牙龈生物学类型对上颌单牙种植后龈乳头美学效果的影响

目的 评估牙龈生物学类型对上颌前牙区单牙种植修复后龈乳头美学效果的影响.方法 32例上颌前牙区单牙缺失的患者,按软组织厚度分组,Ⅰ组：16例,厚度1.5 mm～3 mm;Ⅱ组：16例,厚度3.1 mm～4.5mm.共植入32枚ITI种植体,术后2～3个月常规修复,于修复完成当日（基线期）和6个月后（随访期）,应用龈乳头充填指数（PFI）评估种植体周围龈乳头形态.比较基线期和随访期各组PFI变化,并进行统计学检验.结果 观察期内两组均无种植体松动脱落.两组在随访期的PFI均显著高于基线期（P＜0.05）,Ⅱ组在基线期的PFI显著高于Ⅰ组（P＜0.05）,两组之间的PFI变化有显著性差异（P＜0.05）.结论 牙龈生物学类型是影响种植修复后龈乳头美学的重要因素,软组织较厚者龈乳头美学效果更好.     

腭侧结缔组织瓣与脱细胞真皮基质移植扩增种植体唇侧组织的效果比较

目的:比较腭黏膜下结缔组织瓣和异体脱细胞真皮基质(ADM)移植丰满种植区唇侧软组织的效果。方法:22例上前牙区单牙缺失患者,伴缺牙区唇侧牙槽外形凹陷。其中12例行牙种植术同期腭黏膜下结缔组织瓣移植术,10例行牙种植术同期种植区唇侧骨膜下ADM膜覆盖。分别于种植术前,术后2周、3个月、6个月、12个月通过石膏模型分析2组种植区牙槽嵴水平宽度的变化。采用SAS6.12软件包对2组实验数据进行t检验,以确定不同时期2组结果是否有显著性差异。结果:随访期内,2组种植体存留率为100%,种植术后2周及术后3、6、12个月腭黏膜下结缔组织瓣移植组及ADM移植组的牙槽嵴宽度较种植术前均有显著差异(P<0.05);术后各时间段2组牙槽嵴水平宽度扩增量无显著性差异(P>0.05)。结论:腭侧黏膜下结缔组织瓣移植、ADM膜骨膜下移植均能明显改善种植区唇侧丰满度,且扩增水平相近。     

From porcelain-fused-to-metal to zirconia: Clinical and experimental considerations

Objective

The interest of dental research in metal-free restorations has been rising in the last 20 years following the introduction of innovative all-ceramic materials in the daily practice. In particular, high strength ceramics and related CAD/CAM techniques have widely increased the clinical indications of metal-free prostheses, showing more favourable mechanical characteristics compared to the early ceramic materials.The purpose of the present paper is providing a brief review on the all-ceramic dental materials, evaluating pros and cons in the light of the most recent scientific results and of the authors’ clinical experience.

Materials

A structured review of the literature was given on the basis of medical and engineering papers published in the last decades on the use of dental ceramics and zirconia in particular. The experimental and clinical findings of the most relevant researches were reported.

Results

Zirconia is one of the most promising restorative materials, because it yields very favourable mechanical properties and reasonable esthetic. Several in vitro and in vivo investigations reported suitable strength and mechanical performances of zirconia, compatible with clinical serviceability as a framework material for both single crowns and short-span fixed partial dentures. However, clinical results are not comparable, at the moment, with conventional metal-ceramic restorations, neither is there sufficient long-term data for validating the clinical potential of zirconia in the long run.

Significance

The use of zirconia frameworks for long-span fixed partial dentures or for implant-supported restorations is currently under evaluation and further in vivo, long-term clinical studies will be needed to provide scientific evidence for drawing solid guidelines.     

