Chairside digital design and manufacturing method for children's band and loop space maintainers.

OBJECTIVES: This study proposes a chairside digital design and manufacturing method for band and loop space maintainers and preliminarily validates its clinical feasibility. METHODS: Clinical cases of 10 children requiring space maintenance caused by premature loss of primary teeth were collected. Intraoral scan data of the affected children were also collected to establish digital models of the missing teeth. Using a pediatric band and loop space maintainer design software developed by our research team, a rapid personalized design of band and loop structures was achieved, and a digital model of an integrated band and loop space maintainer was ultimately generated. A chairside space maintainer was manufactured through metal computer numerical control machining for the experimental group, whereas metal 3D printing in the dental laboratory was used for the control group. A model fitting assessment was conducted for the space maintainers of both groups, and senior pediatric dental experts were invited to evaluate the clinical feasibility of the space maintainers with regard to fit and stability using the visual analogue scale scoring system. Statistical analysis was also performed. RESULTS: The time spent in designing and manufacturing the 10 space maintainers of the experimental group was all less than 1 h. Statistical analysis of expert ratings showed that the experimental group outperformed the control group with regard to fit and stability. Both types of space maintainers met clinical requirements. CONCLUSIONS: The chairside digital design and manufacturing method for pediatric band and loop space maintainers proposed in this study can achieve same-day fitting of space maintainers at the first appointment, demonstrating good clinical feasibility and significant potential for clinical application.

Success rates and failures of fixed and removable space maintainers after the premature loss of primary molars.

OBJECTIVE: The evidence base for the use of space maintainers is relatively sparce despite being used for decades after the premature loss of primary molars. This study aims to increase the dental evidence base via investigating retrospectively the success rates of prefabricated fixed and removable space maintainers inserted from 2019 to 2021 and followed up until February 2023 at a specialized university clinic and to identify reasons for any reported minor and major failure. The authors hypothesized that there is no significant difference in failure rates between fixed and removable space maintainers inserted after the premature loss of a single primary molar per quadrant. METHOD AND MATERIALS: Patients' digital records were searched yielding 645 space maintainers. After the application of inclusion criteria, 157 (67%) fixed prefabricated space maintainers in 112 children and 77 (33%) removable space maintainers in 61 children were analyzed for an average of 18.4 ± 9.5 months. RESULTS: Kaplan-Meier survival analysis with Mantel-Cox statistics showed an overall cumulative survival time of 31.6 months (SE = 1.15, 95% CI = 29.4 to 33.9). Major failure occurred significantly more in removable maintainers (n = 40/67, 59.7%), mostly due to loss of the appliance, compared to fixed space maintainers (n = 27/67, 40.3%; P < .001). The present study indicates that space maintainers were mainly placed in young children with high caries experience, where treatment was mostly possible using advanced behavior management. CONCLUSIONS: Fixed space maintainers had a significantly lower failure rate than their removable counterpart. However, both require continual repairs, preservation, or even replacement till the eruption of the permanent tooth.

Development of a rapid-shaping and user-friendly membrane with long-lasting space maintenance for guided bone regeneration.

The success of guided bone regeneration (GBR) surgery depends largely on the use of GBR membranes to maintain space for bone regeneration and prevent soft tissue ingrowth. However, currently available commercial degradable GBR membranes are often limited by poor space maintenance ability and require additional suture or nail for fixation. To overcome these limitations, we developed a rapid-shaping, adhesive, and user-friendly GBR membrane (PLGA film-PGN) with long-lasting space maintenance by immersing an electrospun poly(lactide-co-glycolic acid) film in a photo-crosslinkable hydrogel composed of polyethylene glycol diacrylate, gelatin methacryloyl, and nanosilicate (PGN). The PGN hydrogel significantly improved the mechanical strength of the PLGA film-PGN and endowed it with plasticity and adhesive properties, making it more maneuverable. The maximum bending force that the PLGA film-PGN could withstand was over 55 times higher than that of the HEAL ALL film (a commonly used commercial GBR membrane). PLGA film-PGN also promoted the proliferation and osteogenic differentiation of rBMSCs. According to a critical-size rat calvarial defect model, PLGA film-PGN maintained the space within the defect area and significantly enhanced bone formation 4 weeks after the surgery. To conclude, the study provided a novel perspective on GBR membrane design and the multifunctional PLGA film-PGN membrane demonstrated great potential for bone defect reconstruction.

