl application and the intrinsic optic signal were simultaneously recorded. This was done before and after the application of a specific blocker of either NMDA or AMPA glutamate receptors (NMDARs, AMPARs) or voltage-gated Ca2+ (CaV) channels. If the drug blocked CSD, stimuli up to 12-15 times the threshold were applied. RESULTS: Blocking either NMDARs with MK-801 or CaV channels with Ni2+ completely inhibited CSD initiation by both CSD threshold and largely suprathreshold KCl stimuli. Inhibiting AMPARs with NBQX was without effect on the CSD threshold and velocity. Analysis of the CSD subthreshold and threshold neuronal depolarizations in control conditions and in the presence of MK-801 or Ni2+ revealed that the mechanism underlying ignition of CSD by a threshold stimulus (and not by a just subthreshold stimulus) is the CaV-dependent activation of a threshold level of NMDARs (and/or of channels whose opening depends on the latter). The delay of several seconds with which this occurs underlies the delay of CSD initiation relative to the rapid neuronal depolarization produced by KCl. CONCLUSIONS: Both NMDARs and CaV channels are necessary for CSD initiation, which is not determined by the extracellular K+ or neuronal depolarization levels per se, but requires the CaV-dependent activation of a threshold level of NMDARs. This occurs with a delay of several seconds relative to the rapid depolarization produced by the KCl stimulus. Our data give insights into potential mechanisms of CSD initiation in migraine.

Local anesthesia with SleeperOne S4 computerized device vs traditional syringe and perceived pain in pediatric patients: a randomized clinical trial.

Local anesthesia is performed in dentistry before clinical procedures to avoid pain. Children can show fear at the sight of the needle and pain at its insertion. To make local anesthesia more comfortable, the use of computer-controlled local anesthetic delivery (CCLAD) systems has been developed to control the flow rate of the anesthetic solution injected through the needle. The aim of the present research is to evaluate and compare the discomfort felt by patients using a traditional syringe and the CCLAD system SleeperOne®, by considering pain, size sensation, bitterness, and vomit. 30 patients were included in the study and randomly assigned to traditional anesthesia or CCLAD. After injection, patients were assessed for the abovementioned outcomes. A Visual Analogue Scale (VAS) from 0 to 10 scores was used. As far as pain is concerned, statistically lower mean values were found in the Trial group (p < 0.05). Instead, concerning size, bitterness and vomit perceptions, no statistically significant differences were found between the groups (p > 0.05). Linear regressions were calculated considering technique, quadrant, dental arch, tooth, dentition, sex, and age as independent variables. The technique has shown to have a significant influence on pain (p < 0.05), with lower values for SleeperOne® device. Pain resulted significantly influenced by the type of dentition (p < 0.05), with higher scores for deciduous one. Moreover, perceived pain decreased with the increase of the age of patients (p < 0.05). At last, bitterness perception scores resulted to be higher for primary first molars (p < 0.05). SleeperOne® device seems to be a valid support for the reduction of pain related to anesthetic injection, especially in children. Further studies should evaluate CCLADs' uses combined with lidocaine preanesthetic as well as with conscious sedation through nitrous oxide in order to determine possible synergistic effects between these procedures.

Adult hippocampal neurogenesis and social behavioural deficits in the R451C Neuroligin3 mouse model of autism are reverted by the antidepressant fluoxetine.

