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.

Diferencia en la expresión del ligando de receptor activador para el factor nuclear K B, en tejido tumoral frente a la infección por diferentes patógenos periodontales / Difference in receptor activator of nuclear factor K B expression in tumoral tissue by different periodontal pathogens

La enfermedad periodontal es una de las principales causas de pérdida dentaria. Clínicamente, esta patología, mediada por la desregulación del sistema inmune producto de una disbiosis ocurrida en el surco gingival, inicia con la inflamación de la encía y evoluciona con el daño irreversible de los tejidos que rodean el diente. El hueso alveolar es uno de los tejidos afectados esta patología, esto debido a la activación de osteoclastos por la sobreexpresión de la proteína RANKL en el huésped. El propósito de este trabajo es determinar el nivel de sobreexpresión de RANKL, en un modelo de células tumorales U2OS, frente a la infección con Porphyromonas gingivalis y Prevotella intermedia. Para identificar el nivel de RANKL, se definieron cuatro grupos: Un grupo control, no tratado; Grupo PG, tratado con P. gingivalis; Grupo PI, tratado con P. Intermedia; y un grupo PG+PI, tratado con ambas bacterias. El nivel relativo de la proteína RANKL fue determinado en el sobrenadante y en los extractos celulares de manera independiente, mediante la técnica Western blot. En sobrenadantes, el grupo PG mostró mayores niveles de RANKL comparados con PI (p < 0,05). En extractos celulares los niveles fueron mayores en el grupo PG+PI (p < 0,05). El grupo PI mostró los niveles más bajos de RANKL. La infección polimicrobiana resulta en una mayor expresión de RANKL en células tumorales U2OS, mientras que frente a la infección P. gingivalis, se observó mayor cantidad de RANKL soluble.

SUMMARY: Periodontal disease is one of the main causes of tooth loss. Clinically, this pathology, mediated by the deregulation of the immune system due to a dysbiosis occurred in the gingival sulcus, begins with the inflammation of the gum and evolves with the irreversible damage of the tissues that surround the tooth. Alveolar bone is one of the most affected tissues by this disease, due to the activation of osteoclasts by the upregulation of RANKL in the host. The aim of this study is to determine the increase of RANKL, in a U2OS tumor cells model, inoculated with Porphyromonas gingivalis and Prevotella intermedia. To identify the level of RANKL, four groups were defined: A control group, not treated; PG group, treated with P.gingivalis; PI group, treated with P. intermedia; and a PG+PI group, treated with both bacteria. The relative level of RANKL was determined in the supernatant and cell extracts independently, using the Western blot technique. In supernatants, the PG group showed higher RANKL levels compared to PI (p < 0.05). In cell extracts the levels were higher in the PG+PI group (p < 0.05.). The PI group showed the lowest levels of RANKL.Polymicrobial infection results in a greater expression of of soluble RANKL was observed.

Research progress on anterior alveolar bone changes after orthodontic treatment involving extractions / 口腔疾病防治

@#It has been traditionally believed that a 1:1 cortical bone remodeling/tooth movement ratio has been preserved during orthodontic treatment for tooth movement, with the alveolar bone on the tension side growing and the alveolar bone on the pressure side resorbing to maintain the balance of the alveolar bone. However, recent studies have shown that alveolar bone loss has been found in patients who have undergone orthodontic treatment, suggesting that the alveolar bone does not change as the teeth change over time. Whether the morphology of the alveolar bone will change when the anterior teeth are moved has been the clinical focus. The changes of anterior alveolar bone in patients who have undergone tooth extraction after orthodontic treatment were summerized by literature review in this paper. The results of the review showed that the alveolar bone at the lingual/palatal root-cervical site of the anterior root is more prone to bone loss after extensive movement of the anterior teeth. With the development of imaging technology, CBCT is now more commonly used for analysis instead of two-dimensional images for measurement, as its results are more accurate. However, there are few multifactorial studies in which CBCT has been used to assess the morphological changes in the alveolar bone. The focus of future research is to compare the long-term changes in the anterior alveolar bone of patients of different ages based on three-dimensional imaging, and to study the correlation between different skeletal features, tooth movement patterns and alveolar bone remodeling.

Avaliação da influência do tabagismo no desenvolvimento da periodontite apical em ratos wistar / Evaluation of smoking influence on the development of apical periodontitis in wistar rats