Temporal sequence of hard and soft tissue healing around titanium dental implants

The objective of the present review was to summarize the evidence available on the temporal sequence of hard and soft tissue healing around titanium dental implants in animal models and in humans. A search was undertaken to find animal and human studies reporting on the temporal dynamics of hard and soft tissue integration of titanium dental implants. Moreover, the influence of implant surface roughness and chemistry on the molecular mechanisms associated with osseointegration was also investigated. The findings indicated that the integration of titanium dental implants into hard and soft tissue represents the result of a complex cascade of biological events initiated by the surgical intervention. Implant placement into alveolar bone induces a cascade of healing events starting with clot formation and continuing with the maturation of bone in contact with the implant surface. From a genetic point of view, osseointegration is associated with a decrease in inflammation and an increase in osteogenesis‐, angiogenesis‐ and neurogenesis‐associated gene expression during the early stages of wound healing. The attachment and maturation of the soft tissue complex (i.e. epithelium and connective tissue) to implants becomes established 6–8 weeks following surgery. Based on the findings of the present review it can be concluded that improved understanding of the mechanisms associated with osseointegration will provide leads and targets for strategies aimed at enhancing the clinical performance of titanium dental implants.     

Impact of Gingival Margin Asymmetries on the Smile Esthetic Perception of Dental Specialists,Doctors of Dental Medicine,Students, and Laypeople: a Comparative Pilot Study

ObjectiveTo evaluate the perceptions of altered incisor gingival position among dental specialists, dentists, dental students, and laypeople.Materials and methodsFour digital smile photographs with altered gingival margin position of the right maxillary incisor (0, 1, 2, and 3 mm) were presented to a sample of 232 respondents (71.1% female; 28.9% male): 42 dental specialists, 63 dentists, 33 dental students (1^st to 3^rd year), 38 dental students (4^th to 6^th year) and 56 laypeople. The questionnaire consisted of four randomly displayed photographs, administered via Google Form, and respondents were asked to rate the images on a scale from 1 to 5, from the least attractive to the most attractive. A statistical analysis was performed using the TIBCO Statistica program (v. 13.3. 0, TIBCO Software Inc., Palo Alto, CA, USA; 2017). According to the Shapiro- Wilk''s test, the data were not distributed normally. The Kruskal-Wallis test with post hoc multiple comparisons with the Bonferroni adjustment were used to compare group esthetic scores and to determine the threshold levels of deviation at which each group was discriminated between esthetic and non-esthetic situations.ResultsMedian values of esthetic scores decreased in all groups as the gingival asymmetries increased. Dental professionals were significantly more critical of esthetics than laypeople in all levels of asymmetry. The greatest difference was found for 2 mm of gingival asymmetry (p=0.002).ConclusionFrom the results of our study, we can conclude that the perception of gingival asymmetries in the esthetic zone of smile differs among dental specialists, doctors, students, and laypeople. Dental specialists, doctors, and clinical students were more critical of these asymmetries, while preclinical students and laypeople noticed only 2 mm or more of gingival asymmetry of central incisors.     

带种植体软硬组织磨片手工制作方法的体会

目的探讨手工制作带种植体软硬组织磨片的制作方法及染色技巧。方法 40颗带种植体软硬组织标本采用塑料包埋技术,使用Leica 1600硬组织切片机将包埋好的标本切取带种植体软硬组织厚约200μm,然后手工砂纸打磨成50~70μm,通过亚甲基蓝-酸性品红染色后观察种植体软硬组织的组织学变化。结果 40颗种植体包埋成功,无气泡,组织透明致密;Leica 1600切片机共切片80张,手工磨片及染色失败16张,成功率80.0%;手工制作的带种植体软硬组织磨片能成功的观察骨结合的情况以及种植体软组织袖口的变化。结论采用塑料包埋技术及Leica1600硬组织切片机制作的带种植体软硬组织磨片,通过规范化操作,选择合适的染色方法,能成功广泛的应用于种植体骨整合及软组织整合的研究。     

即刻种植利用愈合基台封闭创口并保持牙龈形态的临床初探

目的 探讨即刻种植中利用愈合基台封闭伤口并保持牙龈自然形态的技术要点,并评估初期临床效果.方法 31例患者在无创拔牙后即刻植入种植体并用Bio-Oss植骨,同时安装愈合基台,3个月后行烤瓷冠修复,修复后平均追踪观察9个月.结果 除1颗种植体于植入后2周脱落外,其余种植体骨结合良好,牙龈原始形态基本完整保存.修复后至修复后3～16个月复查,临床效果满意.结论 在单牙即刻种植中利用愈合基台封闭创口并保持牙龈自然形态的临床方法安全简便,修复美学效果好.     

