BACKGROUND: This paper reports a rare presentation of multiple pulp stones (PSs) emerging in all teeth during mixed dentition. It offers valuable insights into the clinical diagnosis, treatment, and prognosis of multiple PSs, shedding light on their occurrence during the mixed dentition period.
METHODS: A 10-year-old girl presented with repeated pain in the mandibular right posterior teeth. Intraoral examination revealed carious lesions, abnormal tooth shapes, and anomalies in tooth number. Radiographic examinations showed multiple PSs with diverse shapes, sizes, and quantities in all teeth, alongside anomalies in tooth shape and number. Root canal therapy was initiated, but the patient initially lacked timely follow-up. Upon return for treatment completion, an extracted tooth revealed irregular calculus within the pulp cavity.
CONCLUSIONS: This case underscores the importance of considering multiple PSs in mixed dentition, necessitating comprehensive evaluation and management strategies.

OBJECTIVE: To investigate the efficacy of block iliac bone grafting in patients with unilateral alveolar cleft in mixed dentition.
METHODS: A retrospective study was conducted on patients with unilateral alveolar clefts in mixed dentition who were treated in the Department of Oral and Maxillofacial Surgery, Fujian Medical University Union Hospital. All patients underwent unilateral alveolar cleft bone graft repair with autogenous block iliac bone blocks. The healing of bone blocks was analyzed at 1 week and 6-12 months after surgery. Mimics software was used for the three-dimensional reconstruction and volumetric measurement of the iliac bone blocks on the follow-up imaging data of 15 patients aged 9-12 years without the eruption of canines before surgery, and the bone resorption rate of the iliac bone blocks was comparatively analyzed.
RESULTS: In the 37 patients, bone grafting was successful in 32 and failed in five. The success rate of bone grafting was 86.5%. In 15 patients aged 9-12 years without the eruption of canines before surgery, eruption through the bone graft area was observed in two patients 6-12 months after the operation. Cone beam computer tomography showed that the grafted bone block exhibited good bony connections, and its resorption mainly occurred on the crests and palatal sides of the alveolar ridge. Bone resorption rates varied considerably between patients with a mean bone resorption rate of 39.0%±13.8% at 6-12 months after surgery.
CONCLUSIONS: For patients in mixed dentition, bone grafting with block iliac bone can achieve better osteogenesis effect.
目的: 探究替牙期单侧牙槽突裂患者行块状髂骨移植术的疗效情况。方法: 回顾性研究就诊于福建医科大学附属协和医院口腔颌面外科的采用自体半厚块状髂骨块进行单侧牙槽突裂植骨修复的替牙期患者37例。植骨术后1周、术后6~12个月随访观察，并通过Mimics软件对15例患者（术前恒尖牙未萌出的9~12岁患者）的随访影像资料进行髂骨块的三维重建和体积测量，对比分析髂骨块骨吸收率。结果: 37例患者中，32例植骨成功，5例植骨失败。植骨成功率为86.5%。术前恒尖牙未萌出的9~12岁的15例患者中，有2例在术后6~12个月尖牙自行经植骨区萌出；锥形束CT示移植骨块出现良好的骨性连接，其吸收主要发生在牙槽嵴顶处和腭侧，不同患者之间的骨吸收率差异较大，术后6~12个月的平均骨吸收率为39.0%±13.8%。结论: 对替牙期牙槽突裂患者采用块状髂骨植骨术可获得较好的成骨效果。.