Arm design of band and loop space maintainer affects its longevity: a patient-specific finite element study.

Fixed space maintainers (FSMs) are commonly utilized in pediatric dentistry to prevent space loss following premature tooth extraction. Although previous studies have examined the survival rates and causes of FSM failure, the impact of arm design on failure has not been investigated. This study aimed to investigate the tensile and compressive stresses related to FSMs with different arm designs and evaluate the effect of arm designs on FSM failure. Cone beam computed tomography images of a child who experienced premature loss of a primary mandibular left second molar tooth were retrieved from our database, then processed and simulated using the Rhinoceros software. Finite element analysis was performed to evaluate the stresses on four distinct FSM arm designs under simulated chewing forces. The results showed that the straight-arm FSM design exhibited the highest von Mises principal stress, while FSMs with curved arms and surrounding primary mandibular left first molar in the mesial area demonstrated the lowest von Mises stress accumulation. Intense stress accumulation on the distal surface of tooth 74 was observed in the test models due to the transmitted forces by the FSM. The maximum principal stresses accumulated at the base of the alveolar socket of the mesial root of tooth 36, while the minimum principal stresses were identified at the mesio-marginal area of the alveolar crest. The arm design played a crucial role in enabling the appliance to effectively withstand the stresses accumulating on the Space maintainer (SM) and orthodontic band. Bending the SM arms to match the surrounding profile with curvature increased the stress absorption capacity by increasing the arm length.

Distal guide as a substitute for distal shoe space maintainer: a case series study.

Early loss of the primary second molar (DSM) before the eruption of the permanent first molar (PFM) may result in its mesial drift during the eruption. Traditionally, a distal shoe space maintainer is used in this situation to control the path of eruption and preserve the space. However, considering its disadvantages, an alternative appliance needs to be developed for guiding the unerupted PFM. The purpose of this article is to represent an innovative design for preserving space after the early loss of the DSM, describe the fabrication process, and present some data on the successful results of using the appliance in five cases.

Effects of Fixed and Removable Space Maintainers on Dental Plaque and DMFT/dft Values / Efecto de los mantenedores de espacio fijos y removibles en la placa dental y en los valores de los índices DMFT/dft

ABSTRACT: Purpose: Space maintainers are important for the health and placement of children's primary and permanent teeth. However, plaque and caries levels can be negatively affected when a dental appliance is in the mouth. This study aims to evaluate the oral health of pediatric patients that have space maintainers applied as a result of early tooth loss. Methods: This study included 100 systemically healthy patients between the ages of 4-15 years that were treated with space maintainers due to early loss of teeth. Decayed, missing, filled tooth index values and dental plaque status of the participants were recorded. Controls were performed in the 6th and 12th month. The index results were compared and evaluated statistically using ANOVA and paired-t-tests. Results: A total of 116 space maintainers, including 36 band and loops, 16 lingual arches, 21 palatal arches, 43 removable appliances, were evaluated in the study. Statistically significant differences were found between the pre-treatment and post-treatment index values (p<0.001). In the group of band and loops and removable space maintainers; the increases in DMFT/dft values of 6th month and 12th month according to initial DMFT/dft values were statistically significant (p<0.05). For plaque index, the increase in 12th month of all types of appliances were found statistically significant (p<0.001). The greatest increase in plaque index level was seen in the teeth of patients that had been treated with a lingual arch. Conclusions: Incompatible space maintainers can lead to caries, increased plaque accumulation, demineralized areas, and periodontal problems. The accumulation of plaque and difficulty of cleaning the teeth, especially in the fixed space maintainers, negatively affects the health of teeth. For this reason, good oral hygiene should be provided to patients and controls should be regularly performed.