A infecção endodôntica ocorre a após contaminação do tecido pulpar levando à uma colonização bacteriana dos canais radiculares resultando em uma resposta inflamatória dos tecidos periapicais e formação de uma lesão periapical, a periodontite apical (PA). O tabagismo, por sua vez, tem impactos prejudiciais à saúde oral e sistêmica sendo considerado um importante fator de risco para as doenças periodontais. Este trabalho tem por finalidade investigar a influência do tabagismo no desenvolvimento da periodontite apical em ratos. Trinta e dois ratos machos Wistar foram divididos em 4 grupos experimentais (n=8): Controle (sem periodontite apical induzida e sem inalação da fumaça do cigarro); FU (com inalação a fumaça do cigarro); PA (com periodontite apical induzida); FU+PA (com inalação a fumaça do cigarro e periodontite apical induzida). Para a inalar a fumaça do cigarro, grupo de cinco animais permaneceram em uma câmara de tabagismo inalando a fumaça de 10 cigarros por 8 minutos, três vezes ao dia, durante 50 dias. Decorridos 20 dias de inalação de fumaça do cigarro, foi realizada a cirurgia para indução da periodontite apical nos animais do grupo PA e FU+PA, no primeiro molar inferior direto, o qual permaneceu aberto na cavidade bucal por 30 dias. Nesses 30 dias subsequentes da indução da PA, os animais do grupo FU+PA e FU continuaram com a inalação a fumaça do cigarro. No 50º dia, os animais foram eutanasiados e coletados amostras de tecido hematológico para avalição dos níveis séricos de nicotina, cotinina, fosfatase alcalina, cálcio, fósforo, série vermelha e série branca. As hemimandibula removidas foram escaneadas em microtomógrafo para avaliar o volume da destruição óssea e processadas histologicamente para avaliação do perfil inflamatório e expressão das citocinas IL-6, IL-1ß, TNF-α e dos marcadores do metabolismo ósseo RANKL e OPG. Os dados foram tabulados e aplicados os testes estatísticos de Mann-Whitney para os dados não paramétricos e teste t para os dados paramétricos, a um nível de significância de P< 0.05. Com relação a análise histológica o grupo FU+PA apresentou infiltrado inflamatório mais intenso em relação aos demais grupos (P< 0,05). As citocinas pró-inflamatórias IL-6, IL-1ß, TNF-α apresentaram alto padrão de imunomarcação para o grupo FU+PA (P< 0,05). A análise histométrica mostrou maior área de reabsorção óssea no grupo FU+PA, assim como na análise microtomográfica (P< 0,05). As citocinas RANKL esteve mais expressa no grupo FU+PA (P< 0,05) e OPG teve maior expressão no grupo PA (P< 0,05). Na análise hematológica houve um aumento na concentração de hemácias, hemoglobina e leucócitos para o FU+PA (P< 0,05). Os níveis séricos de cálcio foram menores no FU+PA (P> 0,05), a fosfatase alcalina e o cálcio se manteve constante em todos os grupos experimentais (P> 0,05). A concentração sérica de nicotina e cotinina no grupo FU e FU+PA foram compatíveis com fumante humano(AU)

Endodontic infection occurs mainly after pulp tissue contamination by a carious process, leading to bacterial colonization of root canal system and inflammatory response of periapical tissues, followed by formation of apical periodontitis (AP). It is widely known that smoking has harmful impacts on oral and systemic health and is considered a risk factor for periodontal diseases. The objective of this research was to investigate the influence of smoking on the development of AP in rats. Thirty-two male Wistar rats were divided into 4 experimental groups (n = 8): C - Control (no induced AP and no cigarette smoke inhalation); CSI (cigarette smoke inhalation); AP (induced apical periodontitis); CSI + AP (cigarette smoke inhalation and induced apical periodontitis). To inhale cigarette smoke, group with five animals remained in a smoking chamber inhaling smoke from 10 cigarettes for 8 minutes, three times daily, for 50 days. After 20 days of cigarette smoke inhalation, pulp chamber access was performed to induce apical periodontitis in the first mandibular right molar, which remained with pulp chamber exposed to oral cavity for 30 days in animals in the AP and CSI + AP group. During these 30 days after the AP induction, animals in the CSI + AP and CSI group continued to inhale cigarette smoke. On the 50th day, animals were euthanized and blood sample collected to assess serum levels of nicotine, cotinine, alkaline phosphatase, calcium, phosphorus, red series and white series. The hemimandibles were removed and scanned in microtomograph to assess bone volume and histologically processed to assess inflammatory profile and expression of cytokines IL-6, IL-1ß, TNF-α and bone metabolism markers RANKL and OPG. Data were tabulated and statistically analyzed using Mann-Whitney tests for nonparametric data and analysis of variation test for parametric data, with a significance level of P< 0.05. Regarding histological analysis, CSI+AP group showed more intense inflammatory infiltrate compared to other groups (P < 0.05). Histometric analysis showed a larger area of bone resorption in the CSI + AP group, also observed in the microtomographic analysis (P< 0.05). Group CSI+AP had elevated pro-inflammatory cytokines IL-6, IL-1ß, TNF-α expression (P< 0.05). The RANKL cytokines were also more expressed in the CSI+AP group (P< 0.05), while OPG was more expressed in the AP group (P< 0.05). The hematological analysis revealed an increase in the concentration of red blood cells, hemoglobin, and leukocytes for CSI+AP (P< 0.05). Serum calcium levels were lower in CSI+AP (P> 0.05), and alkaline phosphatase and calcium remained constant in all experimental groups (P> 0.05). The serum concentrations of nicotine and cotinine in the CSI and CSI+AP group were compatible with human smokers(AU)