Neuron generation persists throughout life in the hippocampus but is altered in animal models of neurological and neuropsychiatric diseases, suggesting that disease-associated decline in cognitive and emotional hippocampal-dependent behaviours might be functionally linked with dysregulation of postnatal neurogenesis. Depletion of the adult neural stem/progenitor cell (NSPCs) pool and neurogenic decline have been recently described in mice expressing synaptic susceptibility genes associated with autism spectrum disorder (ASDs). To gain further insight into mechanisms regulating neurogenesis in mice carrying mutations in synaptic genes related to monogenic ASDs, we used the R451C Neuroligin3 knock-in (Nlgn3 KI) mouse, which is characterized by structural brain abnormalities, deficits in synaptic functions and reduced sociability. We show that the number of adult-born neurons, but not the size of the NSPC pool, was reduced in the ventral dentate gyrus in knock-in mice. Notably, this neurogenic decline was rescued by daily injecting mice with 10 mg/Kg of the antidepressant fluoxetine for 20 consecutive days. Sustained treatment also improved KI mice's sociability and increased the number of c-Fos active adult-born neurons, compared with vehicle-injected KI mice. Our study uncovers neurogenesis-mediated alterations in the brain of R451C KI mouse, showing that the R451C Nlgn3 mutation leads to lasting, albeit pharmacologically reversible, changes in the brain, affecting neuron formation in the adult hippocampus. Our results suggest that fluoxetine can ameliorate social behaviour in KI mice, at least in part, by rescuing adult hippocampal neurogenesis, which may be relevant for the pharmacological treatment of ASDs.

Impacted Palatal Canines and Diode Laser Surgery: A Case Report.

Introduction: Maxillary canine is the most frequent dental element that could likely remain impacted in the bone structure, with a percentage between 1 and 5%. This study presents a case report using a diode laser for surgical-orthodontics disinclusion of a palatal mucosal impacted permanent left upper canine (2.3) and the simultaneous application of an orthodontic bracket. Methods: After cementation of the trans-palatal bar to the upper first molars with a hook for orthodontic traction, local anaesthesia with articaine was performed, followed by surgical operculectomy using a diode laser (810 nm wavelength, continuous wave mode with a power output of 3 W, and a 0.4 mm diameter optical fiber), and the orthodontic bracket with a passive metal looped ligature was applied. Subsequently, active elastic traction was applied on 2.3 and the upper arch was bonded for the application of a series of orthodontic wires, lace-back, and metal ligatures. A progressive reactivation of the elastic traction and extraction of 6.3 was necessary to translate the canine into the correct arch position. Results: Diode laser surgical-orthodontic disinclusion of impacted upper canine was performed successively, resulting in a dry surgical field ideal for orthodontic bracket adhesion. No pain and no swelling have been reported from the patient. The orthodontic treatment allowed the canine to be moved to the correct position in the arch. Conclusions: This case showed that the diode laser is a valid alternative for the surgical-orthodontic disinclusion of an included tooth element.

Specific activation of GluN1-N2B NMDA receptors underlies facilitation of cortical spreading depression in a genetic mouse model of migraine with reduced astrocytic glutamate clearance.

Migraine is a common but poorly understood sensory circuit disorder. Mouse models of familial hemiplegic migraine (FHM, a rare monogenic form of migraine with aura) show increased susceptibility to cortical spreading depression (CSD, the phenomenon that underlies migraine aura and can activate migraine headache mechanisms), allowing an opportunity to investigate the mechanisms of CSD and migraine onset. In FHM type 2 (FHM2) knock-in mice with reduced expression of astrocytic Na+, K+-ATPases, the reduced rate of glutamate uptake into astrocytes can account for the facilitation of CSD initiation. Here, we investigated the underlying mechanisms and show that the reduced rate of glutamate clearance in FHM2 mice results in increased amplitude and slowing of rise time and decay of the NMDA receptor (NMDAR) excitatory postsynaptic current (EPSC) elicited in layer 2/3 pyramidal cells by stimulation of neuronal afferents in somatosensory cortex slices. The relative increase in NMDAR activation in FHM2 mice is activity-dependent, being larger after high-frequency compared to low-frequency afferent activity. Inhibition of GluN1-N2B NMDARs, which hardly affected the NMDAR EPSC in wild-type mice, rescued the increased and prolonged activation of NMDARs as well as the facilitation of CSD induction and propagation in FHM2 mice. Our data suggest that the enhanced susceptibility to CSD in FHM2 is mainly due to specific activation of extrasynaptic GluN1-N2B NMDARs and point to these receptors as possible therapeutic targets for prevention of CSD and migraine.