RESUMEN: Los mantenedores de espacio son importantes para la salud y la colocación de la dentición primaria y permanente de los niños. Sin embargo, los niveles de placa y caries pueden verse afectados negativamente cuando se coloca un aparato dental en la boca. Este estudio tiene como objetivo evaluar la salud bucal de pacientes pediátricos a los que se les aplicó mantenedores de espacio como resultado de la pérdida temprana de los dientes. Métodos: Este estudio incluyó a 100 pacientes sistémicamente sanos entre las edades de 4 a 15 años que fueron tratados con mantenedores de espacio debido a la pérdida temprana de dientes. Se anotaron los valores del índice de dientes cariados, faltantes y el estado de la placa dental. Los controles se realizaron en el 6° y 12° mes. Los resultados del índice se compararon y evaluaron estadísticamente mediante ANOVA y pruebas t pareadas. Resultados: Un total de 116 mantenedores de espacio, incluyendo 36 bandas y bucles, 16 arcos linguales, 21 arcos palatinos, 43 dispositivos removibles, fueron evaluados en el estudio. Se encontraron diferencias estadísticamente significativas entre los valores de los índices en el pretratamiento y postratamiento (p<0.001). En el grupo de bandas, bucles y mantenedores de espacio removibles los aumentos en los valores de DMFT/ dft en el sexto mes y el 12º mes fueron estadísticamente significativos (p<0.05). Para el índice de placa, el aumento en el 12º mes de todos los tipos de aparatos se encontró estadísticamente significativo (p<0,001). El mayor aumento en el nivel del índice de placa se observó en los pacientes que habían sido tratados con un arco lingual. Conclusiones: los mantenedores de espacio pueden provocar caries, aumento de la acumulación de placa, áreas desmineralizadas y problemas periodontales. La acumulación de placa y la dificultad de limpiar los dientes, especialmente en los mantenedores de espacio fijos, afecta negativamente la salud dental. Por esta razón, se debe proporcionar una buena higiene bucal a los pacientes y se deben realizar controles regularmente.

Mantenedor de espacio funcional elaborado con corona de NuSmile / Elaborated functional space maintainer with zirconia NuSmile crown

La caries de la infancia temprana, al igual que otras formas de caries, se caracteriza por ser multifactorial, infecciosa y de rápida evolución. Puede presentarse como lesiones cavitadas o no cavitadas, se diagnostica principalmente en menores de seis años en la superficies de los dientes anterosuperiores, debido a que son los primeros órganos dentales en erupcionar y tienen mayor contacto con el estímulo cariogénico. En casos severos pueden llegar a ocasionar la pérdida de órganos dentales, influyendo en la salud general del paciente y repercutiendo en su autoestima y desarrollo psicosocial. Para devolver las características y funciones perdidas en ausencia de algún órgano dental, se recurre a sustituirlo mediante aparatología, mayormente en forma de un mantenedor de espacio funcional. Las necesidades estéticas individuales de cada caso generan diversas alternativas para adaptarnos a la situación del paciente (AU))

Early childhood caries, like other forms of caries, is characterized by being multifactorial, infectious, and rapidly evolving. It can present as cavitated or uncavitated lesions, it is mainly diagnosed in children under six years of age on the surfaces of the anterior superior teeth, because they are the first dental organs to erupt and have greater contact with the cariogenic stimulus. In severe cases they can cause the loss of dental organs, influencing the general health of the patient and impacting on their self-esteem and psychosocial development. In order to restore the lost features and functions in the absence of any dental organ, it is resorted to by means of appliances, mostly in the form of a functional space maintainer. The individual aesthetic needs of each case generate various alternatives to adapt to the patient's situation (AU)

3D Printed Band and Loop Space Maintainer: A Digital Game Changer in Preventive Orthodontics.

Premature loss of primary molars often leads to loss of arch circumference in the primary and mixed dentition. It can lead to malpositioning and even impaction of permanent tooth, if not prevented. Space maintainers in preventive orthodontics, are imperative in maintaining arch integrity. Band and loop space maintainers are indicated whenever there is premature loss of primary molar. The conventional band and loop space maintainer is most routinely fabricated, but poses certain limitations. Three-dimensional (3D) printing in digital dentistry is one of the major developments in dentistry. It replicates the dental cast in the most accurate forms. This allows for supreme precision and minimal human errors. Besides decreasing the laboratory procedures, it has the least chance of failure or breakage. The current case report discusses 3D printing technology for the fabrication of band and loop space maintainer, which can revolutionize preventive orthodontics for children.

Comparative Analysis of Space Maintenance Using Transpalatal Arch and Nance Button.

The aim of this manuscript analyses the efficacy of Transpalatal Arch (TPA) and Nance Button (NB) in maintaining space after the premature loss of upper primary molars. STUDY DESIGN: 54 subjects who needed space maintenance in the upper arch (23 in the TPA group and 31 in the NB group) and had radiographic follow-up until the appliance removal were enrolled in the study. The space loss was obtained from measurements carried out in initial and final radiographs. Type of dental loss and changes in molar relationship were also recorded. RESULTS: The mean of space loss in the TPA group was 1.336mm, while in the NB group was 0.695mm, with no statistically significant differences between the total space loss neither the type of dental loss within the NB or TPA group (p >0.05). CONCLUSIONS: The loss of space in the unilateral second primary molar is higher in the TPA group than in the NB group, with significant statistically differences (p<0.05). It is concluded that the loss of the leeway space using a TPA as a space maintainer is greater than using a NB.

