Partial extraction therapies (PET): a review of the literature / Terapias de extração parcial (TEP): uma revisão da literatura

ABSTRACT One of the most common dental procedures is tooth extraction; however, the bone defect resulting from the process is only partially restored, leading to considerable bone loss. To rehabilitate a fully or partially edentulous patient, we must handle these sites with delicate surgical procedures. There is a large literature presenting attempts to overcome the negative effects of a dental extraction, with the aim of reducing tissue volume loss or restoring the alveolar architecture. In this context, Partial Extraction Therapy (PET) represents a subgroup of interventions to prevent bone loss after extraction using the tooth itself to prevent alveolar bone loss. This literature review aims to make a survey of the published articles on PET, with an emphasis on socket shield technique, and to explain the other techniques such as root burial, pontic-shield and proximal socket-shield, their indications and counter indications in order to deepen the knowledge of these techniques. To identify the included or considered studies, we adopted a detailed search strategy for MEDLINE and Cochrane Library focused in the last 31 years, whose language was English, Spanish or Portuguese. This text presents an analysis of current data regarding the alternatives for alveolar preservation and the installation of immediate implants in these areas, presenting the possibility of a different surgical technique. However, due to the immaturity and lack of conclusive scientific evidence regarding the predictability of the procedures, it is considered that the use of the socket shield technique must be done in an extremely cautious way.

RESUMO Um dos procedimentos odontológicos mais comuns é a extração dentária, contudo, , o defeito ósseo decorrente do processo é apenas parcialmente restaurado, levando a uma perda ossea volumétrica consideravel. Para reabilitar um paciente totalmente ou parcialmente desdentado, devemos manusear estes sitios com intervenções cirúrgicas delicadas. Há uma vasta literatura apresentando tentativas de transpor os efeitos negativos de uma extração dentária, com o objetivo de diminuir a perda volumétrica tecidual ou restaurar a arquitetura alveolar. Neste contexto, a Terapia de Extração Parcial (TEP) representa um subgrupo de intervenções para prevenir a perda óssea após exodontia, usando o próprio dente para prevenir a perda óssea alveolar. Essa revisão de literatura tem por objetivo fazer um levantamento dos artigos publicados sobre as TEP, com ênfase na técnica de socket shield, e explanar a cerca das demais técnicas como sepultamento radicular, pontic-shield e proximal socket-shield, suas indicações e contra-indicações, a fim de aprofundar o conhecimento dessas técnicas. Para a identificação dos estudos inclui?dos ou considerados, adotamos a estrate?gia de busca detalhada para os bancos MEDLINE e Biblioteca Cochrane nos u?ltimos 31 anos, cujo idioma fosse o ingle?s, espanhol ou o portugue?s. Este texto, apresenta uma análise de dados atuais a respeito das alternativas para a preservação alveolar e instalação de implantes imediatos nestas áreas, apresentando a possibilidade de uma técnica cirúrgica diferenciada. No entanto, devido a imaturidade e falta de comprovação cientifica contundente a respeito da previsibilidade dos procedimentos, considera-se que o emprego da técnica de socket shield deve ser feito de forma cautelosa.

Aesthetic effect evaluation of the xenogeneic collagen matrix in keratinized mucosa augmentation around dental implants / 口腔疾病防治

Objective@#To evaluate the stability and aesthetic effect of a xenogeneic collagen matrix (mucograft) on achieving an adequate keratinized mucosa width (KMW) around implants and to provide a reference basis for the clinical application of xenogeneic collagen matrix materials.@*Methods@#The hospital ethics committee approved the study protocol, and the patients provided informed consent. Twenty patients with a KMW<2 mm at the buccal implant site who were treated in Binzhou Medical University Affiliated Yantai Stomatological Hospital from July 2020 to September 2022 were included, and a total of 36 implants were included. The mean age of the patients was (52.0±10.4) years, of which 18 were females and 2 were males. They were divided into a free gingival graft group (FGG, control group) and a xenogeneic collagen matrix group (test group) according to different graft materials. The incremental effect of the KMW on the buccal side of the implant and the mucosal shrinkage rate was measured at 1 month and 3 months after the operation. The mucosal scar index (MSI) was evaluated after the operation.@*Results@#At 3 months postoperatively, the KMW was (3.67 ± 1.06) mm in the control group and (2.96 ± 0.98) mm in the test group, and the difference was statistically significant (t = 2.076, P<0.05). The KMW shrinkage rate was (33.34 ± 16.30) % in the test group and (22.05 ± 15.47) % in the control group at 1 month postoperatively and (51.95 ± 12.60) % in the test group and (37.44 ± 16.30) % in the control group at 3 months postoperatively, with statistically significant differences between the two groups at the same time points (P<0.05). Three months after surgery, the test group showed significantly better outcomes than the control group in terms of the five scar indicators (scar width, scar convexity, scar color, scar trace, and overall appearance), and the difference was statistically significant (P<0.05).@*Conclusion@#Xenogeneic collagen matrix can increase the peri-implant KMW and achieve a more natural and coordinated soft tissue aesthetic effect but with a higher shrinkage rate.

Evaluation of Cardiovascular Parameters of ASA I and ASA II Patients Undergoing Dental Implant Surgery Under Intravenous Sedation with Midazolam: A Retrospective Analysis

The purpose of this research was to compare the vital signs of ASA II patients undergoing dental implant surgery under intravenous anesthesia to those of ASA I patients. From a specialist course in Implant Dentistry, 41 medical records (22 ASA I and 19 ASA II patients) were analyzed. Age, gender, ASA classification, blood pressure, heart rate, and oxygen saturation were all measured. Pre-surgery, following the onset of local anesthetic, at the end of the initial implant insertion, and at the end of surgery were all used to collect vital signs. Student's t-test (p<0.05) was used to determine inter- and intra-group data associations. The crossing of operative moments pre-surgical and installation of the first implant in both systolic (p<=0.01) and diastolic (p<=0.03) pressure was statistically significant in ASA I patients. In contrast, there was only a statistical difference in the verification of peripheral oxygen saturation data at preoperative and local anesthesia times in ASA II patients (p<=0.04). When comparing the time of installation of the first implant (p<=0.03) and at the end of surgery (p<=0.02), with respect to systolic pressure, ASA II presented statistically higher, while variable oxygen saturation at the beginning of local anesthesia in ASA I was statistically higher (p<=0.04). It is proposed that intravenous sedation acts in a compensatory manner in patients with systemic disease, leading both groups' behavior to be similar.