Stability of the mucosal topography around single-tooth implants and adjacent teeth: 1-year results

This study evaluated the soft tissue stability around 10 single-tooth implants. All cases were treated following the same protocol, which included guided bone regeneration and connective tissue grafting. One year after prosthesis insertion the soft tissue shrinkage on the buccal side of the implant crown was 0.6 mm on average. The soft tissue volume in the papilla area increased on average by 0.375 mm, and none of the papillae lost volume.     

Clinical and radiographic evaluation of soft and hard tissue changes around implants: a pilot study

BACKGROUND: The aim of this study was to evaluate the clinical and radiographic changes in the peri-implant tissues around one-stage implants with different smooth neck portion lengths before and after functional prosthetic loading. METHODS: Twelve one-stage implants were placed in adult patients with bilateral edentulous posterior mandibular ridges. The sites were randomly assigned into two groups of six each: group 1: 2.8 mm neck implants and group 2: neck implants. The parameters plaque index (PI), gingival index (GI), probing depth (PD), gingival margin level (GML), relative clinical attachment level (r-CAL), and optical density (OD) were measured at loading (4 months) and 12 months after implant placement. The radiographic parameter osseous level (OL) was measured at implant placement, loading, and at 12 months. Analysis of variance and the paired Student t test were used to detect difference over time and between groups. RESULTS: The results showed significant differences (P<0.05) for both groups for PD, r-CAL, and OL for intragroup comparisons over time. However, no significant differences were found for PI, GI, PD, GML, OD, and OL for between-group comparisons. CONCLUSION: Bony loss occurred before loading, supporting the soft tissues and maintaining the biologic width irrespective of the smooth portion length.     

Immediate single-tooth implants in the anterior maxilla: a 1-year case cohort study on hard and soft tissue response

Aim: The objective of the present study was to assess implant survival rate, hard and soft tissue response and aesthetic outcome 1 year after immediate placement and provisionalization of single-tooth implants in the pre-maxilla. All patients underwent the same strategy, that is mucoperiosteal flap elevation, immediate implant placement, insertion of a grafting material between the implant and the socket wall and the connection of a screw-retained provisional restoration.
Material and Methods: Thirty consecutive patients were treated for single-tooth replacement in the aesthetic zone by means of immediate implant placement and provisionalization. Reasons for tooth loss included caries, periodontitis or trauma. At 6 months, provisional crowns were replaced by the permanent ones. Clinical and radiographic evaluation was completed at 1, 3, 6 and 12 months to assess implant survival and complications, hard and soft tissue parameters and patient's aesthetic satisfaction.
Results: One implant had failed at 1 month of follow-up, resulting in an implant survival rate of 97%. Radiographic examination yielded 0.98 mm mesial, respectively, 0.78 mm distal bone loss. Midfacial soft tissue recession and mesial/distal papilla shrinkage were 0.53, 0.41and 0.31 mm, respectively. Patient's aesthetic satisfaction was 93%.
Conclusions: The preliminary results suggest that the proposed strategy can be considered to be a valuable treatment option in well-selected patients.     

Comparative finite element analysis of mandibular posterior single zirconia and titanium implants: a 3-dimensional finite element analysis

PURPOSEZirconia has exceptional biocompatibility and good mechanical properties in clinical situations. However, finite element analysis (FEA) studies on the biomechanical stability of two-piece zirconia implant systems are limited. Therefore, the aim of this study was to compare the biomechanical properties of the two-piece zirconia and titanium implants using FEA.MATERIALS AND METHODSTwo groups of finite element (FE) models, the zirconia (Zircon) and titanium (Titan) models, were generated for the exam. Oblique (175 N) and vertical (175 N) loads were applied to the FE model generated for FEA simulation, and the stress levels and distributions were investigated.RESULTSIn oblique loading, von Mises stress values were the highest in the abutment of the Zircon model. The von Mises stress values of the Titan model for the abutment screw and implant fixture were slightly higher than those of the Zircon model. Minimum principal stress in the cortical bone was higher in the Titan model than Zircon model under oblique and vertical loading. Under both vertical and oblique loads, stress concentrations in the implant components and bone occurred in the same area. Because the material itself has high stiffness and elastic modulus, the Zircon model exhibited a higher von Mises stress value in the abutments than the Titan model, but at a level lower than the fracture strength of the material.CONCLUSIONOwing to the good esthetics and stress controllability of the Zircon model, it can be considered for clinical use.     