Clinical efficacy of simple taper retentive implants in immediate posterior dental implantation for 5-7 years / 华西口腔医学杂志

OBJECTIVES@#This study aimed to evaluate the long-term clinical efficacy of simple taper retentive implants in the posterior dental area after immediate implantation for 5-7 years.@*METHODS@#Selected from January 2015 to December 2017 in the Fourth Affiliated Hospital of Nanchang University dental clinic line tooth area immediately after the implant prosthesis, a total of 38 patients, 53 implants, were deep into (bone under 2 mm or higher) and the upper structure was repaired. In addition, after the completion of tracking observation of 60-90 months, the implant surrounding bone health was recorded and analyzed.@*RESULTS@#After 5-7 years of follow-up, 1 of the 53 implants failed to fall out, and the implant retention rate was 98.1%. The amount of bone resorption in the proximal and distal margins 5-7 years after implant restoration was (0.16±0.94) mm and (-0.01±1.29) mm, respectively, and the difference in bone height between the proximal and distal margins of the implant and the immediate post-restoration period was not statistically significant (P>0.05). No statistically significant differences were found in the effects of periodontitis, implant site inflammation, and smoking on peri-implant marginal bone resorption (P>0.05).@*CONCLUSIONS@#The single taper-retained implant broadens the indications for immediate implant placement in the posterior region, and its deep sub-osseous placement (≥2 mm below the bone) avoids to a certain extent the disturbance of the implant by external stimuli and the exposure of the cervical abutment of the implant, with the good long-term stability of the marginal bone around the implant.

Mechanism of Zhibai Dihuang decotion in treating postmenopausal osteoporosis / 药学学报

In this study, the ovarian surgery (ovariectomy, OVX) was used to establish the osteoporosis mice model of primary menstruation, in order to evaluate the protective effects and mechanisms of Zhibai Dihuang decotion on postmenopausal osteoporosis (PMOP). The animal experimental protocol has been reviewed and approved by Laboratory Animal Ethics Committee of Jinan University (number: 20210315-03), in compliance with the Institutional Animal Care Guidelines. C57BL/6 mice were divided into five groups, including Sham group, OVX group, low (32 g·kg-1·day-1) and high dose (64 g·kg-1·day-1) of Zhibai Dihuang decotion groups, positive drug group (alendronate, 9.9 mg·kg-1·q3d). After modeling, mice were given medication intervention for 8 weeks, and then femoral and tibial tissues were taken to detect indicators such as bone microstructure, bone resorption, and oxidative stress. The experimental results showed that after Zhibai Dihuang decotion administration, the bone microstructure damage caused by OVX surgery was alleviated, and the relevant parameters bone mineral density (BMD), bone volume/total volume (BV/TV), trabecular number (Tb. N) and connectivity density (Conn. D) both significantly increased. At the same time, the number of TRAP positive osteoclasts decreased significantly, and the levels of proteins and genes related to osteoclast differentiation decreased, indicating that Zhibai Dihuang decoction could inhibit the increased activity of osteoclast caused by OVX. Afterwards, network pharmacology was used to construct the active compound action target network of Zhibai Dihuang decotion, and it was found that the target genes of its active ingredients were closely related to the oxidative stress pathway. Finally, the detection results of oxidative stress levels in bone tissues showed that after treatment with Zhibai Dihuang decotion, the levels of oxidative stress products 4-hydroxynonenal (4-HNE) and malondialdehyde (MDA) in bone tissues of mice significantly decreased, while the levels of antioxidant stress substance L-glutathione (GSH) increased. These above results indicated that Zhibai Dihuang decotion can regulate the level of oxidative stress in the body and inhibit osteoclast activity, which played a therapeutic role in PMOP, as well as provided theoretical basis for the prevention and treatment of PMOP with traditional Chinese medicine.

Autosomal dominant osteopetrosis type Ⅱ: 2 cases report and literature review / 中华内分泌代谢杂志

Osteosclerosis is a rare hereditary bone metabolic disease, characterized by increased bone mass and density caused by bone resorption disorders, and any abnormal mutation involving osteoclast maturation or function will lead to the occurrence of osteopetrosis. Clinically, the prevalence of autosomal dominant osteopetrosis type Ⅱ(ADO-Ⅱ) is higher than that of other types of osteopetrosis, which involves multiple systems such as endocrine, bone, blood, nerve, ear-nose-throat, and oral cavity. Disease progression is insidious and easily overlooked, and there is no standard treatment. This article summarizes the clinical characteristics, examination data, diagnosis and treatment process of the two patients, analyzes multi-system symptoms, pathogenesis and treatment principles of the disease to improve the management of patients with ADO-Ⅱ.