El propósito de esta investigación fue comparar los signos vitales de pacientes ASA II sometidos a cirugía de implante dental bajo anestesia intravenosa con los de pacientes ASA I. Se analizaron 41 historias clínicas de un curso de especialista en Implantología (22 pacientes ASA I y 19 ASA II). Se midieron la edad, el sexo, la clasificación ASA, la presión arterial, la frecuencia cardíaca y la saturación de oxígeno. Se tomarn los signos vitales antes de la cirugía, después del inicio de la anestesia local, al final de la inserción inicial del implante y al final de la cirugía. Se utilizó la prueba t de Student (p<0,05) para determinar las asociaciones de datos entre e intragrupos. El cruce de los momentos operatorios prequirúrgicos y de instalación del primer implante tanto en la presión sistólica (p<=0,01) como en la diastólica (p<=0,03) fue estadísticamente significativo en los pacientes ASA I. En contraste, solo hubo diferencia estadística en la verificación de los datos de saturación periférica de oxígeno en el momento preoperatorio y de anes- tesia local en los pacientes ASA II (p<=0,04). Al comparar el tiempo de instalación del primer implante (p<=0,03) y al final de la cirugía (p<=0,02), con respecto a la presión sistólica, el ASA II se presentó estadísticamente mayor, mientras que la variable saturación de oxígeno al inicio de la anestesia local en El ASA I fue estadísticamente mayor (p<0,4). Se propone que la sedación intravenosa actúa de forma compensatoria en pacientes con enfermedad sistémica, lo que hace que el comportamiento de ambos grupos sea similar.

Rehabilitación implanto protésica en paciente con injerto mandibular de larga data / Implant-prosthetic rehabilitation in a patient with a longstanding mandibular graft / Reabilitação protética com implantes em pacientes com enxerto mandibular de longa data

En la actualidad es cada vez más frecuente la consulta de pacientes que siendo sometidos en edades tempranas a cirugías de extirpación tumoral y posterior reconstrucción con injertos presentan problemas tanto funcionales como estéticos, el uso de prótesis implantosoportadas mejora la calidad de vida, pero al mismo tiempo representan un desafío por la baja disponibilidad ósea. Se presenta un caso clínico de rehabilitación protésica implantosoportada en una paciente con gran déficit óseo mandibular como consecuencia de le extirpación de una neoplasia y posterior injerto de costilla. Se colocaron 2 implantes osteointegrados en hueso remanente y rehabilitación con prótesis removible sostenida a una barra colada. Por ser un tratamiento poco invasivo y conservador fue aceptado fácilmente por la paciente y la mejora tanto en la estética como en la función fue notoria.

Nowadays, it is becoming more and more frequent to see patients who underwent surgery for tumor removal and subsequent reconstruction with grafts at an early age, presenting both functional and esthetic problems. The use of implant-supported prostheses improves the quality of life, but at the same time represents a challenge due to the low availability of bone. A clinical case of implant-supported prosthetic rehabilitation is presented in a patient with a great mandibular bone deficit as a consequence of the removal of a neoplasm and subsequent rib graft. Two osseointegrated implants were placed in the remaining bone and rehabilitation with a removable prosthesis supported by a cast bar. Being a minimally invasive and conservative treatment, it was easily accepted by the patient and the improvement in both esthetics and function was notorious.

Atualmente, são cada vez mais frequentes os pacientes submetidos à cirurgia de remoção de tumores e posterior reconstrução com enxertos em idade precoce que apresentam problemas funcionais e estéticos. O uso de próteses implanto-suportadas melhora a qualidade de vida, mas, ao mesmo tempo, representa um desafio devido à baixa disponibilidade de osso. Apresentamos um caso clínico de reabilitação protética implanto-suportada em um paciente com grande déficit ósseo mandibular em consequência da remoção de uma neoplasia e posterior enxerto de costela. Dois implantes osseointegrados foram colocados no osso remanescente e a reabilitação foi feita com uma prótese removível suportada por uma barra de gesso. Por se tratar de um tratamento minimamente invasivo e conservador, foi facilmente aceito pelo paciente e a melhora na estética e na função foi perceptível.

RADIOGRAPHIC EVALUATION OF THE SUCCESS OF IMPLANT-SUPPORTED TOTAL PROSTHESES ON CONICAL EXTERNAL HEXAGON IMPLANTS AND 6-MONTH FOLLOW-UP AFTER INSTALLATION OF THE PROSTHESES

The development of dental implants has revolutionized the rehabilitation possibilities for partially or totally edentulous patients. The long-term success of the dental implant depends on osseointegration and this is achieved by the combination of two essential stabilities: primary and secondary. Implant-supported prostheses are a great evolution for these treatments, positively interfering in the quality of life of the population, as they generate function and aesthetics for the patient. Thus, the present study aimed to radiographically evaluate complete dentures supported by an external hexagon conical implant in the anterior region of the mandible. More specifically, to evaluate the feasibility of using these implants in cortical bone of the mandible, to verify the success rate regarding the significance of peri-implant bone loss and to compare peri-implant bone loss between patients.