Influência do banda-alça na manutenção de espaço do arco inferior após a perda precoce de molares decíduos: um estudo piloto / Influence of loop band on mandibular arch space maintenance after early loss of deciduous molars: a pilot study

Objetivo: Avaliar a influência do dispositivo banda-alça na perda de espaço após exodontia precoce de molares decíduos inferiores em escolares, em um período de 3 meses. Materiais e métodos: Trata-se de um estudo piloto de ensaio clínico randomizado, com dois grupos paralelos. A amostra incluiu 25 crianças, entre 6 e 9 anos, com indicação clínica e radiográfica de exodontia unilateral de um molar decíduo inferior. Estes foram divididos em Grupo Controle (G1): sem intervenção; e Grupo Intervenção (G2): com instalação de banda-alça. Todos os pacientes foram moldados antes do procedimento de exodontia (T1) e no acompanhamento de 3 meses (T2). Um avaliador cego quanto aos grupos e tempo realizou as medidas estabelecidas nos modelos de gesso. A análise estatística foi realizada por meio dos testes T pareado e T de Student nos casos de distribuição normal dos dados e testes não-paramétricos Wilcoxon e Mann-Whitney para distribuição não normal. Resultados: Todos os participantes foram classificados como Classe I, com overjet de até 3mm e padrão facial mesocéfalo. A maioria (64%) teve o segundo molar decíduo perdido. Após 3 meses, o G1 perdeu, em média, 0,75mm a mais na distância linear do espaço de extração comparado ao G2 (P<0,05). Conclusão: Concluiu-se que, embora os dois grupos apresentaram perda de espaço, o G1 (sem intervenção) apresentou uma perda de espaço maior no período de acompanhamento de 3 meses.

Objective: To evaluate the influence of the band and loop space maintainer on space loss after the early extraction of mandibular primary molars in schoolchildren, over a period of 3 months. Materials and Methods: a pilot study of a randomized clinical trial was carried out, with two parallel groups. The sample included 25 children, aged between 6 and 9 years, with clinical and radiographic indication for unilateral extraction of a mandibular primary molar. The patients were divided into Control Group (G1): with no intervention; and Intervention Group (G2): with the installation of the space maintainer. A dental cast was obtained before the extraction procedure (T1) and at the 3-month followup (T2). An evaluator, blinded to the groups and time, performed the established measures in the dental casts. Statistical analysis was performed using Paired Sample T test and Student's T test in cases of normal data distribution, and nonparametric Wilcoxon and Mann-Whitney tests for non-normal distribution. Results: All participants were classified as Class I, with an overjet of up to 3 mm and a mesocephalic facial pattern. The majority (64%) had a lost second deciduous molar. After 3 months, the G1 lost, on average, 0.75mm more in the linear distance from the extraction space (P<0.05). Conclusion: It was concluded that, although the two groups showed space loss, G1 (without intervention) showed a greater loss of space in the 3-month follow-up period.

Avulsión dental y mantenedor de espacio estético-funcional y correctivo en Odontopediatría / Dental avulsion and esthetic-functional and corrective retainers use in Pediatric Dentistry / Avulsão dentária e mantenedor do espaço estético-funcional e corretivo em Odontopediatria

RESUMEN Se presentó el caso de un niño de 8 años que acudió al Servicio de Estomatología del Policlínico Universitario "Chiqui Gómez Lubián", de Santa Clara, provincia Villa Clara. En el mismo se observó avulsión del incisivo central superior derecho, fractura no complicada de la corona en incisivo central superior izquierdo y una marcada vestibuloversión. Se confeccionó un aparato placa Hawley de acuerdo a las características y necesidades del paciente, con el fin de lograr la recuperación estética, mantener la longitud del arco y corregir la vestibuloversión en el mismo. El aparato permitió obtener un resultado satisfactorio, que ha influido psicológicamente en el paciente al elevar su autoestima y salud bucal.