Melatonin attenuates bone resorption induced by acute sleep deprivation in growing rats / 中华内分泌代谢杂志

Objective:To explore the changes of bone turnover markers induced by sleep deprivation (SD) and the effect of melatonin supplementation on the bone turnover status.Methods:Six-week-old Wistar male rats were divided into SD, normal control (NC), and melatonin supplementation (SD+ MT) groups. Acute SD model was established using a modified multi-level bench method. The bone turnover markers, corticosterone, and melatonin in serum as well as Cathepsin K(CTSK) mRNA expression in bone tissue were tested.Results:Acute SD disrupted the balance between bone formation and bone absorption evidenced by rapid decreased serum procollagen type Ⅰ N-terminal propeptide (PⅠNP) levels and increased β cross-linked C-telopeptide of type Ⅰ collagen (β-CTX) levels ( P=0.003) from 24 h to 72 h. The exogenous melatonin treatment decreased β-CTX [(512.4±95.8) ng/mL vs (696.0±76.5) ng/mL, P=0.004] and the osteoclast-related gene CTSK mRNA level after 72 h SD. Conclusions:Acute SD accelerates bone resorption, which could be partially alleviated by melatonin supplementation.

Application of the "three-in-one" bone repair strategy in the treatment of osteoporotic fractures / 中华创伤杂志

Osteoporotic fractures secondary to osteoporosis increase very rapidly in incidence, and have become a major cause of disability and mortality in the elderly population. Currently, there have no standard guidelines for perioperative management, surgery and postoperative rehabilitation, causing multiple complications and poor therapeutic outcome. The authors previously proposed bone repair strategies including active anti-osteoporosis, adequate bone grafting and bone healing acceleration, namely "three-in-one" bone repair strategy. The care steps in osteoporotic fracture surgery inluded perioperative management, operative precaution, and postoperative prevention of secondary fractures. With this in mind, the authors further discussed the detailed application of "three-in-one" bone repair strategy including perioperative active anti-osteoporosis treatment, early rehabilitation training, standardized internal fixation selection, standard bone grafting methods and prevention of secondary complications, so as to promote the standardized treatment of osteoporotic fractures and improve the prognosis.

Association of bone resorption marker β-CTX with hypercalcemia in patients with Graves′ disease / 中国医师杂志

Objective:To explore the association of bone resorption marker β carboxyterminal peptide of collagen Ⅰ (β-CTX) with hypercalcemia in patients with Graves′ disease (GD).Methods:287 patients with GD who were hospitalized in the endocrinology department of Fuyang People′s Hospital from January 2021 to December 2021 were divided into control group ( n=251) and hypercalcemia group ( n=36) according to the corrected blood calcium level. The clinical data and serum β-CTX level of the two groups were compared. Logistic regression model was used to analyze the risk factors of hypercalcemia in GD patients. Pearson correlation was used to analyze the correlation between serum β-CTX level and other indexes. Results:Of the 287 GD patients, 36 were diagnosed as hypercalcemia, and the incidence of hypercalcemia was 12.54%. The levels of free triiodothyronine (FT3), free thyroxine (FT4), blood phosphorus (P) and β-CTX in hypercalcemia group were higher than those in control group, and the total parathyroid hormone (iPTH) in hypercalcemia group were lower than those in control group (all P<0.05). Multivariate Logistic regression analysis showed that FT3 ( OR=1.283, 95% CI: 1.049-1.570, P<0.05), iPTH ( OR=0.924, 95% CI: 0.863-0.989, P<0.05), β-CTX ( OR=2.488, 95% CI: 1.193-5.189, P<0.05) were the influencing factors for hypercalcemia in GD patients. Pearson correlation analysis showed that β-CTX was positively correlated with FT3, FT4, blood calcium, P, alkaline phosphatase (ALP), total procollagen type I amino end terminal peptide (PINP), N-bone-gamma-carboxyglutamic-acid-containing proteins (N-MID) and 25(OH)D, and negatively correlated with iPTH (all P<0.05). Conclusions:β-CTX is highly expressed in the serum of GD patients with hypercalcemia, which is a risk factor for the occurrence of hypercalcemia in GD patients.

Research progress on an autophagy-mediating AMPK pathway involving bone metabolism-related cells that regulate bone homeostasis in periodontitis / 口腔疾病防治

@#Osteoclasts are the only cells responsible for bone resorption in the body, and osteoblasts are the main cells responsible for bone regeneration in the body. Under physiological conditions, these cells maintain a dynamic balance to maintain bone homeostasis. It was widely believed that the imbalance of bone metabolism is mainly affected by the expression of related inflammatory factors. However, with the gradual expansion of related studies in recent years, autophagy has been shown to be closely related to the differentiation, apoptosis and functions of osteoclasts and osteoblasts. AMP-activated protein kinase (AMPK) is an important regulator of energy metabolism in vivo and is involved in the regulation of autophagy and bone homeostasis in bone metabolism-related cells. Periodontitis is a chronic infectious disease, and its typical symptoms are alveolar bone resorption. At present, controlling the level of periodontal inflammation and alveolar bone resorption more effectively in clinical practice remains a challenge. The detection of AMPK and autophagy levels in bone metabolism-related cells shows certain prospects for the clinical prevention and treatment of periodontitis in the future. Therefore, this article reviews the regulation of periodontal inflammation levels and bone homeostasis through cell autophagy related to AMPK-mediated bone metabolism.