Three-dimensional finite element analysis of cement flow in abutment margin-crown platform switching / 北京大学学报(医学版)

OBJECTIVE@#To analyze the cement flow in the abutment margin-crown platform switching structure by using the three-dimensional finite element analysis, in order to prove that whether the abutment margin-crown platform switching structure can reduce the inflow depth of cement in the implantation adhesive retention.@*METHODS@#By using ANSYS 19.0 software, two models were created, including the one with regular margin and crown (Model one, the traditional group), and the other one with abutment margin-crown platform switching structure (Model two, the platform switching group). Both abutments of the two models were wrapped by gingiva, and the depth of the abutment margins was 1.5 mm submucosal. Two-way fluid structure coupling calculations were produced in two models by using ANSYS 19.0 software. In the two models, the same amount of cement were put between the inner side of the crowns and the abutments. The process of cementing the crown to the abutment was simulated when the crown was 0.6 mm above the abutment. The crown was falling at a constant speed in the whole process spending 0.1 s. Then we observed the cement flow outside the crowns at the time of 0.025 s, 0.05 s, 0.075 s, 0.1 s, and measured the depth of cement over the margins at the time of 0.1 s.@*RESULTS@#At the time of 0 s, 0.025 s, 0.05 s, the cements in the two models were all above the abutment margins. At the time of 0.075 s, in Model one, the gingiva was squeezed by the cement and became deformed, and then a gap was formed between the gingiva and the abutment into which the cement started to flow. In Model two, because of the narrow neck of the crown, the cement flowed out from the gingival as it was pressed by the upward counterforce from the gingival and the abutment margin. At the time of 0.1 s, in Model one, the cement continued to flow deep inside with the gravity force and pressure, and the depth of the cement over the margin was 1 mm. In Model two, the cement continued to flow out from the gingival at the time of 0.075 s, and the depth of the cement over the margin was 0 mm.@*CONCLUSION@#When the abutment was wrapped by the gingiva, the inflow depth of cement in the implantation adhesive retention can be reduced in the abutment margin-crown platform switching structure.

Factors influencing the accuracy of intraoral impression in implant restoration / 口腔疾病防治

@#Due to advances in digital technology, intraoral impressions have been increasingly used to fabricate implant restorations because of its simplicity, high efficiency, comfortableness and convenience. In clinical practice, the accuracy of intraoral impressions depends on various factors, including scanner technique, status of dentition and implants, auxiliary devices, materials and environment, which might influence its accuracy and limit its application. When applied to patients missing more teeth, its accuracy may be insufficient. It is suggested that intraoral impressions be used cautiously when there are multiple and far apart implants and that the scan body not be tightened excessively and that maintain appropriate environmental conditions. In this article, we have reviewed recent relevant literature and the factors affecting the accuracy of intraoral impressions for implant restoration.

"Brain-inspired intelligence" in dental implant decision-making / 口腔疾病防治

@#At present, implant surgery robots have basically achieved "surgical intelligence", but "brain-inspired intelligence" of robots is still in the stage of theory and exploration. The formulation of a clinical implantation plan depends on the timing of implantation, implantation area, bone condition, surgical procedure, patient factors, etc., which need to evaluate the corresponding clinical decision indicators and clinical pathways. Inspired by evidence-based medicine and the potential of big data and deep learning, combined with the data characteristics of clinical decision indicators and clinical pathways that can be quantitatively or qualitatively analyzed, this review simulates the cognitive behavior and neural mechanisms of the human brain and proposes a feasible brain-inspired intelligence scheme by predicting the decision indices and executing clinical pathways intelligently, that is, "select clinical indicators and clarify clinical pathways -- construct database -- use deep learning to intelligently predict decision indicators -- intelligent execution of clinical pathways -- brain-inspired intelligence of implant decision-making". Combined with the previous research results of our team, this review also describes the process of realization of brain-inspired intelligence for immediate implant timing decisions, providing an example of the comprehensive realization of brain-inspired intelligence of implant surgery robots in the future. In the future, how to excavate and summarize other clinical decision factors and select the best way to realize the automatic prediction of evidence-based clinical indicators and pathways and finally realize the complete intellectualization of clinical diagnosis and treatment processes will be one of the directions that dental clinicians need to strive for.

Key points to execute internal horizontal mattress suture in tissue augmentation / 口腔疾病防治

@#Ideal sutures can provide great fixation, wound closure and a stable environment for healing of the surgical site. Tension-free apposition sutures are important for tissue regeneration and could tackle insufficient amounts of soft and hard tissue, especially in missing tooth sites that require implantation. The internal horizontal mattress suture, similar to the conventional horizontal mattress suture, forms a rectangle that can be bisected by the incision with both intrusion and extrusion of the needle on each side. On the basis of the rectangle, the internal horizontal mattress suture emphasizes that the suture should be located below the incision, so the eversion of the wound margin is the highlight of this procedure. The internal horizontal mattress suture could stabilize the graft on the targeting tissue, realize the fixation of the collagen membrane, apically repositioned flap and soft tissue graft, reduce the tension on the incision, and further release the tension of the incision margin. Beyond the primary need for fixation and wound closure, internal horizontal mattress sutures can also achieve stress interruption that reduces the interference of the surrounding muscle and can better master wound tension with the assistance of interrupted sutures. Given the above advantages, horizontal internal mattress sutures have great potential in the application of implant-related regenerative surgery. In this review, according to our experience in clinical practice and the literature, we summarize the advantages of internal horizontal mattress sutures in tissue augmentation. In addition, the sites and sequence to insert the needle and the spatial relationship between the suture and incision are clarified with the rationale of the naming pattern, which is conducive to experience exchange and clinical practice.

