This study analyzed the longevity of preformed metal crowns (PMCs) in first permanent molars and evaluated factors influencing their survival during a long-term follow-up period. In all, 115 first permanent molars treated with PMCs between June 2008 and June 2018 were retrospectively analyzed. The overall combined success rate for the study group was 84.3%. The 5-year survival rate was 82.8%. Multivariate Cox regression analyses identified distal cavities and mandibular PMC placement as risk factors for restoration failure. Careful placement of PMCs at the final try-in stage augments the longevity of the crown.

This retrospective study assessed the effectiveness and side effects of conscious sedation using chloral hydrate, hydroxyzine, and N2O/O2 in the sedation of 149 pediatric patients over 188 sedation sessions, and to identify associated variables.
The effectiveness of the sedation was evaluated using the Houpt scale, and was considered effective for scale categories of excellent or good. Effectiveness and side effects were assessed every 15 minutes. The effectiveness decreased and side effects increased over time. The effectiveness of sedation during 60 minutes was 57.4%, and one or more side effects occurred in 18.1% of sessions. Effectiveness of sedation increased with body mass index (BMI). When patients were sedated at the beginning of the procedure, the effectiveness was greater. Side effects increased with patient age. When sedation was divided into two sessions, the number of sedation did not affect the effectiveness or side effects.
It can be suggested that sedation should be performed over two separate sessions, as a single prolonged session may lead to reduced effectiveness and increased side effects. To maximize effectiveness and minimize side effects, several variables such as BMI, whether to sedate at the beginning of the procedure and age should be considered thoroughly before sedation.

Dilacerations generally involve central incisors; most often maxillary incisors rather than their mandibular counterparts. The clinical features of dilaceration include non-eruption of the responsible tooth or prolonged retention of the deciduous predecessor tooth. In Case 1, the tooth showed a dilaceration at the boundary between the crown and the root, more laterally rather than labiolingually. In Case 2, the dilacerated tooth showed a crown dilaceration with a relatively normal orientation of the dental root. In both cases, no significant space losses for eruption were observed. Moreover, it seems that unlike the maxilla with the palate, the mandibular anterior teeth are limited to show severe displacement.
From these cases, it is suggested that if a mandibular permanent incisor shows a crown dilaceration or lateral dilaceration at the boundary between the crown and the root, there is a relatively high probability of spontaneous eruption of the dilacerated tooth.

The purpose of this study was to investigate the characteristics related to the musculoskeletal disorders in pediatric dentists and general dentists. This study was conducted based on the survey results of a total of 109 dentists who have been working for the last year. Forty - three pediatric dentists and 66 general dentists were surveyed through online survey tool. Both pediatric dentists and general dentists mainly complained of musculoskeletal disorders in the neck, shoulders, wrists, and back. Most pediatric dentists usually suffered from back pain due to their unbalanced posture while giving dental treatments. Pediatric dentists in sedative treatment felt more pain in particular part of their body, such as neck and shoulder. Regular exercise and stretching for the prevention of musculoskeletal disorder have been shown to mainly relieve pain in the back but no other parts in their body.

In the root fracture, pulp necrosis tends to involve only the coronal fragment, while the pulp in the apical fragment remains vital. The prognosis of endodontic treatment of the apical fragment is poor due to the possibility of overfilling of the space between the fragments and difficulty in removing necrotic tissue.In the present cases, endodontic treatment of the apical fragment of root fracture was performed. However, in reendodontic treatment, resistance was felt at the fracture site and access to the root canal in the apical fragment was difficult. Therefore, the calcium hydroxide was periodically exchanged only in the coronal fragment without further treatment in the apical fragment and the canal of the coronal fragment was finally filled with Gutta-percha.Regular observation revealed no radiologic complications in the apical fragment. In some cases, we can observe good healing pattern such as absorption of calcium hydroxide and pulp canal obliteration of apical fragment in the long term.
Absorption ; Calcium Hydroxide ; Dental Pulp Cavity ; Dental Pulp Necrosis ; Gutta-Percha ; Prognosis ; Tooth

This study compared the microleakages and compressive strengths of various base materials.
To evaluate microleakages, 50 extracted permanent premolars were prepared. The teeth divided into 5 groups of 10 each according to the base materials. Cavities with a 5.0 mm width, 3.0 mm length, and 3.0 mm depth were formed on the buccal surfaces of the teeth. After filling the cavities with different base materials, a composite resin was used for final restoration. Each specimen was immersed in 2% methylene blue solution and then observed under a stereoscopic microscope (× 30). To evaluate the compressive strength, 5 cylindrical specimens were prepared for each base material. A universal testing machine was used to measure the compressive strength.
The microleakage was highest in the Riva light cureTM group and lowest in the BiodentineTM and Well-RootTM PT groups. For the compressive strengths, in all groups, acceptable strength values for base materials were found. The highest compressive strength was observed in the Fuji II LCTM group and the lowest strength in the Well-RootTM PT group.