ABSTRACT A boy of 8 years old was seen in the dental service at the Policlínico Universitario "Chiqui Gómez Lubián", in Santa Clara, Villa Clara. Examination revealed avulsion in the right upper central incisor, uncomplicated crown fracture in left upper central incisor and an improper alignment of the teeth. Taking into account patients´ characteristics and requirements, it was fabricated a Hawley´s retainer in order to achieve a better aesthetic outcome, maintain the length of the dental arch and correct the improper alignment of the teeth. The appliance has achieved a satisfactory outcome, which has had a psychological influence on the patient by improving his self-esteem and oral health.

RESUMO Foi apresentado o caso de um menino de 8 anos que veio ao Serviço de Estomatologia do Policlínico Universitario "Chiqui Gómez Lubián", em Santa Clara, província de Villa Clara. Neste, observou-se avulsão do incisivo central superior direito, fratura não complicada da coroa em incisivo central superior esquerdo e vestibuloversão acentuada. Um dispositivo de placa de Hawley foi confeccionado de acordo com as características e necessidades do paciente, a fim de se obter recuperação estética, manter o comprimento do arco e corrigir a vestibuloversão nele. O dispositivo permitiu obter um resultado satisfatório, o que influenciou psicologicamente o paciente, elevando sua autoestima e saúde bucal.

YouTube as a source of information on space maintainers for parents and patients.

OBJECTIVE: In recent years the social media offers a handy platform for patients who want to receive medical information. The aim of this study is to assess the content of YouTube as an information source on space maintainers and to evaluate the efficiency of videos by parents and patients. METHODS AND FINDINGS: YouTube was searched for information using two keywords 'space maintainer' and 'space maintainers in pediatric dentistry'. Two dentists reviewed the first 200 videos for each search term. After exclusions, 52 videos were included for analysis. Demographics of videos, including the type of source, date of upload, length, viewers' interaction and viewing rate were evaluated. The overall usefulness of videos was scored according to the American Academy of Pediatric Dentistry Guideline based on 9-point scales. The mean usefulness score of evaluated videos was 4,4 ± 1,5 (range 1-8). There was a significant correlation between usefulness and video length (p<0,05). But there was no significant correlation between usefulness and other demographics. Most videos were uploaded by healthcare professionals (51.9%). Videos uploaded by individual users were less useful compared with videos uploaded by healthcare professionals or organizations. Most of the videos (88,5%) used representative images for visualizing. CONCLUSIONS: YouTube videos about space maintainers are useful for parents only to understand and visualize their function. However, it does not provide sufficient information about adverse effects and types of them. Dentists should warn their patients that videos on the internet may contain incorrect and limited information.

A biodegradable gelatin-based nanostructured sponge with space maintenance to enhance long-term osteogenesis in maxillary sinus augmentation.

The search for bone substitutes that are biodegradable, ensure space maintenance, and have osteogenic predictability, is ongoing in the field of sinus augmentation. We thus compared the bone regeneration potential of nanostructured sponges (NS-Sponge) with that of collagen-stabilized inorganic bovine bones (BO-Collagen), gelatin sponges (Gelatin), and blood clots (Cont) in sinus augmentation of rabbits. NS-Sponge was prepared by thermally induced phase separation with porogen leaching techniques. All the materials were non-hemolytic and cytocompatible. The porous and nanofibrous NS-Sponge showed better dimensional stability to support cell growth and osteogenic differentiation. In vivo, the sinus membrane collapsed in Cont and Gelatin, while BO-Collagen and NS-Sponge maintained the elevated height as assessed by come-beam computed tomography. Limited bone regeneration was observed in Cont and Gelatin. In the entire implanted area, histological analysis revealed a higher percentage of new bone area at 4 weeks of BO-Collagen treatment; however, a significantly greater increase in new bone area was observed after 12 weeks of NS-Sponge treatment. The 12-week remnant NS-Sponge material was significantly lower than the 4-week remnant material. Overall, NS-Sponge may be highly recommended for sinus augmentation, as it exhibits numerous advantages, including excellent operability, clear imaging characteristics, space maintenance, biodegradability, and superior osteogenic potential.

Short-term efficacy of vacuum-formed maintainer for deciduous second molar space maintenance in the mixed dentition: A single-centre, randomized controlled clinical trial.