Biomechanical analysis of narrow dental implants for maxillary anterior rehabilitation / Análise biomecânica de implantes de diâmetro reduzido para reabilitação da região anterior da maxila

Introdução: O conhecimento da biomecânica de implantes de diâmetro reduzido indica dimensões seguras para uso clínico. Objetivo: O objetivo do presente estudo foi comparar biomecanicamente implantes de diâmetro regular e reduzido para suporte de próteses implantossuportadas unitárias na região anterior da maxila por meio de análise de elementos finitos 3D (3D-FEA). Material e método: Quatro modelos 3D-FEA foram desenvolvidos a partir de recomposição de tomografia computadorizada e dados da literatura: um bloco ósseo na região incisiva lateral superior direita com implante e coroa. M1: 3,75 x 13 mm, M2: 3,75 x 8,5 mm, M3: 2,9 x 13 mm e M4: 2,9 x 8,5 mm. Foi aplicada carga de 178 N nos ângulos 0, 30 e 60 graus em relação ao longo eixo do implante. Foram avaliados mapas de tensão de Von Mises, tensão principal máxima e microdeformação. Resultado: M3 e M4 apresentaram maiores valores de tensão e microdeformação que M1 e M2, principalmente quando foram aplicadas forças inclinadas. Porém, M3 apresentou comportamento biomecânico melhor do que M4. Conclusão: Pode-se concluir que reduzir o diâmetro dos implantes pode prejudicar a biomecânica durante a aplicação de forças, mas a distribuição e intensidade das tensões, bem como os valores de microdeformação podem ser melhorados se o comprimento do implante for aumentado

Introduction: Narrow diameter implants biomechanics knowledge indicates safe dimensions for clinical use. Objective: Purpose of the present study was biomechanically to compare regular and narrow diameter implants to support single implant-supported prosthesis in the anterior region of the maxilla by 3D finite element analysis (3D-FEA). Material and method: Four 3D-FEA models were developed form CT scan recompositing and literature data: a bone block in the right upper lateral incisive region with implant and crown. M1: 3.75 x 13 mm, M2: 3.75 x 8.5 mm, M3: 2.9 x 13 mm and M4: 2.9 x 8.5 mm. It was applied load was of 178 N at 0, 30 and 60 degrees in relation to implant long axis. Von Mises stress, maximum principal stress and microdeformation maps were evaluated. Result: M3 and M4 did show higher tension and higher microdeformation values than M1 and M2, especially when inclined forces were applied. However, M3 presented enhanced biomechanical behavior than M4. Conclusion: It can be concluded that reduce the diameter of the implants can disadvantage to the biomechanics during the application of forces, but the distribution and intensity of the stresses, as well as the micro deformation values can be improved if the length of the implant is increased

Immediate prosthetic rehabilitation of lower molars with hybrid internal tapered implants: report of two cases / Reabilitação protética imediata de molares inferiores com implantes cônicos internos híbridos: relato de dois casos

ABSTRACT The immediate rehabilitation of the posterior region of the mandible with dental implants, expands the set of possible actions for the dental surgeon, in the face of tooth loss. The purpose of this study is to describe two cases of single rehabilitation of mandibular molars with hybrid internal tapered implants indicated for immediate loading in post-extraction socket, associated with the maintenance of the prosthetic and peri-implant space. Implants with macrogeometry and surface treatment (Hydrophilic) were used to optimize primary stability, as well as the type of internal connection and prosthetic abutments that allows better accommodation and healing of adjacent tissues, and protection of the bone graft. Different methodologies of surgical guides did not influence the final result. The predictability of associating techniques and components can be observed in the 2-year follow-up. The initial planning combined with the new technologies enable to achieve stable and functional final restorations.

RESUMO A reabilitação imediata da região posterior da mandíbula com implantes dentários, amplia o conjunto de ações possíveis ao cirurgião dentista, frente as perdas dentárias. O intuito desse estudo é descrever dois casos de reabilitação unitária de molares inferiores com implantes cônicos internos híbridos indicados para carregamento imediato em alvéolos pós-extração, associado a manutenção do espaço protético e peri-implantar. Foram utilizados implantes com macrogeometria e tratamento de superfície que otimizassem a estabilidade primária (Hidrofílicos), bem como o tipo de conexão interna e abutments protéticos que permitisse melhor acomodação e cicatrização dos tecidos adjacentes, e proteção do enxerto ósseo. Diferentes metodologias de guias cirúrgicos não influenciaram o resultado final. A previsibilidade da associação de técnicas e componentes pode ser observada no follow-up de 2 anos. O planejamento inicial aliado às novas tecnologias permite restaurações finais estáveis e funcionais.

Influence of abutment angulation on implant failure in immediately placed and restored implants in the esthetic zone: a randomized clinical trial

Background: Tooth extraction socket in the aesthetic area is a major indication for immediate implant placement greatly improving patient satisfaction and preserving the alveolar ridge. However, the effect of non-axial force on the peri-implant bone with subsequent early implant failure remains unclear. Objective:Evaluate the prognosis of tilted implants immediately placed and restored with angled abutments in comparison to straight implants restored with straight abutments in the esthetic area (anterior or premolars) using computer-aided surgical guides. Material and methods: Badly decayed non-restorable teeth in the aesthetic zone (anterior or premolars) were extracted atraumatically. Immediately after guided implant insertion, the abutments were adjusted and placed according to the allocation group (0, 15, or 25-degree angle) then a temporary crown was performed out of occlusion in centric and eccentric relation. Early implant failure was assessed at three and six months. Results:There was no statistically significant difference between the two groups (P=0.305). Straight and angled abutment groups showed 6 (14.3%) and 8 (20%) failed cases, respectively. The post-hoc subgroup analysis showed no statistically significant difference between angle 15 and angle 25 degree groups where (P=0.686) or between Anterior and Premolar groups (P=0.853). Conclusion: There was no statistically significant difference in the failure rate when comparing angled to straight immediately placed & restored implants. This applies to both anterior and premolar implants

