Gabriela Cristina de Oliveira

In vitro assessment of artificial saliva formulations on initial enamel erosion remineralization

OBJECTIVES Various formulations of artificial saliva are present in the literature and little guidance is available on the standardization of type of saliva for use in in vitro protocols for erosive studies. The aim of this study was to evaluate the remineralizing capacity of different formulations of artificial saliva on initial enamel erosive lesion. METHODS Bovine enamel blocks were subjected to short-term acidic exposure by immersion in citric acid 0.05 M (pH 2.5) for 15s, resulting in surface softening without tissue loss. Then 90 selected eroded enamel blocks were randomly and equally divided into 6 groups according to saliva formulation (n=15): Saliva 1 (contain mucin); Saliva 2 (Saliva 1 without mucin); Saliva 3; Saliva 4; Saliva 5 (contain sodium carboxymethyl cellulose) and control (C) (deionized water). After demineralization enamel blocks were subjected to remineralization by immersion in the salivas formulations for 2h. Enamel remineralization was measured by superficial hardness test (% superficial hardness change). The data were tested using ANOVA and Tukeys test (p<0.05). RESULTS All the tested formulations of artificial saliva resulted in significantly higher enamel remineralization compared to control (p<0.001). Saliva 3 showed higher percentage of enamel remineralization than Saliva 5 (p<0.05). CONCLUSIONS Besides the variety of artificial saliva for erosion in vitro protocols, all the formulations tested were able to partially remineralize initial erosive lesions.

Susceptibility of bovine dental enamel with initial erosion lesion to new erosive challenges

This in vitro study evaluated the impact of initial erosion on the susceptibility of enamel to further erosive challenge. Thirty bovine enamel blocks were selected by surface hardness and randomized into two groups (n = 15): GC- group composed by enamel blocks without erosion lesion and GT- group composed by enamel blocks with initial erosion lesion. The baseline profile of each block was determined using the profilometer. The initial erosion was produced by immersing the blocks into HCl 0.01 M, pH 2.3 for 30 seconds, under stirring. The erosive cycling consisted of blocks immersion in hydrochloric acid (0.01 M, pH 2.3) for 2 minutes, followed by immersion in artificial saliva for 120 minutes. This procedure was repeated 4 times a day for 5 days, and the blocks were kept in artificial saliva overnight. After erosive cycling, final profile measurement was performed. Profilometry measured the enamel loss by the superposition of initial and final profiles. Data were analyzed by t-test (p<0.05). The result showed no statistically significant difference between groups (GS = 14.60±2.86 and GE = .14.69±2.21 μm). The presence of initial erosion on bovine dental enamel does not enhance its susceptibility to new erosive challenges.

Influence of removing excess of resin-based materials applied to eroded enamel on the resistance to erosive challenge

OBJECTIVES The aim of this study was to evaluate the effect of removing excess of resin-based materials applied to eroded enamel, subjected to erosive challenge. METHODS Bovine enamel blocks were immersed in HCl 0.01M, pH 2.3, for 30s under agitation at 50 rpm in room temperature, in order to form a softened erosion lesion. The blocks were then randomly divided into eight groups (n=12) and treated as follows: Cn- and Ce-control without treatment, Hn- and He-fissure resin sealant (Helioseal Clear(®)), An- and Ae-self-etch adhesive (Adhese(®)), In- and Ie-infiltrant (Icon(®)); being n-with excess removal and e-without excess removal of the material. After application of the materials, the blocks were immersed in HCl for 2 min, followed by immersion in artificial saliva for 120 min. This cycle was repeated four times a day for five days. Material thickness and enamel wear were assessed using profilometry. Data were analyzed by two-way ANOVA and Tukeys test (P<0.05). RESULTS Groups He, Ae, and Ie resulted in the formation of a layer of material over enamel, being similar effective in inhibiting erosion progression (P>0.05). Groups Hn, An, and In (with excess removal) were similar to controls (Cn, Ce) and resulted in near enamel loss after application and after erosive challenge (P>0.05). CONCLUSIONS Resin-based materials are able to protect enamel against erosion only when they are present over enamel, as a physical barrier. CLINICAL SIGNIFICANCE The resin-based materials demonstrated potential to prevent the progression of erosion lesions when the material remains on the dental surface.

The Effect of Mucin in Artificial Saliva on Erosive Rehardening and Demineralization

The effect of mucin in artificial saliva on rehardening (RE-experiment) and inhibition (DE-experiment) of erosion was evaluated. The treatment groups were: artificial saliva with mucin, artificial saliva without mucin, human saliva, and water. For the RE-experiment, after immersion of enamel blocks in citric acid (4 min), hardness was measured and blocks were subjected to treatment for 2 h. For the DE-experiment, sound blocks were subjected to treatment for 2 h and immersed in citric acid (4 min). Percentages of hardness recovery (RE) and loss (DE) were analyzed (ANOVA/Tukeys test). The salivas promoted similar rehardening, but only the saliva with mucin was similar to human saliva with regard to enamel protection against erosion.