Oral mucocele is a common exophytic lesion resulting from the accumulation of saliva due to pathological changes in the minor salivary glands. It is typically asymptomatic and painless and characterized by semipermeable, fluctuant nodules. General treatment methods for mucocele include surgical excision, marsupialization, cryosurgery, and steroid injection. This case report presents the treatment of oral mucocele using micro-marsupialization and a tying method as minimally invasive techniques rather than surgical treatment. Based on this case report, it is suggested that micro-marsupialization and the tying method can be used as alternative methods for the treatment of oral mucocele infants and children with behavioral control problems.

The purpose of this study is to analyze the fracture resistance of reattached tooth according to the resin materials and tooth preparation type under physiological conditions.
Uncomplicated crown fracture in the oblique direction was reproduced on the extracted 64 anterior teeth. Depending on the composite resin material, reattachment was performed using a flowable resin and a packable resin. Depending on retentive forms, reattachment was performed using simple reattachment, 1.0 mm × 1.0 mm labial chamfer bevel, 1.0 mm × 1.0 mm lingual chamfer bevel and 1.0 mm × 1.0 mm circumferential bevel. A load was applied to the palatal surface of the tooth using a universal testing machine at an angle of 125 degree, which is the interincisal angle of normal children. Under the masticatory pressure condition, fracture resistance of lingual chamfer groups was 28.28 ± 7.41 MPa and 27.54 ± 4.45 MPa, which was significantly higher than those of simple reattachment groups, 17.21 ± 5.87 MPa and 20.10 ± 6.00 MPa, in both flowable and packable resin groups.
When considering the lingual force similar to masticatory pressure, the fragment retention was significantly improved when the lingual chamfer was formed compared to the simple reattachment. Clinicians may consider the design of the lingual chamfer in order to improve fracture resistance to masticatory pressure during fragment reattachment.

The aim of this study was to evaluate the factors affecting the healing of root fracture in immature permanent teeth and the prognosis of root fracture by statistically analyzing the relationship with the pulp and root healing.The radiographs of 51 root-fractured maxillary anterior permanent teeth were collected. In radiograph, locations of root fracture, apical foramen width and width of diastasis between the fragments were measured. The value of the studied parameters were compared by independent t-test and rogistic regression test.In conclusion, there was no difference in the prognosis of pulp healing according to the location of root fracture. However, root healing occurs well as the root fracture is located at the root apex (p < 0.05). Lastly, the smaller the width of diastasis between the fragments after reduction, the better the pulp healing was (p < 0.05).
Prognosis ; Tooth Apex ; Tooth

The purpose of this study was to investigate the cause of eruption disturbance in the maxillary central incisor and establish the effective treatment plan by analyzing the vertical distance, angulation of long axis and root development of the tooth with eruption disturbance using the cone-beam CT.The average age of 134 patients diagnosed with unilaterally impacted maxillary central incisor was 7.9 years old and the male was 2.1 times higher than the female. The most common cause of eruption disorder was physical obstruction, especially mesiodens and odontoma. Of the teeth with unilateral eruption disorder, 78 cases erupted spontaneously and 56 cases erupted non-spontaneously after removal of physical obstruction.The possibility of spontaneous or non-spontaneous eruption in the unilaterally impacted maxillary central incisor depended on several factors, such as vertical distance, angulation of long axis and root development of unerupted tooth. The spontaneous eruption of the impacted maxillary cental incisor was most frequent at the angulation of long axis of 50 to 90 degrees, which is similar to the angulation of long axis of the normally erupted maxillary central incisor. In addition, the spontaneous eruption period of impacted maxillary central incisor was more influenced by the vertical distance than the angulation of long axis and the root development. Most of the teeth that showed non-spontaneous eruption had orthodontic traction, and these teeth were usually erupted within about 12 months. The period treated with orthodontic traction was no statistical significance with the vertical distance, the angulation of long axis, and the root development.This study will provide information on the cause of unilaterally impacted maxillary cental incisor and help to establish the future treatment plan.
Cone-Beam Computed Tomography ; Female ; Humans ; Incisor ; Male ; Odontoma ; Tooth ; Tooth, Impacted ; Tooth, Unerupted ; Traction