The mixed dentition stage is the period between primary and permanent dentition. The following biological processes are complicated and variable: jaw growth, development of inherited permanent teeth embryo, physiological absorption of primary teeth, restoration of surrounding alveolar bones, and growth and function establishment of soft tissues. For the normal development of the jaw, the establishment of the good occlusion relationship, development, and function of soft tissue is very important, whether or not the primary teeth are normally replaced by the permanent teeth in the mixed dentition stage. The eruption space is linked to the normal replacement of primary and permanent teeth. The presence of a mixed dentition space results in the incidence and progression of malocclusion and impacts the normal growth and development of the occlusion, jaw, and face. Space management in the mixed dentition stage is a crucial means to prevent and reduce malocclusion. The following were discussed and analyzed: the possible space problems, why the size of the space was affected, the content that needs to be assessed, and the methods of space management in the mixed dentition that can be used to unify and standardize the management of mixed dentition. This paper was developed to serve as a guide for regulated space management during the mixed dentition period.
混合牙列期是乳牙列向恒牙列转化的过渡期，生物学过程复杂多变，伴随颌骨生长、继承恒牙胚发育、乳牙牙根的生理性吸收、周围牙槽骨的改建及软组织的生长和功能的建立。混合牙列期的乳恒牙是否正常替换，对颌骨的正常发育、良好咬合关系的建立和软组织的发育及其功能发挥起着十分重要的影响。而乳恒牙的正常替换与恒牙萌出间隙密切相关。混合牙列间隙异常不仅直接关系此期错牙合畸形的发生、发展，甚至影响牙合、颌及面的正常生长发育。因此，混合牙列期的间隙管理是预防、降低错牙合畸形发生率及严重程度的重要手段。本文从混合牙列期可能出现的间隙问题、影响间隙大小的原因、混合牙列期间隙管理需要评估的内容和间隙管理的方法等方面进行讨论和分析，以期为规范化混合牙列期间隙管理提供参考。.

UNASSIGNED: Malocclusion, a common oral health problem in children, is associated with several contributing factors. This study aimed to investigate the prevalence of mixed dentition stage malocclusion and its contributing factors in Chinese Zhuang children aged 7-8 years.
UNASSIGNED: Overall, 2,281 Zhuang children, about 7-8 years old, were randomly selected using a stratified whole-cluster sampling method from schools in counties in Northwestern Guangxi, China. The children were examined on-site for malocclusion and caries by trained dentists, and basic data on the children were collected using questionnaires, including age, sex, parental education, parental accompaniment, and children\'s knowledge of malocclusion and treatment needs. Data were analyzed using the chi-square test and logistic regression analysis.
UNASSIGNED: The total prevalence of malocclusion in Zhuang children aged 7-8 years was 58.5%, with the highest prevalence of anterior crossbite tendency, and the prevalence of anterior crossbite and anterior edge-to-edge occlusion was 15.1% and 7.7%, respectively. This was followed by an anterior increased overjet of 13.3% and an inter-incisor spacing of 10.3%. The lowest prevalence was 2.7% for anterior open bite. Sex, parental accompaniment, parental education, and decayed, missing, and filled teeth of the first primary molar were factors that contributed to malocclusion in Zhuang children.
UNASSIGNED: Malocclusion is a common oral problem among Zhuang children. Therefore, more attention must be paid to the intervention and prevention of malocclusion. The impact factors should be controlled as early as possible.

Invisalign First System (First) is a new type of orthodontic appliance for maxillary arch expansion in mixed dentition children. Till now, few studies have evaluated the expansion effects of First versus other appliances. What\'s more, most studies of arch expansion did not include a natural group to rule out growth effects. This prospective cohort study aimed to evaluate the dental and dentoalveolar effects using First or acrylic splint rapid maxillary expander (RME) in adolescents excluding growth factors.
After screening by strict inclusion criteria and propensity score matching (PSM), fifty-one patients were included: First group (n = 17), RME group (n = 17), and natural growth (NG) group (n = 17). Nine indicators including dental arch width, dentoalveolar arch width, and inclination of the molars were measured on digital dental casts at baseline (T0) and six-month follow-up (T1). Paired t-tests were used for intra-group results, and two-sample independent t-tests were used for inter-group comparisons.
There was no significant increase in all indicators within six months in the NG group (p > 0.05). In the First group and RME group, all width indicators were significantly increased after treatment (p < 0.05). The RME group exhibited greater expansion than the First group in intercanine width, first interpremolar width, second interdeciduous molar width, first intermolar width, arch perimeter, intercanine dentoalveolar width, intermolar dentoalveolar width, and inclination of the molars (p < 0.05). Whereas, there was no significant difference in arch depth between the two treated groups.
Both First and RME can expand the maxillary arch in mixed dentition. In case of mild to moderate maxillary transverse deficiency (MTD), Invisalign First System could be a reasonable option. RME shows significant better efficiency of dental arch expansion than First, recommended for patients with severe MTD.
This prospective study was registered on ClinicalTrials.gov (01/02/2022, registration number: ChiCTR2200056220). The trial was approved by the Ethical Committee of the Hunan Xiangya Stomatological Hospital Central South University (20,200,088), and informed consent was obtained from all subjects and their legal guardian(s).