In situ effect of CPP-ACP chewing gum upon erosive enamel loss

Abstract Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) is able to increase salivary calcium and phosphate levels at an acidic pH. Previous studies demonstrated that a CPP-ACP chewing gum was able to enhance the re-hardening of erosion lesions, but could not diminish enamel hardness loss. Therefore, there is no consensus regarding the effectiveness of CPP-ACP on dental erosion. Objective This in situ study investigated the ability of a CPP-ACP chewing gum in preventing erosive enamel loss. Material and Methods: During three experimental crossover phases (one phase per group) of seven days each, eight volunteers wore palatal devices with human enamel blocks. The groups were: GI – Sugar free chewing gum with CPP-ACP; GII – Conventional sugar free chewing gum; and GIII – No chewing gum (control). Erosive challenge was extraorally performed by immersion of the enamel blocks in cola drink (5 min, 4x/day). After each challenge, in groups CPP and No CPP, volunteers chewed one unit of the corresponding chewing gum for 30 minutes. Quantitative analysis of enamel loss was performed by profilometry (µm). Data were analyzed by Repeated-Measures ANOVA and Tukey’s test (p<0.05). Results The use of chewing gum (CPP and No CPP) resulted in lower erosive enamel loss compared with the control group (p<0.05). CPP-ACP chewing gum (CPP) did not improve the protection against erosive enamel loss compared with conventional chewing gum (No CPP) (p>0.05). Conclusion The CPP-ACP chewing gum was not able to enhance the anti-erosive effect of conventional chewing gum against enamel loss.

Posttraumatic Displacement Management: Lateral Luxation and Alveolar Bone Fracture in Young Permanent Teeth with 5 Years of Follow-Up

Dental trauma is an important public health problem due to high prevalence and associated limitations. The external impact accounting for trauma may result in different injury types to teeth and supporting structures. This paper describes a clinical case of tooth trauma in an 8-year-old patient exhibiting the displacement of three permanent teeth with open root apexes. Although the traumatic impact resulted in two injury types to teeth and supporting tissues (lateral luxation and alveolar bone fracture), the therapeutic approach was the same in both situations. The bone and teeth were repositioned by digital pressure, stabilized by semirigid splint, and followed up at every week. After six weeks, the splint was removed. At that moment, the clinical and radiographic findings indicated normal soft/hard tissues and absence of pulp/periodontal pathologies. At the fifth year of follow-up, the treatment success of the case was confirmed, although it has been observed that all lower incisors exhibited pulp obliteration as a consequence of the dental trauma.

Delayed Treatment of Traumatized Primary Teeth with Distinct Pulp Response: Follow-Up until Permanent Successors Eruption

Complicated crown fracture and crown-root fracture with pulp involvement expose dental pulp to the oral environment. The pulp outcome is often unpredictable because the patient and injury which are related to variables can influence the treatment of choice and the prognosis of the case. This report presents the case of a 4-year-old boy with complicated crown fracture with pulp polyp in the primary right maxillary central incisor (51) and crown-root fracture with pulp involvement in the primary left maxillary central incisor (61), which was treated only 3 months after the tooth injuries. The treatment of choice was extraction of tooth (61) due to a periapical lesion with disruption of the dental follicle of the permanent successor and pulpotomy (MTA) of the tooth (51), because the pulp presented signs of vitality. At the follow-up visits, no clinical, symptomalogical, and radiographic changes were observed until the primary tooths exfoliation. However, at 3-year follow-up, the permanent successors showed hypocalcification and the position of the permanent right maxillary central incisors (11) was altered. Besides the conservative and adequate delayed treatment, the sequelae on the permanent successors could not be avoided.

Impact of Saliva and Intraoral Appliance on Erosion Lesions Rehardening Ability - A Pilot Study

Objective: To evaluate the ability of different periods of salivary exposure and two different removable appliances to rehardening initial erosive lesions. Material and Methods: This randomized, single blind in situ study was conducted with 2 crossover phases. The factors under study were: period of salivary exposure (15 minutes, 30 minutes, 1 hour and 2 hours) and type of oral appliance (maxillary or mandibular). Two hundred enamel blocks were selected by initial surface hardness (SHi). Enamel blocks were demineralized in vitro (0.05M citric acid; pH2.5 for 15 seconds), surface hardness (SHd) was remeasured and 160 blocks were selected and randomized among groups. Thus, there were 2 blocks per period of salivary exposure in each type of oral appliance for each one of the 10 volunteers. In each phase, one of the removable appliances was tested. The response variable was percentage of surface hardness recovery (%SHR=[(SHf-SHd)/SHi)]x100). Two-way ANOVA and Tukey’s post hoc test were applied adopting 5% of significance. Results: No difference was found among oral appliances on enamel rehardening (p>0.01). Salivary exposure of 2 hours promoted similar enamel rehardening when compared to 1 hour (p>0.05), which showed similar rehardening to 30 min. All mentioned period of salivary exposure promoted superior rehardening than 15 min (p>0.01). Conclusion: The salivary time exposure between erosive attacks might be 2 hours to achieve a feasible maximum rehardening. In addition, both maxillary and the mandibular appliance have presented a similar rehardening ability.