Influence of diameter on mechanical behavior of morse taper narrow implants

Dental implants could give back function, esthetics and quality of life to patients. The correct choice of the implant, especially in borderline cases, is essential for a satisfactory result. Aim: Thus, the objective of this study was to evaluate the mechanical behavior of Morse taper implants with two different prosthetic interfaces. Methods: Twenty self-locking Morse taper implants, 2.9 mm in diameter (FAC), and 20 Morse taper implants, 3.5 mm in diameter (CM) were divided into two groups (n=10), and submitted to strength to failure test, optical microscopic evaluation of fracture, metallographic analysis of the alloy, finite element analysis (FEA) and strain gauge test. A Student's t test (α = 0.05) was made for a statistical analysis. Results: For the strength to failure test, a statistically difference was observed (p <0.001) between FAC (225.0 ± 19.8 N) and CM (397.3 ± 12.5 N). The optical microscopic evaluation demonstrated a fracture pattern that corroborated with FEA ́s results. The metallographic analysis determined that the implants of the FAC group have titanium-aluminum-vanadium alloy in their composition. In the strain gauge test, there was no statistical difference (p = 0.833) between CM (1064.8 ± 575.04 µS) and FAC (1002.2 ± 657.6 µS) groups. Conclusion: Based on the results obtained in this study, ultra-narrow implants (FAC) should ideally be restricted to areas with low masticatory effort

Fatores associados ao interesse de usuários de prótese total mandibular em terapia implantossuportada e impacto da reabilitação com sobredentadura com implante único / Factors associated with the interest of users of complete mandibular dentures in implant-supported therapy and the impact of rehabilitation with single-implant overdentures

Este estudo objetivou identificar os fatores que influenciam na decisão de substituir uma prótese total convencional mandibular pelo tratamento com implantes dentários, assim como avaliar a satisfação, qualidade de vida e performance mastigatória (PM) após reabilitação com sobredentaduras com implante único (SIU) em pacientes adaptados e não-adaptados a prótese total convencional (PT) mandibular. Inicialmente, foi realizado um estudo transversal com 117 usuários de PTs bimaxilares, avaliados quanto aos desfechos relacionados à prótese (número de PTs mandibulares usadas previamente, tempo de uso e profissional que confeccionou a prótese atual, e quanto ao uso regular ou não da prótese mandibular) e aspectos centrados no paciente (período de edentulismo mandibular, altura óssea mandibular e interesse do paciente em se submeter a terapia com implantes). Do total da amostra, 78 pacientes manifestaram interesse na terapia implantossuportada, e desses apenas 22 foram selecionados e reabilitados com novas PTs bimaxilares. Após critérios de elegibilidade, foram alocados após pareamento em 2 grupos: adaptados à prótese mandibular (Grupo PTA - "adaptados à PT mandibular", n:10) e não adaptados (Grupo PTN - "não adaptados à PT mandibular", n:12). Em cada paciente, foi instalado um único implante na linha média e após o período de osseointegração as próteses mandibulares foram convertidas em sobredentaduras. O desempenho mastigatório foi avaliado pelo método das tamises, a altura óssea mandibular por medição em radiografia panorâmica, satisfação por escala quantitativa com questionário validado e o impacto da saúde oral na qualidade de vida pelo questionário OHIP-Edent-19. O teste Qui-quadrado foi utilizado para análise dos dados e as razões de prevalência ajustadas por meio da regressão multivariada de Poisson no primeiro estudo; para o segundo, a análise estatística em cada grupo e entre grupos foi baseada nos testes não-paramétricos de Wilcoxon e Mann-Whitney. O intervalo de confiança para os testes foi de 95%. A amostra foi predominantemente do sexo feminino, com 66,7% (n=78) dos participantes interessados em PT mandibular implantossuportada e com idade média de 65,68±6,38 anos. A PM não influenciou a escolha pela reabilitação com implantes. A preferência pela PT implantossuportada mandibular foi associada significativamente com maior experiência prévia com PT mandibular (p=0,021) e à insatisfação quanto à retenção (p=0,005). Após a intervenção com implante, todos os pacientes não adaptados passaram a condição de adaptados. Não houve diferença entre PTA e PTN para OHIP-Edent (p=0,276) e PM (p=0,222), a satisfação foi significativa apenas para o critério "conforto em arco inferior" (p=0,043). Para comparações pré e pós-tratamento com sobredentadura, a mediana do OHIP-Edent total diminuiu significativamente em ambos os grupos. Na comparação intragrupo, essa redução foi significativa em PTA apenas para a "limitação funcional" (p=0,026), e em PTN em quase todos os domínios, exceto "disfunção social" e "incapacidade" (p>0,05). Houve aumento estatisticamente significativo para a satisfação geral de 75,41 para 90,25 (p=0,012) em PTN e de 76,10 para 90,50 (p=0,007) em PTA. Os parâmetros "mastigação", "adaptação", "retenção" e "conforto" em arco inferior foram diferentes com significância em ambos os grupos, e "gustação", "fonação" e "dor" em arco inferior foram significativos apenas para o grupo não adaptado (p<0,05). Houve diferença significativa para PM em PTN (p=0,002) e PTA (p=0,047) ao se comparar tipo de reabilitação. Não houve correlação entre PM e OHIP antes e após a reabilitação (p>0,05). Pode-se concluir que a experiência prévia com PT mandibulares convencionais e a insatisfação com a retenção dessas, influenciam o interesse pela reabilitação com sobredentadura implantossuportada mandibular, assim como, a reabilitação com sobredentadura sobre implante único apresenta-se como alternativa aos pacientes não adaptados a PT convencional mandibular, auxiliando na aceitação do uso da prótese mandibular, assim como, comprovando efeito positivo na satisfação, qualidade de vida e performance mastigatória (AU).