Photobiomodulation and Pain Reduction in Patients Requiring Orthodontic Band Application: Randomized Clinical Trial.

PURPOSE: The aim of this study was to investigate the effect of Photobiomodulation (PBM) in managing orthodontic pain intensity over time in patients requiring band application on upper first molars. METHODS: Maxillary first molars were banded. In the trial group, each molar received single-session PBM on two buccal and two palatal points (λ = 830 ± 10 nm; 150 mW, 7.5 J/cm2; spot of 0.1 cm2; 5 sec per point), while the control group received a placebo treatment. All patients were asked to answer five pain rating scales to assess pain intensity at 5 minutes and 1, 12, 24, and 72 hours and completed a survey describing the type of pain and its temporal course in the next 7 days. RESULTS: 26 patients (mean age 11.8 years) were randomly assigned to a control or a trial group. The trial group showed significantly lower pain intensities (p < 0.05) at 5 min (M = 0.92, SD = 1.32), 1 h (M = 0.77, SD = 1.01), and 12 h (M = 0.77, SD = 1.54) after band application compared to the control group (5 min: M = 1.62, SD = 1.26; 1 h: M = 1.77, SD = 1.92; and 12 h: M = 1.77, SD = 2.17), whereas no difference between groups (p > 0.05) was found at 24 h (trial: M = 0.62, SD = 1.71; control: M = 1.08, SD = 1.75) and 72 h (trial: M = 0.31, SD = 0.75; control: M = 0.15, SD = 0.55). Patients in the control group reported more frequently the presence of "compressive pain" (58.8%, p < 0.05) from the appliance during the week after the application, while the trial group showed higher frequency of "no pain" (46.2%, p < 0.05). However, PBM did not affect the pain onset (trial: M = 10.86, SD = 26.97; control: M = 5.25, SD = 7.86), peak (trial: M = 15.86, SD = 26.29; control: 6.17, SD = 7.96), and end time (trial: 39.57, SD = 31.33; control: M = 22.02, SD = 25.42) reported by the two groups (p > 0.05). CONCLUSIONS: PBM might be considered a promising alternative to decrease general pain intensity, although not affecting the typical pain cycle, in terms of the onset, peak, and ending times.

Digital Workflow for Indirect Bonding with 2D Lingual Brackets: A Case Report and Procedure Description.

OBJECTIVE: During orthodontic therapy, accuracy in bonding procedures makes it easier to correct tooth alignment by decreasing the need for midcourse corrections by changing bracket positions. Indirect bonding allows the transfer of the appliance components from model casts to patient's teeth potentially meaning shorter appointments for bracket bonding and rebonding and best comfort during chairside practice. At the same time, there has been a steady increase in requests for invisible lingual orthodontic treatment. CLINICAL CONSIDERATIONS: Accordingly, the aim of the present report is to illustrate the workflow to realize a complete digital indirect bonding for lingual brackets (2D, Forestadent). The procedure starts with intraoral digital scans, digital 3D model, and virtual bracket positioning, ending with the realization of a CAD-CAM prototyped transfer tray. A 3D intraoral scanner (True Definition, 3M) is used to create digital scans and digital models. A virtual bracket positioning is performed using software (NemoCast, Dentaurum), and a prototyped transfer tray is created by a CAD-CAM device. 2D lingual brackets were positioned inside the tray, so the appliance was bonded to the dental surface using light curing adhesive resin. CONCLUSIONS: During orthodontic treatment, CAD/CAM technology could help clinicians. Computer-constructed transfer trays can reduce clinician error and improve the everyday workflow in the office.

Diode Laser-Assisted Surgical Therapy for Early Treatment of Oral Mucocele in a Newborn Patient: Case Report and Procedures Checklist.