Efectos antirresortivos y antimicrobianos de los antiinflamatorios no esteroideos en lesiones periapicales / Antiresorptive and antimicrobial effects of nonsteroidal anti-inflammatory drugs in periapical lesion

Los antiinflamatorios no esteroideos (AINE) son un grupo de fármacos que han sido comúnmente prescritos por sus propiedades antiinflamato- rias, antipiréticas y analgésicas, mismas que se deben a la inhibición de la formación de prostaglandinas. Este mecanismo ha sido ampliamente respaldado en la literatura; sin embargo, en la actualidad poco se co- noce sobre las propiedades adicionales de estos medicamentos como el efecto antirresortivo y antimicrobiano. La función antirresortiva se debe principalmente al bloqueo de la producción de prostaglandinas en específico la PGE2, que posee gran potencial osteoclastogénico, esencial para la aparición de lesiones periapicales; asimismo, la acción antimicrobiana de los AINE está relacionada con la afectación directa de la perpetuación de biopelícula, potencian la acción de los antibióticos, entre otros. Dichos efectos combinados podrían contribuir en la cura- ción de lesiones periapicales. El objetivo de este estudio es recopilar información actualizada sobre estas funciones agregadas de los AINE, con el fin de dar a conocer a los profesionales estos beneficios en la terapéutica de las lesiones periapicales (AU)

Non-steroidal anti-inflammatory (NSAIDs) are a group of drugs that have been commonly prescribed for their anti-inflammatory, antipyretic and analgesic properties, which are due to the inhibition of prostaglandin formation. This mechanism has been widely supported in the literature; however, currently little is known about the additional properties of these drugs such as the antiresorptive and antimicrobial effect. The antiresorptive function is mainly due to the blockage of prostaglandin production, specifically PGE2, which has great osteoclastogenic potential, and is essential for the appearance of periapical lesions; likewise, the antimicrobial action of NSAIDs is related to the fact that they directly affect the perpetuation of biofilms, enhance the action of antibiotics, among others. These combined effects could contribute to the healing of periapical lesions. The aim of this study is to gather updated information on these added functions of NSAIDs, in order to inform professionals about these benefits in the therapy of periapical lesion (AU)

Preservação alveolar e instalação tardia de implante dentário: relato de caso / Alveolar preservation and late dental implant installation: case report / Preservación alveolar e instalación tardía de implante dental: reporte de caso

Introdução. Decorrente do trauma local, durante a exodontia, ou pela falta de estímulos mastigatórios, a ausência dentária promove respostas biológicas que desencadeiam um processo de reabsorção óssea. A preservação óssea alveolar propõe minimizar a reabsorção óssea alveolar, promovendo maior biodisponibilidade óssea para a reabilitação por implantes dentários. Os implantes dentários são uma modalidade terapêutica eficaz para a reabilitação de ausências dentárias. Objetivo. relatar um caso de reabilitação por implante em alvéolo cicatrizado, após preservação alveolar. Relato de caso. Paciente A.L.L., sexo masculino, 23 anos, compareceu à clínica odontológica da UNIBRA. Ao exame físico observou-se ampla destruição coronária do elemento 25 e, ao exame radiográfico notou-se tratamento endodôntico. O tratamento proposto foi a exodontia minimamente traumática, preservação alveolar com matriz de colágeno e instalação de implante dentário em alvéolo cicatrizado. Discussão. Em desdentados, a falta de estímulos mastigatórios, promove um desequilíbrio no turnover ósseo, desencadeando um processo de reabsorção. A preservação alveolar por matriz de colágeno visa minimizar a reabsorção e fornecer maior biodisponibilidade óssea para a reabilitação por implantes. Conclusão. A preservação alveolar com a matriz de colágeno cumpriu com seu objetivo e, a reabilitação por implante dentário em alvéolo cicatrizado é uma modalidade eficaz na reabilitação de pacientes desdentados... (AU)

Introduction. Due to local trauma, during tooth extraction, or the lack of masticatory stimuli, the absence of teeth promotes biological responses that trigger a process of bone resorption. Alveolar bone promotion minimizes alveolar bone resorption, promoting high bone bioavailability for rehabilitation with dental implants. Dental implants are a treatment modality to edentulous. Objective. Report a case of implant rehabilitation in a healed socket after alveolar preservation. Case report. Patient A.L.L., male, 23 years old, attended the UNIBRA dental clinic. On physical examination, a wide coronary destruction of element 25 was observed and, on radiographic examination, endodontic treatment was noted. The proposed treatment was a minimally traumatic tooth extraction, alveolar preservation with collagen matrix and implant placement in healed sockets. Discussion. In edentulous patients, the lack of masticatory stimuli promotes an imbalance in bone turnover, triggering a resorption process. Alveolar preservation by collagen matrix aims to minimize resorption and provide greater bone bioavailability for implant rehabilitation. Conclusion. Alveolar preservation with collagen matrix fulfilled its objective, and rehabilitation by dental implant in a healed socket is an effective modality in the rehabilitation of edentulous patients... (AU)