This study aimed to identify the factors that influence the decision to replace a conventional mandibular complete denture by treatment with dental implants, as well as to evaluate satisfaction, quality of life and masticatory performance (MP) after rehabilitation with overdentures with a single implant in patients adapted and not adapted to conventional mandibular complete denture (CD). Initially, a cross-sectional study was carried out with 117 users of bimaxillaries CDs, who were evaluated for outcomes related to the denture (number of previous mandibular CDs, time of use and professional who made the current denture, and regarding regular use of the mandibular denture) and aspects centered patients (period of mandibular edentulism, mandibular bone height and the patient's willingness to undergo implant therapy). From the total sample, 78 patients expressed interest in implant-supported therapy, and of these, only 22 were selected and rehabilitated with new bimaxillary CDs. After eligibility criteria, they were allocated after pairing into 2 groups: adapted to mandibular prosthesis (PTA Group - "adapted to mandibular CD", n:10) and non-adapted (PTN Group - " not adapted to mandibular CD", n:12). In each patient, a single implant was installed in the midline and after the osseointegration period, the mandibular prostheses were converted into overdentures. Masticatory performance was evaluated by the sieve method, mandibular bone height by paranoid radiographic measurement, satisfaction by quantitative scale with a validated questionnaire and the impact of oral health on quality of life by the OHIP-Edent-19 questionnaire. The chi-square test was used for data analysis and the prevalence ratios adjusted by means of multivariate Poisson regression in the first study; on the second, the statistical analysis in each group and between groups was based on the non-parametric-Wilcoxon and Mann-Whitney tests. The confidence interval for the tests was 95%. The sample was composed predominantly by women, with 66.7% (n=78) of the participants interested in implantsupported mandibular CD, with mean age 65.68±6.38 years. MP was not influenced by the choice by dental implants rehabilitation. Preference for mandibular implant-supported CD was significantly associated with longer previous experience in mandibular CD (p=0.021) and with dissatisfaction regarding retention (p=0.005). After the implant intervention, all non-adapted patients became adapted. There was no difference between PTA and PTN for OHIP-Edent (p=0.276) and MP (p=0.222), satisfaction was significant only for the criteria "comfort in the lower arch" (p=0.043). For pre- and post-treatment comparisons with overdentures, the median total OHIP-Edent decreased significantly in both groups. In the intragroup comparison, this reduction was significant in PTA only for "functional limitation" (p=0.026), and in PTN in almost all domains, except "social dysfunction" and "disability" (p>0.05). There was a statistically significant increase in overall satisfaction from 75.41 to 90.25 (p=0.012) in PTN and from 76.10 to 90.50 (p=0.007) in PTA. The parameters "chewing", "adaptation", "retention" and "comfort" in the lower arch were significantly different in both groups, and "gustation", "phonation" and "pain" in the lower arch were significant only for the group not adapted (p<0.05). There was a significant difference for MP in PTN (p=0.002) and PTA (p=0.047) when comparing the type of rehabilitation. There was no correlation between MP and OHIP before and after rehabilitation (p>0.05). It can be concluded that the previous experience with conventional mandibular CD and the dissatisfaction with the retention of these, influence the rehabilitation with mandibular implant-supported overdenture, as well as the rehabilitation with overdenture on single implant presents itself as an alternative for patients not adapted to mandibular conventional CD, helping to accept the use of mandibular prosthesis, as well as proving a positive effect on satisfaction, quality of life and masticatory performance (AU).

Vertical bone augmentation with guided bone regeneration: a scoping review / Aumento óseo vertical con regeneración ósea guiada: scoping review

Introduction: There are multiple techniques for vertical bone augmentation. Guided bone regeneration is one of them; however, the literature is diverse and includes different study designs, which makes it difficult to synthesize results. Objective: To analyze the general technical characteristics, clinical results, and complications of vertical bone augmentation performed with guided bone regeneration in humans. Material and Methods: This scoping review was based on the PRISMA-ScR guidelines. A search was performed in the Pubmed, Scielo, and Worldcat databases. Papers published from 1990 to April 2020 were included in the study. Research articles not conducted in humans or published in languages other than English and Spanish were excluded. Title and abstract were screened by two reviewers, then full studies were extracted, and data tabulated. Results: 89 studies were included. The highest percentage reported having obtained a vertical bone increase of less than 5 mm and having used non-resorbable membranes. The most frequent type of graft is autogenous and combinations of grafts, the most common being autogenous with xenograft. All studies that reported bone stability of implants in regenerated bone were favorable, as was implant survival, reporting values between 83.8% and 100%. Membrane exposure is the most frequently reported complication, followed by infection or abscesses, and tissue dehiscence. Conclusion: Vertical bone regeneration is a reliable technique, with high predictability and low incidence of complications compared to other vertical bone augmentation techniques.

Introducción: Existen múltiples técnicas para el aumento óseo vertical siendo una opción la regeneración ósea guiada, sin embargo, la literatura es diversa y con distintos diseños que dificultan la síntesis de resultados. Objetivo: Analizar las características generales técnicas, resultados clínicos y complicaciones del aumento óseo vertical realizado con regeneración ósea guiada en humanos. Material y Métodos: Esta revisión de alcance se basó en la guía PRISMA-ScR. Se realizó una búsqueda en las bases de datos Pubmed, Scielo y Worldcat. Fueron incluidos aquellos publicados desde el año 1990 hasta abril de 2020. Se excluyeron los estudios no realizados en humanos o publicados en idiomas distintos al inglés y español. Dos revisores examinaron título y resumen, luego los estudios completos se extrajeron y se ordenaron los datos en tablas. Resultados: 89 estudios fueron incluidos. El mayor porcentaje reportó haber obtenido un aumento óseo vertical menor a 5 mm y haber utilizado membranas no reabsorbibles. El tipo de injerto que más frecuente es el autógeno y las combinaciones de injertos, siendo el más común autógeno con xenoinjerto. Todos los estudios que reportaron estabilidad ósea de implantes en hueso regenerado fueron favorables, al igual que la supervivencia de implantes, reportando valores entre 83,8% y 100%. La exposición de membrana es la complicación que más se repite en los estudios, seguido por infección o abscesos y dehiscencia de tejidos. Conclusión: La regeneración ósea vertical es una técnica confiable, con alta predictibilidad y baja incidencia de complicaciones en comparación a otras técnicas de aumento óseo vertical.