Mucocele (also known as ranula or salivary gland mucous cyst) of the newborn is a lesion present on the intraoral cavity, with the potential to interfere with respiration and feeding. In the present report, a case of mucocele in a 4-month female patient has been described. As conventional surgery can be followed by several complications such as intraoperative bleeding, difficulties in wound healing, and maintenance of sterility during surgery, in the present case, the use of diode laser has been planned. A topic anesthesia with lidocaine gel was performed. A diode laser (810 nm wavelength, continuous wave mode, power output of 3 watt, and 0.4 mm diameter fiber optic) was set for excising the lesion. The tip was directed at an angle of 10 to 15°, moving around the base of the lesion with a circular motion. The procedure was completed in 3 minutes. The patient was visited with a follow-up of 2 weeks and 4 months after excision. The intraoral wound healed without complications, and no signs of infection or mass recurrence were noted. The histopathological examination confirmed the diagnosis of mucocele. On the basis of the results of the present case report, the use of diode laser can be easily performed also in a noncompliant newborn patient for successful excision of mucocele lesions, and checklist of clinical procedures has been described.

Multicenter randomized, double-blind controlled trial to evaluate the efficacy of laser therapy for the treatment of severe oral mucositis induced by chemotherapy in children: laMPO RCT.

OBJECTIVES: To demonstrate the efficacy of laser photobiomodulation (PBM) compared to that of placebo on severe oral mucositis (OM) in pediatric oncology patients. The primary objective was the reduction of OM grade (World Health Organization [WHO] scale) 7 days after starting PBM. Secondary objectives were reduction of pain, analgesic consumption, and incidence of side effects. METHODS: One hundred and one children with WHO grade > 2 chemotherapy-induced OM were enrolled in eight Italian hospitals. Patients were randomized to either PBM or sham treatment for four consecutive days (days +1 to +4). On days +4, +7, and +11, OM grade, pain (following a 0-10 numeric pain rating scale, NRS) and need for analgesics were evaluated by an operator blinded to treatment. RESULTS: Fifty-one patients were allocated to the PBM group, and 50 were allocated to the sham group. In total, 93.7% of PBM patients and 72% of sham patients had OM grade < 3 WHO on day +7 (P = 0.01). A significant reduction of pain was registered on day +7 in the PBM versus sham group (NRS 1 [0-3] vs. 2.5 [1-5], P < 0.006). Reduced use of analgesics was reported in the PBM group, although it was not statistically significant. No significant adverse events attributable to treatment were recorded. CONCLUSIONS: PBM is a safe, feasible, and effective treatment for children affected by chemotherapy-induced OM, as it accelerates mucosal recovery and reduces pain.

Preliminary study in a new protocol for the treatment of oral mucositis in pediatric patients undergoing hematopoietic stem cell transplantation (HSCT) and chemotherapy (CT).

Oral mucositis (OM) is a debilitating and serious side effect in patients undergoing hematopoietic stem cell transplantation (HSCT) and chemotherapy (CT). Laser therapy is becoming a promising treatment option in these patients, avoiding the necessity of enteral/parenteral nutrition. The aim of this study was to evaluate the efficacy of laser therapy in patients affected by oral mucositis induced by chemotherapy and HSCT. Sixteen onco-hematological pediatric patients receiving chemotherapy and hematopoietic stem cell transplantation, affected by oral mucositis, were enrolled in this study. They were divided in two randomized groups: the laser group and the placebo-control group. Patients in the laser group were treated with HPLT (970 ± 15 nm, 3.2 W (50%), 35-6000 Hz, 240 s) for four consecutive days, once a day; and placebo group underwent sham treatment. The assessment of mucositis was recorded through WHO Oral Mucositis Grading Objective Scale, and pain was evaluated through Visual Analogue Scale (VAS). Patients were monitored and evaluated 3, 7, and 11 days after the first day of laser therapy. Once OM was diagnosed, the patients had mucositis grading assessments before laser or sham application at day 3, 7, and 11 after first application. All patients of laser group demonstrated improvement in pain sensation from day 3 after first application of laser (p < 0.05), ulcerations reduced their dimensions and erythema disappeared. The patients of placebo group had improvement from day 7. In laser group, all mucositis were fully resolved from day 7 (p < 0.05). Oral mucositis negatively impacts on nutritional intake, oral hygiene, and quality of life. Laser therapy appears to be a safe and innovative approach in the management of oral mucositis. In this preliminary study, HPLT encourages to consider laser therapy as a part of onco-hematological protocol, providing to decrease pain and duration of OM induced by CT and HSCT. Further researches will be needed, especially randomized, controlled clinical trials with a large number of enrolled patients and a long term of follow-up to confirm the efficacy of laser therapy in prevention and control of OM in onco-hematological pediatric patients.