OBJECTIVE: To compare the efficacy of vacuum-formed and banded space maintainers for deciduous second molar space maintenance during the mixed dentition. SETTING AND SAMPLE POPULATION: The study sample comprised thirty children in the mixed dentition (age range, 5.9 to 9.8 years) with early loss of at least one deciduous second molar. METHODS: This was a parallel-group, randomized, active-controlled clinical trial. Patients were randomly allocated to space maintenance performed with vacuum-formed or banded space maintainers with a 1:1 allocation ratio. The main outcome was any change in mesiodistal width of the extraction space. Secondary outcomes included the lingual rolling or axial rotation of the permanent first molar adjacent to the extraction site and extrusion of the antagonist tooth. Dental casts were obtained before appliance installation (T0), after 3 months (T1) and after 6 months (T2). Digital dental casts were measured using Dolphin 3D software. Chi-square, t test or Mann-Whitney and ANOVA or Friedman test were used for intra- and intergroup comparisons (P < .05). RESULTS: Baseline characteristics were similar between groups except for chronological age. Statistically, but not clinically significant space loss (mean, 0.32 mm; SD, ± 0.39) occurred with the vacuum-formed space maintainer only at the first trimester (T0-T1). Lingual rolling and axial rotation of the first permanent molar were not significant, as well as extrusion of the antagonist tooth. CONCLUSIONS: The results of this study suggested that both tested devices were effective in maintaining space after early extraction of the deciduous second molar over a period of 6 months.

Clinical Evaluation of Ghana Shyams TEFF (Telescopically Expanding Fixed Functional) Space Maintainer Versus Conventional Band and Loop Space Maintainer

Abstract Objective: To compare the clinical efficacy of Ghana Shyam's TEFF space maintainer with band and loop space maintainer. Material and Methods: This split-mouth randomized clinical trial was conducted on 20 children (7-9 years), requiring bilateral/contralateral space maintenance therapy. After consent, all the selected children received both space maintainers and were followed up periodically every six months up to two years for clinical assessment according to the evaluation protocol. Instructions and motivation were given to the children. OHI (S) index was recorded before cementation of appliances. The following aspects were analyzed: 1) efficiency and function; 2) dislodgement due to cement loss; 3) breakage at soldered parts; 4) carious or gingival inflammation affecting abutment teeth; 5) distortion of band; 6) being embedded in gingival tissues / gingival slopping; and 7) initial and final S-OHIS scores. Statistical analysis was done using Fisher exact test for survival time and Chi-square test for chewing efficiency. Results: At 24th-month follow-up, 14 Ghana Shyam's TEFF space maintainers and 16 band and loop space maintainers were found to be intact. Conclusion: As both space maintainers demonstrated similar mean survival time Ghana Shyam's TEFF space maintainer with the added advantage of being functional can be recommended as an effective alternative to band and loop in premature loss of primary molar clinical situations.

Avaliação da prevalência da perda precoce de molares decíduos na dentição mista / Assessment of primary molars early loss in mixed dentition prevalence

Objetivo: Avaliar a prevalência da perda precoce de molares decíduos na dentição mista. Método: Foi realizado estudo em crianças na faixa etária dos 6 a 12 anos. A perda do molar decíduo foi considerada precoce, quando essa ocorreu antes do estágio 6 de Nolla (coroa totalmente formada) do sucessor permanente ou um ano antes de sua esfoliação fisiológica. Foram obtidas radiografias periapicais para constatar a presença do sucessor permanente e o nível de formação radicular, bem como a necessidade de colocação de mantenedor de espaço fixo arco lingual ou botão de Nance. Para o estudo da distribuição de frequências da perda dentária precoce em relação ao gênero e dentição, foi utilizado o Teste Qui-quadrado nível de 5% de probabilidade e o teste não paramétrico, Mann-Whitney, para análise estatística adequada. Resultados: Das 315 crianças examinadas 159 (50,47%) eram do gênero masculino e 156 (49,52%) do gênero feminino. Apenas 25 (7,9%) apresentaram perdas múltiplas dentárias na região posterior, sendo 19 na arcada inferior e 6 na arcada superior. Na inferior, houve predominância de perda do primeiro e segundo molares decíduos. Não existiu diferença na associação entre os gêneros das crianças e a ocorrência de perdas múltiplas dentárias (χ² (1) = 0,03, p>0.05). Conclusão: A prevalência de perda prematura de dentes decíduos foi de 7,9% e os dentes mais acometidos foram os primeiros e segundos molares na arcada inferior. Mantenedores de espaço do tipo arco lingual foram instalados em 6 crianças, que permanecerão até que os sucessores permanentes irrompam na cavidade bucal. (AU)

