Tooth eruption involves a complex developmental process of tooth migration from the dental follicular origin to the final occlusion position in the oral cavity via the alveolar process. Disturbance of tooth eruption can occur at any point in a series of eruption stages; however, horizontal impaction of the mandibular first molar and primary retention of the primary mandibular second molar are rarely observed simultaneously. This study describes the treatment for two cases of horizontally impacted first molar with primary retention of primary molar. The primary retention of the primary mandibular second molar was extracted, and orthodontic traction was applied to the horizontally impacted primary mandibular first molar. Subsequently, displacement of the premolar tooth bud was improved and space regaining for eruption was achieved, guiding to normal eruption of the first molar.

The purpose of this study was to compare the success rates of two pulp capping materials, BiodentineTM and RetroMTA®, used for partial pulpotomy in permanent molars after carious exposures and to compare the final restorative outcome of using composite resin to that of using a stainless steel crown. We studied children who were diagnosed with dental caries of permanent molars and underwent partial pulpotomy. The patients were followed up for more than 1 year. Clinical and radiographic evaluation were used to evaluate the success of each treatment. Fisher's exact test was used to compare the outcomes of two groups. For pulp capping agents, the success rate of using RetroMTA® was lower than that of using BiodentineTM(p < 0.05). Final restoration with composite resin was less successful than restoration with an stainless steel crown(p < 0.05). In combination of pulp capping agents and final restoration material, RetroMTA®- composite resin shows the lowest success rate(p < 0.05).

This study was performed to evaluate the effectiveness of the 2-step needle insertion technique to reduce pain during local anesthesia in children. Local anesthesia was performed bilaterally using conventional technique and a 2-step technique, and to compare the degree of pain using the 2-step with that using the conventional technique during local anesthesia using a pain scale.
The pain scores were significantly different between the conventional technique and the 2-step insertion technique at 5.82 ± 2.14 and 2.57 ± 2.09, respectively (p < 0.001). The subjective degree of pain based on gender, age, and Frankl’s behavior rating scale was significantly lower in the 2-step insertion technique (p < 0.001). Subjective pain levels in the area of maxilla and mandible, anterior and posterior parts were lower in the group treated using the 2-step insertion technique (p < 0.001).
The 2-step insertion technique is a simple and effective way to reduce pain during local anesthesia not only in children with a positive attitude to dental treatment, but also in children with negative attitudes, and is thought to be more effective if combined with application of topical anesthesia or distraction.

Traumatic bone cyst (TBC) is an asymptomatic lesion seen most in adolescents. TBC is found incidentally on routine panoramic examinations and appears as a relatively well-demarcated unilocular radiolucency with scalloped margins. Histological examination reveals a vacant cavity of cancellous bone usually unlined or very occasionally lined with a thin connective tissue layer. The lack of lining epithelial membrane is common histological feature. The most affected site is between the mandibular canine and third molar. The involvement of the mandibular symphysis is rare. The etiopathogenesis of the TBC is unclear. TBC is treated with surgical exploration and curettage; new bone is formed in place of the lesion within 6 - 12 months of surgery. Diagnosis of TBC prior to surgical intervention has limitations in most of the cases. Both of our patients were diagnosed through radiological examination and biopsy. Neither patient had a history of trauma. After surgery, the panoramic radiograph and CBCT were used to confirm bone healing.

The purpose of this study was to compare the values of tongue pressure (TP), lip closing pressure (LCP), right buccal pressure (RBP), and left buccal pressure (LBP) and check the intraoral muscle imbalance and observe the changed values according to the myofunctional therapy (MFT) period. The MFT with a prefabricated appliance was performed on patients with certain muscular dysfunctions due to oral habits. And the improvement of perioral muscles was evaluated using a balloon-based pressure measurement. The group consisted of 21 patients with oral habits such as chronic mouth breathing, finger sucking, lip sucking, tongue thrusting, and atypical swallowing habits. When comparing the two groups before treatment, there was a significant difference in TP and LCP values. The TP increased the most in the first month since the start of myofunctional therapy, and the LCP increased the most between 3 and 6 months after treatment began. The values of TP, LCP, RBP, and LBP in the control group measured before treatment were very similar to the results of the experimental group 6 months after the myofunctional therapy. When the MFT was steadily performed, it was possible to observe a noticeable increase in the tongue and lip closing pressure. At least 6 months of myofunctional therapy is recommended for patients with intraoral muscle imbalance due to oral habits.