Introducción. Por traumatismo local, durante la extracción dentaria, o por falta de estímulos masticatorios, la ausencia de dientes promueve respuestas biológicas que desencadenan un proceso de reabsorción ósea. La preservación ósea alveolar propone minimizar la reabsorción ósea alveolar, promoviendo una mayor biodisponibilidad ósea para la rehabilitación mediante implantes dentales. Los implantes dentales son una modalidad terapéutica eficaz para la rehabilitación de dientes perdidos. Objetivo. reportar un caso de rehabilitación con implantes en un alvéolo cicatrizado después de preservación alveolar. Reporte de un caso. Paciente A.L.L., masculino, 23 años, acudió a la clínica odontológica de la UNIBRA. El examen físico reveló destrucción coronaria extensa del elemento 25 y el examen radiográfico reveló tratamiento endodóntico. El tratamiento propuesto fue extracción dental mínimamente traumática, preservación alveolar con matriz de colágeno y colocación de implante dental en alvéolo cicatrizado. Discusión. En pacientes edéntulos, la falta de estímulos masticatorios promueve un desequilibrio en el recambio óseo, desencadenando un proceso de reabsorción. La preservación alveolar mediante matriz de colágeno tiene como objetivo minimizar la reabsorción y proporcionar una mayor biodisponibilidad ósea para la rehabilitación con implantes. Conclusión. La preservación alveolar con matriz de colágeno cumplió su objetivo, y la rehabilitación mediante implante dental en un alvéolo cicatrizado es una modalidad eficaz en la rehabilitación de pacientes edéntulos... (AU)

Factores de riesgo que inciden en la reabsorción condilar posterior a cirugía ortognática. Revisión bibliográfica / Risk factors that affect condylar resorption after orthognathic surgery. Literature reviewRisk factors that affect condylar resorption after orthognathic surgery. Literature review

La reabsorción condilar (RC) después de una cirugía ortognática (CO) es una consecuencia no deseada y en ocasiones con complicaciones irreversibles. El propósito de la investigación fue determinar los factores de riesgo que inciden en la RC posterior a una CO, mediante una revisión bibliográfica. Para lo cual se planteó un estudio exploratorio y documental, se realizó una revisión de literatura de los artículos desde el periodo de 2000 hasta el 2020, sin restricción de idioma, se excluyeron las investigaciones en animales e in vitro, resúmenes de congresos, publicaciones de RC relacionadas por enfermedad sistémica y estudios sobre remodelación condilar sin especificar RC posquirúrgica. La búsqueda de información se efectuó entre julio-agosto del 2021, en las bases de datos de Pubmed, Embase y SciELO, inicialmente fue con los términos de RC, CO, reabsorción condilar progresiva, "RC y CO", reportando 1346 artículos iniciales, después se hizo una selección de los estudios en función de los factores de riesgo, identificando 53 artículos, siguiendo los lineamientos de PRISMA. Se incluyeron 23 artículos, el análisis de los mismos demostró que los principales factores de riesgo implicados en la RC posquirúrgica son el sexo femenino de los pacientes, entre 14 y 58 años, con maloclusión clase Angle II, con ángulos del plano mandibular alto (24º- 50º), expuestos a una cirugía bimaxilar, avance mandibular (AM) mayor a 5 mm en sentido antihorario, utilizar una fijación intermaxilar rígida y que la recaída posquirúrgica se puede relacionar con la RC.

Condylar resorption (CR) after orthognathic surgery (OS) is an undesirable consequence and sometimes with irreversible complications. The purpose of the research was to determine the risk factors that affect CR after OS by means of a literature review. For which an exploratory and documentary study was proposed, a literature review of the articles from 2000 to 2020 was carried out, without language restriction, excluding animal and in vitro research, conference abstracts, CR publications related to systemic disease and studies on condylar remodeling without specifying postoperative CR. The search for information was performed between July-August 2021, in Pubmed, Embase and SciELO databases, initially it was with the terms of CR, OS, progressive condylar resorption, "CR and OS", reporting 1346 initial articles, then a selection of studies was made according to risk factors, identifying 53 articles, following the PRISMA guidelines. Twenty-three articles were included, the analysis of which showed that the main risk factors involved in postoperative CR are the female sex of the patients, between 14 and 58 years old, with Angle II class malocclusion, with high mandibular plane angles (24º - 50º), exposed to bimaxillar surgery, mandibular advancement (MA) greater than 5 mm counterclockwise, use of rigid intermaxillary fixation and that postoperative relapse can be related to CR.