Changes of gingival thickness, gingival papilla and marginal bone resorption in patients with chronic local periodontitis after single implant restoration / 中国基层医药

Objective:To investigate the functional and structural recovery of posterior teeth in patients with chronic local periodontitis after single implant restoration.Methods:A total of 133 patients with tooth loss who need single posterior tooth fixation and implantation in Shaoxing People's Hospital from January to December 2019 were included in this study. These patients were divided into periodontitis ( n = 40) and periodontitis-free ( n = 93) groups according to whether they had chronic local periodontitis. All patients were followed up for 6 months. Probing depth (PD), gingival thickness, papilla index score (PIS), modified sulcus bleeding index (mSBI) and marginal bone resorption were compared between the two groups at 1, 3 and 6 months after implant repair. The success rate of tooth implant was compared between the two groups. Results:There was no significant difference in success rate of tooth implant between periodontitis and periodontitis-free groups [100.0% (93/93) vs. 95.0% (38/40), χ2 = 1.94, P = 0.163]. There was no significant difference in the incidence of postoperative complications between periodontitis and periodontitis-free groups [0.0% (0/93) vs. 2.5% (1/40), χ2 = 0.19, P = 0.663]. In the periodontitis group, PD was significantly greater at 3 and 6 months after surgery than that at 1 month after surgery ( t = 2.31, 4.30, P = 0.020, < 0.001). In the periodontitis group, mSBI was lower at 6 months after surgery than that at 1 month after surgery ( t = 1.97, P = 0.048). In the periodontitis-free group, mSBI was lower at 3 and 6 months after surgery than that at 1 month after surgery ( t = 3.64, 4.50, both P < 0.001). There were significant differences in PD and mSBI between periodontitis and periodontitis-free groups at 6 months after surgery ( t = 2.06, 2.13, P = 0.041, 0.035). At 6 months after surgery, marginal bone resorption in both periodontitis and periodontitis-free groups improved compared with that immediately after surgery. In the periodontitis group, marginal bone resorption at 1 month after surgery was not significantly different from that at 3 and 6 months after surgery ( t = 1.64, 0.63, P = 0.100, 0.524). In the periodontitis-free group, marginal bone resorption at 1 month after surgery was not significantly different from that at 3 and 6 months after surgery ( t = 1.70, 1.18, P = 0.088, 0.236). In the periodontitis group, gingival thickness at 1 month after surgery was not significantly different from that at 3 and 6 months after surgery ( t = 0.99, 0.49, P = 0.321, 0.620). In the periodontitis-free group, gingival thickness at 1 month after surgery was not significantly different from that at 3 and 6 months after surgery ( t = 0.87, 1.36 P = 0.379, 0.173). Gingival thickness and marginal bone resorption at 1 month after surgery were not significantly different from those at 3 and 6 months after surgery in each group ( t = 0.49, 0.39, 0.54, 0.77, 0.55, 0.38, P = 0.623, 0.693, 0.590, 0.439, 0.580, 0.699). Conclusion:Single implant restoration exhibits good short-term effects on tooth loss combined with chronic local periodontitis. Single implant restoration does not have a great impact on gingival thickness and marginal bone absorption, but it leads to a higher incidence of peri-implantitis in patients with periodontitis than in patients with healthy periodontal tissue.

Research progress of superhydrophilic implants / 中国基层医药

In the past few decades, some studies reported that changing the specific surface properties of titanium implants, such as surface morphology, surface chemistry, surface charge and wettability, improved the bone bonding ability of titanium implants. Based on the existing evidence, this review paper analyzes the methods and characteristics of surface chemical modification of the superhydrophilic implants (Thommen INICELL?) that were listed in China in recent years, and clarifies the process of early osseointegration from the viewpoint of histomorphology, and evaluates its clinical application effects.

Transcrestal sinus lift with simultaneous implant placement using osseodensification in posterior maxilla with residual bone height of 4-6 mm / Elevação de seio maxilar via crista do rebordo com instalação simultânea de implante utilizando osseodensificador em região posterior de maxila com altura do remanescente ósseo de 4 a 6 mm

Objective: The aim of this study was to evaluate the transcrestal sinus lift using Osseodensification technique with simultaneous implant placement. Material and Methods: In this case series 7 patients who needed implant placement in the atrophic posterior maxilla were enrolled. In all the cases the residual bone height between the sinus floor and the alveolar crest was 4-6 mm. Transcrestal sinus lift was performed using Osseodensification with simultaneous implant placement. Cone-beam computed tomography (CBCT) were obtained immediately postoperative and 6 months after operation. Implant stability using Osstell® were assessed at the time of implant placement and implant exposure (6 months). Results: The results showed that the mean bone height gain was 5.33±0.83mm at 6 months postoperatively. Mean bone density value was 818.43±109.63 HU. Mean ISQ value was 80.00±3.11 at 6 months postoperatively. The duration of surgical procedure (minutes) ranged between 25-38 minutes with an average of 30.86±4.10 minutes. Conclusion: The crestal maxillary sinus floor elevation using Osseodensification technique with simultaneous implant placement provide superior results regarding bone density and implant stability and less duration of surgical procedure. (AU)