To compare the differences in salivary metabolites between caries-active and caries-free children in the mixed dentition, and explore their correlation with caries status.
The study involved 20 children (aged 8-9 years) in the mixed dentition, including 10 caries-active (aged 8.6 ± 0.49years) and 10 caries-free children(aged 8.5 ± 0.5years), with a male/female ratio of 1:1. The saliva samples were collected from all children. Metabolite extraction, LC-MS/MS-based untargeted metabolomics, qualitative and semi-quantitative analysis and bioinformatics analysis were performed to identify differential metabolites between the two sample groups. The differential metabolites identified were further analyzed in an attempt to find their correlations with caries status.
In the positive ion mode, a total of 1606 molecular features were detected in the samples of the two groups, 189 of which were differential metabolites when comparing the caries-active group with the caries-free group, including 104 up-regulated and 85 down-regulated metabolites. In the negative ion mode, a total of 532 molecular features were detected in the samples of two groups, 70 of which were differential metabolites when comparing the caries-active group with the caries-free group, including 37 up-regulated and 33 down-regulated metabolites. In the positive ion mode, two of the top 5 up-regulated differential metabolites were found in and annotated to specific metabolic pathways, whereas in the negative ion mode, only one of the top 5 up-regulated differential metabolites was found in and annotated to specific metabolic pathways. In both the positive and negative ion modes, the top 5 down-regulated differential metabolites were both annotated to the metabolic pathways. KEGG pathway enrichment analysis of differential metabolites showed that histamine and arachidonic acid identified in the positive ion mode, as well as succinate and L-histidine identified in the negative ion mode were enriched in the top 3 significantly altered pathways.
The enriched differential metabolites including histamine, L-histidine and succinate were correlated with the presence of dental caries, but their role in the caries process needs to be further investigated.

Various preformed early orthodontic appliances for correcting oral habits and training orofacial muscles have emerged on the market. However, there are few reports on the effectiveness of these appliances for orofacial myofunctional training.
This retrospective study evaluated children with lip incompetence and mixed dentition treated at the Pediatric Dentistry Department of Shanghai Ninth People\'s Hospital from 2016 to 2018. A total of 109 children (54 males, 55 females; age range: 7-10 years, mean age: 8.2 years) were selected from an overall sample of 870 patients. During the first visit, all patients were instructed to perform active lip and tongue training at home daily and were divided into two groups according to the kind of appliances worn. The first group consisted of 56 subjects (30 females; 26 males), with a mean age of 8.1 years (SD 1.1 years), treated with preformed appliances. The second group consisted of 53 subjects (25 females; 28 males), with a mean age of 8.2 years (SD 1.0 years), treated with conventional early orthodontic appliances (arch expansion devices along with \"2*4\" local fixed appliances). For each subject in the two groups, initial (pretreatment, T1) and final (posttreatment, T2) intraoral and external photos, dental casts, lateral cephalograms, and orthopantograms were taken, and lip strength was measured. SNA, SNB, ANB, APDI, FMA, U1SN, and IMPA before and after treatment were measured by The Dolphin Imaging Cephalometric Analysis Software. The hyoid bone position was also recorded. Differences between groups were identified with an independent sample t-test (P < 0.05).
In the first group, a statistically significant forward movement of the mandible was detected by an increase in SNB of - 1.06 degrees (P < 0.01) and an increase in APDI of - 2.23 degrees (P < 0.01). The increase in IMPA (- 3.21 degrees, P < 0.01) demonstrated a statistically significant protrusion of the lower incisors. Lip strength significantly increased (- 2.44, P < 0.01). The increase in HC3 (- 1 mm, P < 0.01) and HFH (- 2.95 mm, P < 0.01) implied a forward and downward movement of the hyoid bone. In the second group, a statistically significant forward movement of the mandible was also detected by an increase in APDI of -1.96 degrees (P < 0.01). Lip strength also significantly increased (- 1.24, P < 0.01). The increase in HFH (- 2.55 mm, P < 0.01) implied a downward movement of the hyoid bone. Compared with the treatment in the second group, orofacial myofunctional therapy combined with the preformed appliances led to a statistically significant lip strength increase (- 2.30, P < 0.05). Significant differences were observed in SNB and IMPA between the two groups (P < 0.05).
Orofacial myofunctional therapy effectively improved patient lip strength and was a good option for mixed dentition patients with lip incompetence. Preformed appliances could enhance the orofacial myofunctional therapy effect and result in significant improvements in lip strength and forward movement of the mandible, which can optimize the jaw relationship.