Differential protein expression of osteoclastogenic factors in odontogenic cysts and tumors

Abstract: The osteolytic activity of odontogenic cysts and tumors is directly associated with their growth and aggressiveness. The influence of proteins expressed by epithelial and mesenchymal cells on this biological event differs between indolent cystic lesions, aggressive cystic lesions, and odontogenic tumors. The objective of this study was to compare the immunohistochemical expression of factors that stimulate (receptor activator of nuclear factor kappa-Β ligand - RANKL, cathepsin K - CatK and matrix metallopeptidase 8 - MMP-8) and inhibit (osteoprotegerin - OPG) osteoclastogenesis between dentigerous cyst (DC), glandular odontogenic cyst (GOC), odontogenic keratocyst (OKC), and ameloblastoma (AB). Paraffin-embedded sections of nine DCs, nine GOCs, 20 OKCs, 21 ABs, and four dental follicles (DFs) were subjected to immunohistochemistry. Immunoreactivity was analyzed semiquantitatively and quantitatively in epithelium and connective tissue, respectively. The proteins were immunoexpressed in epithelial and mesenchymal cells of all lesions studied. The expression of RANKL and CatK was higher in OKC, AB, and GOC (p<0.005). Higher expression of OPG was found in DF and DC compared to the other markers (p<0.005). MMP-8 expression was high in GOC and OKC. This study demonstrated the differential expression of factors that inhibit and stimulate bone resorption during the development of DC, GOC, OKC, and AB. Higher expression of RANKL and CatK was observed in more aggressive lesions. OPG appears to be one of the molecules responsible for the slower growth of DC.

The pivotal role of autophagy in bone cells:bone-related cell activity and bone metabolism / 中国组织工程研究

BACKGROUND:The importance of autophagy for maintaining cellular homeostasis and stress response has long been recognized.As a way for cells to selectively clear their damaged organelles to achieve the recycling of cellular components,autophagy has a pivotal role in bone metabolism.OBJECTIVE:To review the role and possible mechanisms of autophagy in regulating bone-related cell activity and function among bone marrow mesenchymal stem cells,osteoblasts,osteocytes,and osteoclasts.METHODS:PubMed was searched for studies related to autophagy using the keywords of "autophagy;bone marrow mesenchymal stem cells;osteoblasts;osteocytes;osteoclasts."RESULTS AND CONCLUSION:We finally included 84 papers.Autophagy plays an important role in bone metabolism.Autophagy is involved in maintaining the balance between mineralization and absorption,and then maintaining bone homeostasis.An appropriate autophagy inducer may also benefit bone remodeling.Abnormal autophagy can lead to disorders of bone balance,leading to diseases such as osteoporosis.We may prevent or treat bone-related diseases by regulating the level of autophagy as its function in maintaining the balance of mineralization and resorption in bone homeostasis.

Research progress on berberine in the prevention and treatment for periodontitis / 口腔疾病防治

@#Berberine is a natural isoquinoline alkaloid extracted from Rhizoma Coptidis and other Chinese herbal medicines. Since berberine has a variety of biological effects, such as bacteriostasis, anti-inflammatory, anti-bone resorption and blood sugar-lowering effects, and is associated with few side effects, studies are increasingly discovering its potential application in the prevention and treatment of periodontitis. This review summarizes the relevant research progress of berberine in the prevention and treatment of periodontitis in recent years, aiming to provide a new strategy for the clinical prevention and treatment of periodontitis. The results of the literature review showed that berberine could prevent the occurrence and development of periodontitis by inhibiting periodontal pathogens, reducing periodontal tissue inflammation and inhibiting alveolar bone resorption. However, the mechanism of periodontitis is complicated, and current research remains limited. In the future, more in vivo and in vitro studies are needed to further explore the mechanism of berberine in inhibiting the occurrence and development of periodontitis, and more large-sample prospective clinical studies should be conducted to confirm the effect of berberine on the prevention and treatment of periodontitis.

Investigating the effect of the Toll-like receptor-4 inhibitor TAK-242 on alveolar bone resorption in severe periodontitis in rats / 口腔疾病防治