Objective: To assess primary molars early loss in mixed dentition prevalence. Method: A study was carried out in children aged 6 to 12 years. Deciduous molar loss was considered early when it occurred before Nolla stage 6 (full formed crown) of the permanent successor or one year before its physiological exfoliation. Periapical radiographs were obtained to verify the presence of the permanent successor and the level of root formation, as well as the need for placement of fixed space maintainer lingual arch or Nance button. For the study of frequency distribution of early dental loss in relation to gender and dentition, we used the Chi-square test of 5% probability level and the non-parametric Mann-Whitney test for adequate statistical analysis. Results: Of the 315 children examined, 159 (50.47%) were male and 156 (49.52%) were female. Only 25 (7.9%) presented multiple dental losses in the posterior region, 19 in the lower arch and 6 in the upper arch. In the inferior one there was predominance of first and second deciduous molars loss. There was no difference in the association between genders and the occurrence of multiple dental losses (χ² (1) = 0.03, p>0.05). Conclusion: The prevalence of deciduous teeth premature loss was of 7.9% and the most affected teeth were the first and second molars in the lower arch. Lingual arch space holders were installed in 6 children, who will remain with it until the permanent successors erupt into the oral cavity. (AU)

[Space maintenance for the premature loss of the second primary molar].

Space reduction after the premature loss of the second primary molars is one of the important factors affecting the occurrence of malocclusion, often increasing the demand for orthodontic treatment. It has great significance to select and apply appropriate appliances to maintainthe space soon after the premature loss of the second primary molars. The space should be maintained until the adjacent teeth and the successors erupt successfully. This review summarizes the selection and clinical application of the space maintainer for the premature loss of the second primary molars in different periods, to improve dentists' awareness of the importance of space maintainers and to provide advises for clinical choices.

Blood clot stability and bone formation following maxillary sinus membrane elevation and space maintenance by means of immediate implant placement in humans. A computed tomography study.

OBJECTIVE: The present controlled clinical pilot study proposed to assess blood clot contraction and bone neo-formation following maxillary sinus lift (MSL) with immediate implant placement without using grafts using cone beam tomography exams. MATERIALS AND METHODS: Ten implants were placed in ten patients with a residual bone crest height ≥4 and ≤ 7 mm, in maxillary premolars or 1st or 2nd molars regions, using MSL and immediate implant placement without grafts, by means of the lateral window approach. A resorbable membrane (Bio-Gide®, Geistlich, USA) was used to close the window. Computed tomography images were taken after 15 (T1) and 180 (T2) days to assess the rate of blood clot contraction and bone neo-formation. The images were analysed by OsirixMD software. The Shapiro Wilk test was used to verify the normality hypothesis and the data were submitted to Student's paired t-test. RESULTS: The mean of bone clot height in mesial, apical and distal area referred to implant, presented 4.77 mm, 0.77 mm and 5.30 mm respectively. The mean measurements of new bone formation presented 2.95 mm, 0.44 mm and 3.45 mm. The height contraction (coagulum/new bone formation), between T1 and T2, presented 38%, 43% and 35% respectively, with a significant statistical value p < 0.05. The volume measurements at T1 presented a mean volume of 0.90 cm3 sd ± 0.60 cm3 and at T2 a mean volume of 0.75 cm3 sd ± 0.62 cm3, with a significant volume contraction between T1 and T2, p < 0.005. The mean blood clot contraction was 16.52% ± 8.60%. CONCLUSION: The present study demonstrates consistent bone formation around all assessed implants, although with significant contraction of the blood clot. The need for longitudinal studies to establish a long-term prognosis in different modalities of prosthetic rehabilitation of those implants is strongly suggested.

Maintenance of space by innovative three-dimensional-printed band and loop space maintainer.

Preventive orthodontics is an aspect of pediatric dentistry, which requires a unique set of skills and understanding to aid the patient's treatment and properly align teeth. The safest way to prevent future malocclusions from tooth loss is to place a space maintainer (SM), which is advocated to hold the space until the eruption of permanent teeth. SM manufacturing is a laborious process that requires ample communication with the laboratory to properly complete and provide the patient with optimal results. Band and loop SM is mostly indicated for the premature loss of single primary molar, but this appliance has a number of limitations. Digital technology has resulted in decreasing human errors by automating the dental model fabricating process with three-dimensional printing. The current paper provides an insight of the use of this new technology in pediatric dentistry for manufacturing two types of SMs and a case report.