OBJECTIVE: We aimed to investigate the composition and functions discrepancy of supragingival plaque associated with active deciduous teeth caries in mixed dentitions.
METHODS: Thirty-three subjects with mixed dentition participated in this study. Children with deciduous teeth caries (dt ≥ 3) were recruited to the caries group, whereas children without deciduous teeth caries (dt = 0) were recruited to the caries-free group. Plaque were collected from deciduous teeth surface and permanent teeth surface respectively. A total of 66 samples of dental plaque were collected and conserved. Illumina 16S rRNA sequencing and diversity analysis were performed for microbiome. Untargeted liquid chromatograph-mass (LC-MS) and partial least squares discriminant analysis were performed for metabolome.
RESULTS: A dominant microbiome of 8 phyla and 22 genera were detected. The alpha diversity indices did not detect differences between the caries and caries-free groups (p > 0.05). Beta diversity analysis showed that the microbiota composition was similar between subgroups. Comparative analysis at genus level did not detect difference between caries and caries-free subgroups. The metabolomics analysis yielded 419 biochemical metabolites, 56 of which were related to caries status. Metabolites in glucose metabolism and byproducts of oxidative stress were identified as related to dental caries in mixed dentition. Dominant bacteria are positively correlated with metabolites, such as Streptococcus and organic acids.
CONCLUSIONS: The upgrade of glucose metabolism and oxidative stress was observed in caries status. Functions discrepancy of oral microbiome may be more pronounced than the composition of oral microbiome with active dental caries in mixed dentitions.

OBJECTIVE: To evaluate the clinical effectiveness of the eruption guidance appliances (EGAs) in treating malocclusion in the early mixed dentition.
METHODS: Electronic databases were comprehensively searched for the eligibility literature of the EGA treatment for a period spanning from the earliest available date in each database up to July 2021. Randomized controlled trials, controlled clinical trials, and prospective and retrospective cohort studies were included in the present review. The quality of clinical trials was assessed according to the Cochrane Collaboration\'s tools (RoB2.0 and ROBINS-I), whereas cohort studies were based on the Newcastle-Ottawa Scale (NOS). The data were gathered and synthesized with the Stata software (version 12).
RESULTS: The screen yielded 436 articles, of which 17 papers were potentially eligible, and 7 articles from 3 studies (1 RCT, 1 CCT, and 1 PCS) were qualified for the final review and analysis. The meta-analysis showed both favorable dentoalveolar and skeletal changes in short term. Both overjet and overbite had a significant decrease after treatment (MD = -2.38 mm, 95% CI: -2.82 to -1.94, p < .001, and MD = -2.43 mm, 95% CI: -3.52 to -1.35, p < .001, respectively), and SNB increased significantly by 0.73 degrees (95% CI: 0.17-1.28, p = .01). After the retention period, however, overbite had a significant increase of 0.88mm, which indicated the occurrence of a relapse (95% CI: 0.60-1.16, p < .001).
CONCLUSIONS: According to the existing evidence, the EGA treatment is effectively correcting overjet and overbite in the early mixed dentition in short term; furthermore, high-quality and long-term studies are warranted to determine its long-term effectiveness.

OBJECTIVE: Leeway space is clinically crucial in pediatric dentistry because it is utilized to resolve tooth crowding and allow the first molars to drift mesially to establish a Class I molar relationship in the later stages of mixed dentition. This study investigated leeway space in the mixed dentition of Taiwanese children of different sexes and ages.
METHODS: The digital panoramic dental films of 182 lower arches of 119 boys and 63 girls aged 5-10 years were analyzed in this retrospective study. The mesiodistal crown widths of the primary canines and first and second molars and the permanent canines and first and second premolars were measured using medical imaging software. Differences in leeway space were statistically analyzed.
RESULTS: The average leeway space was 1.29 ± 1.48 mm on each side of the lower arch. The leeway space of children aged 5-6 years was significantly greater than that of children aged 7-8 years. No gender difference in crown width was discovered, except with regard to the primary first molar. Although no gender difference in leeway space was observed, permanent teeth affected leeway space more for girls than for boys.
CONCLUSIONS: In Taiwanese children, although leeway space does not differ by sex, age affects leeway space. However, permanent tooth size has an influence on the leeway space of girls.