Objective@# The goal of this study was to investigate the effect of the Toll-like receptor-4 (TLR-4) inhibitor TAK-242 on bone resorption in severe periodontitis in rats in order to provide an experimental basis for finding new adjuvant treatments for severe periodontitis.@*Methods @# Eighteen three-week-old male Wistar rats were randomly divided into three groups (n=6). One group was the control group, and the other two groups were modelled with severe periodontitis in bilateral maxillary molars ligated with 5-0 silk thread containing P. gingivalis ATCC33277 (periodontitis and TAK-242 groups, respectively). The TAK-242 group was injected with TAK-242 (2 mg/kg) in DMSO every other day through the tail vein from the first day of silk ligation, and the other two groups were injected with DMSO solvent at the same proportion of body weight for 8 consecutive weeks. At the end of the 8th week, rats in the 3 groups were sacrificed, and maxillary specimens were taken. Three-dimensional reconstruction was achieved after micro-CT scanning to measure the distance between the enamel cementum boundary and alveolar crest at specific sites to assess the amount of bone loss. The parameters related to alveolar bone and bone microstructure were analyzed, and the pathological changes of periodontal tissue were observed by hematoxylin-eosin (HE) staining. Alveolar bone resorption was observed by Methyl Green staining, and the distribution of osteoclasts was observed by anti-tartrate acid phosphatase double staining (TRAP).@*Results@#Micro-CT quantitative analysis showed that alveolar bone resorption in the periodontitis group and TAK-242 group was significantly higher than that in the control group. Compared with the periodontitis group, bone loss of the mesial and distal root resorption sites of maxillary first molars was significantly reduced in the TAK-242 group (P < 0.001), the bone mineral density (P < 0.05) and bone volume/total volume fraction (P < 0.01) were significantly increased, and the number of trabeculae and the trabeculae thickness (P < 0.01) were relatively increased. The trabecular separation (P < 0.01) and trabecular structure model index were significantly decreased. In the periodontitis group, the bone exhibited a sparse and porous honeycomb structure, with deterioration of the trabecular structure and a shift towards a rod-strength structure. In the TAK-242 group, the bone microstructure was improved, the bone volume was enriched, the distribution of trabeculae was relatively denser and the trabecular structure shared more similarities with the control group. HE staining displayed that the attachment loss and bone absorption were significantly higher in the periodontitis group and TAK-242 group than in the control group. Compared with the periodontitis group, MG staining displayed significantly alleviated bone absorption in the TAK-242 group. TRAP staining showed that osteoclast infiltration decreased in the TAK-242 group compared with the periodontitis group (P < 0.001)@*Conclusions @#The TLR-4 inhibitor TAK-242 can alleviate bone resorption in severe periodontitis and improve the porous, sparse and disorganized inflammatory bone trabecular structure in rats.

Research progress on the effect of implant-supported overdentures on residual ridges / 口腔疾病防治

@#With the growing maturity of implant technology, implant overdenture has gradually become a conventional repair method for edentulous patients to restore beauty and function, which improves the quality of life of edentulous patients. This paper reviews the effects of implant factors, attachment factors, occlusal factors and patients' own factors on residual alveolar ridge. Existing studies suggest that when designing denture, doctors first need to consider the oral mucosa and jaw conditions of patients before operation, and select the appropriate size of implant to ensure that sufficient bone remains around the implant; Secondly, when choosing the type of attachment, the number, location and A-P distance of implants should be fully considered, and the inclination of cusp should be properly reduced to avoid the harm of excessive lateral force to alveolar ridge; Finally, regular reexamination should be carried out after operation to maintain longer service time of denture and more sufficient bone mass of edentulous patients. However, there are many factors affecting jaw absorption. In the future, we should further explore many factors, such as patients' habit and frequency of wearing dentures, oral health and nutritional status, systemic diseases and medication.

Correlation between proteoglycan and alveolar bone resorption in a mouse periodontitis model / 口腔疾病防治

Objective@#To analyze changes in proteoglycan and its correlation with alveolar bone resorption in periodontitis. @*Methods @#Twelve eight-week-old C57BL/6J male mice were selected, and the periodontitis model was established by ligating the right maxillary second molar with 6-0 silk thread. The nonligated part of the left maxilla was used as the control. The mice were killed 14 days after the operation. Micro-CT was used to assess alveolar bone resorption. HE staining was used to observe the alveolar bone profile, and TRAP staining was conducted to examine the positive rate of osteoclasts. The expression of proteoglycan-related genes, such as aggrecan (ACAN), biglycan (BGN), versican (VCAN), decorin (DCN), osteoclast-related genes, such as cathepsin K (CTSK), matrix metalloprotein-9 (MMP-9), and receptor activator of nuclear factor kappa-B ligand (RANKL), and inflammation-related genes, such as interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α), was detected by real-time quantitative PCR. Additionally, the correlation of the expression of proteoglycans with osteoclast-related genes and inflammation-related genes was evaluated by Pearson correlation analysis.@* Results@#The resorption of alveolar bone on the periodontitis side increased. TRAP staining showed that the number of osteoclasts was substantially increased in the maxilla with periodontitis. Real-time quantitative PCR demonstrated that compared with the control side, the expression of proteoglycan-related genes, such as ACAN, BGN, and DCN, was decreased, whereas the expression of the VCAN gene was significantly increased in the periodontitis side. Meanwhile, the expression of osteoclast-related genes, such as CTSK, MMP-9, and RANKL, and inflammation-related genes, such as IL-1β, IL-6, and TNF-α, was markedly increased in the periodontitis side (P<0.05). Pearson correlation analysis indicated a negative correlation between the expression of proteoglycans and the mRNA levels of osteoclast-related genes and inflammation-related genes (P<0.05). @*Conclusion @#The expression of proteoglycan was closely related to alveolar bone resorption in a periodontitis model.