[Epidemiological study of dental and facial asymmetries in a sample of preschool subjects]. / Studio epidemiologico delle asimmetrie facciali e dentali in un campione di soggetti in età prescolare.

OBJECTIVES: to identify the typologies of facial and dental asymmetries in a sample of children aged between 3 and 6 years and to correlate these asymmetries with possible morphological and functional situations. DESIGN: cross-sectional observational study. SETTING AND PARTICIPANTS: sample of 95 subjects aged between 3 and 6 years. Clinical data were collected in 10 sessions conducted during school hours in April 2013 by a doctor of Dentistry at two preschools in the city of Sanremo (Liguria Region, Northern Italy) and a kindergarten in the city of Pavia (Lombardy Region, Northern Italy). To collect the data, a weighted clinical questionnaire was used. MAIN OUTCOME MEASURES: presence and type of bad habit, type of breathing, presence and type of facial asymmetry, dental formula, presence of diastema, presence and type of occlusal asymmetries, presence and type of dental malocclusions. RESULTS: analysed sample consisted of 53.7% (51/95) of males and 46.3 % (44/95) females; the mean age was 4.3 ± 0.9 years. Most frequent facial asymmetry is orbits asymmetry (35%, 33/95); dental malocclusions are detected in 70%(67/95) of cases. High percentage of subjects (69.5%, 66/95) presents displacement between superior dental midline (SDM) and inferior dental midline (IDM). Several statistically significant associations are observed: in particular, asymmetry of molar ratios is linked to asymmetry of the cheekbones and displacement of the SDM; facial midline has statistical association with asymmetry of the cheekbones (p <0.001). CONCLUSIONS: the results of this study agree with scientific literature, in particular as regards the prevalence of compromising habits observed and the close correlation between: the presence of dental malocclusions and the presence of compromising habits, the presence of dental malocclusions and the presence of oral breathing.

Laser light may improve the symptoms of oral lesions of cicatricial pemphigoid: a case report.

OBJECTIVE: The aim of this work is to report the handling of a patient suffering from cicatricial pemphigoid (CP) treated with laser phototherapy (LPT) and systemic steroids. BACKGROUND DATA: CP is a group of rare chronic autoimmune blistering diseases that predominately affect the mucous membranes and occasionally the skin. The gingiva is most commonly involved, followed by the palate and the buccal mucosa. High-dosage systemic steroids are widely used for its treatment. LPT has been shown to improve wound healing and relieve pain. Its efficacy depends on the amount of energy delivered to the tissue, exposure time, and delivery method. MATERIALS AND METHODS: A white 47-y-old man with CP who used systemic steroids for the previous 5 y was examined at our clinic. Extra- and intraoral examination revealed classic signs of the condition. LPT (GaAlAs diode laser, 660 nm wavelength, 30 mW, continuous wave, diameter approximately 3 mm, 60 J/cm(2) per session) was used in association with the steroids. LPT was performed in a punctual contact manner every other day on the oral mucosa. Maintenance of the treatment was carried out weekly because interruption of the LPT resulted in the recurrence of the lesions. At the time that this report was written, the patient had been undergoing twice weekly treatments for 6 months without signs of lesion recurrence. CONCLUSION: Concomitant use of systemic steroids and LPT showed a positive effect on controlling oral CP lesions and on improving both oral health and the quality of life of the patient.