The purpose of this study is to evaluate changes of occlusion following the placement of preformed metal crown in the permanent first molar affected by severe caries or hypomineralization.
The study was conducted on 24 patients who met the criteria among the patients with occlusion in the permanent first molar reaching the occlusal plane. Restorative treatment was performed on one first molar using preformed metal crown. Before treatment, immediately after treatment, after 4 weeks, and after 8 weeks, the T-scan Ⅲ was used for measuring distribution of bite force at the maximum intercuspal position, and overbite was measured with digital vernier calipers and change of dental midline was surveyed. After 8 weeks, questionnaires survey was conducted.
In most cases, immediately after treatment, the distribution of bite force between the restored side and non-restored side of arch was reversed compared to before treatment, and the overbite was decreased. However, after 4 weeks, bite force of the left and right side was balanced and the distribution of bite force on the restored and non-restored permanent first molars had similar values. Also, the changed overbite and midline were returned to pre-treatment status and there was no significant temporomandibular joint and masticatory discomfort after treatment.
In this study, it was confirmed that spontaneous occlusal equilibrium was achieved one month after the placement of preformed metal crown.

Stevens-Johnson syndrome (SJS) is a severe adverse cutaneous drug reaction seen rarely in clinical practice. Although relatively rare, the condition can be fatal. Mainly, it is caused by side effects of certain medications. Previous reports have associated Stevens-Johnson syndrome with abnormal root development, but the other long-term dental complications have rarely been reported. In this case, the patient developed SJS at the age of 5, and abnormal root development of the maxillary and mandibular first molars and mandibular incisors was observed, as well as impaction of the mandibular canine and enamel hypomineralization of multiple teeth. Accordingly, appropriate restorative treatment and orthodontic treatment were performed, and the clinical characteristics of this symptoms and its treatment were discussed in more detail. We aim to highlight the need for dentists to be aware of the potential dental complications of SJS and to enable early diagnosis and management of the condition to avoid undesirable sequelae.

The purpose of this study was to compare the remineralization effect of 38% silver diamine fluoride (SDF) and 5% sodium fluoride (NaF) varnish on artificially induced enamel caries.The present study standardized the physiochemical characteristics of the tooth structure using bovine teeth, realized the wash-off action of agents using a saliva, reproduced an environment similar to mouth through pH-cycling, and comparatively assessed the remineralization effect of 38% SDF and 5% NaF varnish in a non-destructive method using micro-CT. And the remineralized enamel surface structure was analyzed by scanning electron microscopy (SEM) and energy dispersive X-Ray spectroscopy (EDS). In both SDF and NaF varnish, mineral density (△Hounsfield unit value) and the volume of enamel restored to normal mineral density through remineralization gradually increased with time. And the SDF showed a much higher level of increase in mineral density at all depths and remineralized volume than NaF varnish. According to SEM analysis, the surface roughness decreased in the order of artificial saliva, NaF varnish and SDF. In addition, EDS analysis showed that silver ion was precipitated on the enamel surface in SDF group. In conclusion, SDF had a greater remineralization effect than NaF varnish on demineralized enamel.

The objective of this study is to analyze the shear bond strength of orthodontic buttons according to light tip distance and optic fiber diameter when an extended optic fiber was applied to the tip of a curing light unit.
In this study, 315 extracted premolar teeth were divided into 3 groups. Orthodontic buttons were attached using no optic fibers (Group I), 3.0 mm diameter optic fibers (Group II), or 5.0 mm diameter optic fibers (Group III). Each group was divided into subgroups A - C (5.0, 10.0, and 15.0 mm light tip distance), respectively. Shear bond strength was then measured while varying the light tip distance.
In group I, shear bond strength significantly decreased as the light tip distance increased. When the shear bond strength was evaluated according to the optic fiber diameter, no statistical significance was observed in group of 5.0 mm light tip distance. Compared with group IB, group IIIB showed significantly greater shear bond strength. Compared with group IC, all groups using 3.0 or 5.0 mm diameter optic fibers showed significantly greater shear bond strength.
Therefore, when a curing light unit has poor accessibility, optic fibers with a large diameter should be considered.

The purpose of this study was to evaluate the effect of virtual reality distraction on pain and anxiety in children during local anesthesia. Local anesthesia was administered to 3 groups: a control group without distraction, a group watching TV, and a group using a virtual reality device. The pulse rate and oxygen saturation rate were measured before and at the time of local anesthesia to assess the patients’ pain and anxiety, and the Wong-Baker Faces Pain Rating Scale was completed after local anesthesia.
The group using the virtual reality device had a significantly lower heart rate change and lower Wong-Baker Faces Pain Rating Scale score than those in the control group and the group watching TV (p < 0.05). The greatest difference in heart rate change and Wong-Baker Faces Pain Rating Scale score, between the control and virtual reality distraction groups, was seen in 5 - 7-year-olds and a Frankl’s behavior rating scale grade of 3.
The virtual reality device alleviated pain and reduced anxiety in children during local anesthesia.