Objetivo: O objetivo deste estudo foi avaliar a elevação de seio maxilar via crista do rebordo com a técnica de Osseodensificação com instalação simultânea de implante. Material e Métodos: Nesta série de casos, participaram 7 pacientes que necessitavam de implantes em região posterior de maxila atrófica. Em todos os casos a altura de remanescente ósseo entre o soalho do seio e a crista alveolar estava entre 4 a 6 mm. A elevação de seio maxilar via crista do rebordo foi realizada com osseodensificação com instalação simultânea de implante. As Tomografias Computadorizadas Cone Beam (TCCB) foram obtidas imediatamente após a cirurgia e 6 meses depois. A estabilidade dos implantes utilizando Osstell® foi avaliada no momento da instalação do implante e no momento da reabertura (6 meses). Resultados: Os resultados mostraram que a média de ganho de altura óssea foi de 5.33±0.83mm após 6 meses da cirurgia. A média da densidade óssea foi de 818.43±109.63 HU. A média de ISQ foi de 80.00±3.11 após 6 meses da cirurgia. A duração do procedimento cirúrgico (minutos) foi entre 25 a 38 minutos com uma média de 30.86±4.10 minutos. Conclusão: A elevação do soalho de seio maxilar via crista do rebordo com instalação simultânea de implante utilizando osseodensificador promove resultados superiores em relação à densidade óssea, estabilidade do implante e menor duração do tempo cirúrgico (AU)

Biomechanical behavior of implants with prosthetic connection of the morse (Cone) type, with different angulations at the implant-abutment interface in multiple dental prostheses: a finite element study / Comportamento biomecânico de implantes com conexão protética tipo morse (cônica), com diferentes angulações na interface implante-pilar em próteses múltiplas: estudo de elementos finitos

ABSTRACT Objective: Evaluate the biomechanical behavior of the influence of different internal angles of conical prosthetic connections in fixed partial prostheses of three elements, through the tridimensional finite element method. Methods: Two different models of segment of the posterior portion of the mandible, with two implants with conical connections at angulations of 11.5 and 16 degrees. Afterwards, and occlusal load of 180N was used, and divided into 2 points of application on the premolar, and 400N divided into 5 points of application on the molar. Data were acquired as the tensile, compressive and shear stresses on cortical and medullary bone, and von Mises stresses on implants and prosthetic components of two implants in both in three-unit fixed partial prosthesis. In the quantitative analysis, both in cortical and medullary bone, the tension peaks in tensile, compression, and shear forces were higher for the CM16 group. Results: When analyzing qualitatively, the cortical and medullary bones presented a greater stress around the implant platform with a higher incidence in the implant in the molar region. In the von Misses analysis in both groups, the tensions were concentrated in the cervical region of the implants, in the first threads, in the premolar and molar regions. Regarding prosthetic pillars, the stress concentration was located in the region of contact with the implant. Conclusion: The increased angulation of conicity of the internal conical connections represents a determinant factor to increase in stress concentration in the implants, prosthetic components and adjacent structures, such as the cortical and medullary bone.

RESUMO Objetivo: Avaliar a influência das diferentes angulações internas de conexões protéticas cônicas em próteses parciais fixas de três elementos, em relação a distribuição de tensões no osso cortical e medular adjacente, também como nos implantes e componentes protéticos através do método dos elementos finitos. Métodos: Foram analisados de forma quantitativa e qualitativa, através do método de elementos finitos, as tensões de tração, compressão e cisalhamento no osso cortical e medular, e tensões de von Misses nos implantes e componentes protéticos de dois implantes, um com conexão cônica de 11.5 graus e o outro de 16 graus. Ambos em prótese múltipla de três elementos. Resultados: Na análise quantitativa, tanto no osso cortical quanto no medular, os picos de tensão nas forças de tração, compressão, e de cisalhamento foram maiores para o grupo CM16, se comparado ao CM11,5, exceto a força de cisalhamento do osso cortical, que obteve valores muito próximos em ambos os grupos. Ao se analisar qualitativamente, os ossos corticais e medulares apresentaram um maior stress ao redor da plataforma dos implantes com incidência maior no implante na região do molar. Na análise von Misses em ambos os grupos, as tensões concentraram-se na região cervical dos implantes, nas primeiras roscas, nas regiões de pré-molar e molar. No que diz respeito aos pilares protéticos, a concentração de tensões foi localizada na região de contato com o implante. Conclusão: Podemos concluir que conforme o ângulo da interface implante-pilar aumenta, ocorre uma incidência maior de tensões em todas as áreas envolvidas nesse estudo.

Does the Use of Surface Electromyography Could Improve Quality of Life among Patients Rehabilitated by Mandibular Overdentures on Different Attachments?

Abstract Objective: To analyze and compare changes of quality of life parameter among dental patients rehabilitated by the implant-supported overdentures with different attachment systems. Material and Methods: Forty-eight patients were recruited as a study cohort. The implant placement procedure was based on the results obtained by CBCT scanning and individualized surgical templates manufactured for correct implant placement. Each individual received two k3Pro Implants (Sure Type with 4.0 or 4.5 mm in diameter) at the intraforaminal area due to standard protocol of implantation provided by the manufacturer under local anesthesia. All patients were distributed between two groups based on the fact of using either Locator- or ball-attachments. Rank correlation was measured using Spearman correlation coefficient, while linear correlation was evaluated by Pearson correlation coefficient. Results: No statistically meaningful differences were noted regarding patients' distribution among groups considering age (p>0.05) and gender (p>0.05). Provided patient-level analysis demonstrated that increase of conventional full denture service time was positively correlated with escalation of OHIP-EDENT scores. The most prominent inter-correspondences were noted specifically between longevity of denture service and elevation of scores within "Functional limitation" (r=0.61; p<0.05), "Physical pain" (r=0.51; p<0.05) and "Physical disability" (r=0.57; p<0.05) subdomains. No statistically argumented regressions were noted between increase tendency of OHIP-EDENT scores and gender (p>0.05) or age (p>0.05) parameters. Conclusion: Significant improvements of quality of life measured with OHIP-EDENT were noted for both types of attachments compared to the pre-treatment situation independently of additionally provided surface electromyography-based alignment.