Morphological, histochemical, and immunocytochemical study of CO2 and Er:YAG laser effect on oral soft tissues.

OBJECTIVE: The purpose of this study was to investigate the morphological, histochemical, and immunocytochemical changes of the oral mucosa after CO(2) or Er:YAG laser irradiation. BACKGROUND DATA: There have been no comparative reports on CO(2) and Er:YAG laser effects on human oral soft tissues. MATERIALS AND METHODS: Tissue preservation was studied in 40 oral biopsies of young patients obtained by CO(2) and Er:YAG laser surgery. Hematoxylin-eosin and Giemsa stains, PAS/diastase treatment, AE1 and AE2 cytokeratins, MiB1/Ki67, and bcl-2 immunoreactions were performed on the laser cut edges on formalin fixed, paraffin embedded biopsies. RESULTS: CO(2) laser biopsies show blisters, clefts and erosions of the epithelium. Intracellular edema and lengthened nuclei were also seen. The glycogen content results decreased in CO(2) laser biopsies. Good expression for cytokeratins and cell-cycle proliferation markers were found in Er:YAG biopsies, on the contrary the apoptosis marker was better expressed in CO(2) laser biopsies. CONCLUSION: The results suggest that Er:YAG laser may be routinely used in surgery, because of its minimal damage of the epithelial tissue, its low inflammatory reaction, its quicker healing process and its lower risk of scarring.

SEM analysis of dentin treated with the Er:YAG laser: a pilot study of the consequences resulting from laser use on adhesion mechanisms.

OBJECTIVES: The purpose of this study was to compare the morphological characteristics of lased dentinal surfaces obtained by chemical etching, which was applied either before or after laser treatment. The adhesive interface after the application of an adhesive-composite system on the above mentioned dentinal surfaces was also evaluated. MATERIALS AND METHODS: Eighteen caries-free permanent molars were transversally cut to obtain the dentinal surfaces. Ten of these surfaces were divided into three main groups according to their preparation modality: laser only, laser followed by chemical etching, and chemical etching before laser. The Er:YAG laser was used with two different energy outputs: 200 and 400 mJ at 1 Hz. The eight remaining surfaces were divided into two groups and followed the same preparation as the first three groups. The only difference was a change in frequency: 4 Hz was used for treating these surfaces. An adhesive system (Scotchbond 1, 3M), a thin layer of flowable composite (Tetric Flow, Vivadent), and a regular composite (Z250, 3M) were applied to each dentinal surface and then separately light cured. In order to evaluate the dentine-restoration interface, the samples were cut longitudinally and prepared for SEM observation. RESULTS: The dentinal surfaces that were etched by the laser treatment did not demonstrate the characteristics necessary for guaranteeing a good bond with the adhesive materials. A closer observation of the dentine-restoration interface revealed some micro-fractures located just below the lased dentinal surface. CONCLUSION: The decision to use the Er:YAG laser as an alternative to conventional techniques of acid etching is currently arguable. Given that the available adhesive systems require acid conditioning, it would not be advisable to skip this operative step.

Combined technique with polyethylene fibers and composite resins in restoration of traumatized anterior teeth.

Traumatized anterior teeth need quick esthetic and functional repair. Esthetic requirements of anterior teeth require the use of composite materials which, in the most complex cases, can be used in association with fibers so as to improve their mechanical resistance. Many kinds of fibers are available. The authors considered parameters such as physical properties, water absorption, ease of cutting and of laying. Polyethylene fibers appear to have the best properties in elasticity, translucency, adaptability, tenaciousness, resistance to traction and to impact. Fifteen children, between 7 and 13 years old, with crown fractures of the anterior sector were treated. In the case of a simple crown fracture, the missing part was restored by polyethylene fibers and composite resins. In the case of a complex crown fracture needing endodontic treatment, the fibers were used as a central core stump in order to restore the dental morphology. At control examinations, the teeth restored by this technique were acceptable, both in function and in aesthetics. Thus, the authors recommend this combined technique for predictable restoration of traumatized anterior teeth.