拔牙窝内植入不同深度骨水平种植体周围软硬组织改建的组织形态变化

目的 比较新鲜拔牙窝内植入不同深度种植体后软、硬组织的变化。方法 6只成年拉布拉多犬的双侧前磨牙拔除后,立即将24颗种植体以不同深度植入拔牙窝内。将Straumann^®骨水平种植体按以下不同深度植入拔牙窝—颊侧牙槽嵴下2 mm,颊侧牙槽嵴下1 mm,与牙槽嵴齐平,以及颊侧牙槽嵴上方1 mm。愈合6个月后采集样本,获得未脱钙切片,进行组织学观察、测量,获得垂直骨吸收和生物学宽度。采用SPSS 19.0软件包对数据进行统计学分析。结果 所有种植体均获得成功骨结合。骨吸收以种植体植入牙槽嵴下2 mm处最显著（P<0.05）。以不同深度植入时,生物学宽度无显著差别。结论 在新鲜拔牙窝内植入种植体时,不同植入深度对骨吸收有影响。当植入深度为骨下2 mm时,骨吸收最多。     

Radiotherapy and the survival of dental implants: a systematic review

For patients with head and neck cancer, the effects of treatment with adjuvant radiotherapy can be devastating. Frequently there is loss of function due to tooth loss, pain and discomfort from xerostomia and mucositis, and a significant psychosocial impact. Dental implants provide an effective means of rehabilitation for many, but irradiation poses a unique set of challenges that can affect the outcome of treatment. The aims of this review were to find out whether radiotherapy in these patients affects the survival of dental implants, and to discuss details of pertinent influencing factors. An electronic search of the Medline, Web of Science, and CENTRAL databases was done to identify studies on the survival of implants in irradiated patients within specified inclusion and exclusion criteria. No restriction was placed on the year of publication. The primary outcome measure was implant survival. Seven studies involving 441 participants and 1502 implants placed into irradiated bone were included. Meta-analysis indicated that survival was significantly higher in the mandible compared with the maxilla (p = 0.04), and in non-irradiated cases compared with irradiated cases (p < 0.001). Other factors that showed a strong association with survival were radiation dose and timing of surgery. Implant-based rehabilitation is a viable option for head and neck cancer patients who have undergone radiotherapy. Whilst the short to medium-term implant survival in these cases is high, multiple factors require careful consideration for a favourable outcome. Further high-quality research and randomised controlled trials are required in this field.     

Astra Tech single-tooth implants: an audit of patient satisfaction and soft tissue form

AIM: To investigate patient centred outcomes, soft tissue morphology, and bone levels. MATERIAL AND METHODS: Sixty-six subjects, who had completed treatment for a single implant restoration at least l year previously. Appearance was recorded photographically and bone levels and interdental contact points measured from intra-oral radiographs using a x 7 scale loupe. Subjects completed a satisfaction questionnaire. RESULTS: Subjects were highly satisfied with all aspects of the restoration including the appearance of the soft tissue (median shape/colour score 6 on scale 1-6). Twenty-eight sites in 20 subjects had no contact point between implant crown and adjacent tooth. A normal height papilla was judged to be present in 19 of these sites. These were excluded from the subsequent analysis. In the remaining 46 subjects with contact points the presence (JEMT score 3) or deficiency (score 1/2) of the papilla was significantly related to the distance to the bone level on the adjacent tooth and implant head. Differences were observed between the mesial and distal aspects of the implant restoration. CONCLUSIONS: Examining clinicians were more critical of the restorations than the patients. The presence of a complete papilla was associated with a slightly greater distance from contact point to bone level than previously reported.     

即刻种植后种植体周围软硬组织变化的临床观察

目的 观察即刻种植修复缺失牙后软硬组织的临床变化情况.方法 10例患者的种植体20枚(直径为4.1或4.8 mm,长度10或12 mm),其中10枚为即刻种植,10枚为常规种植,在即刻植入的同时进行引导骨再生(guided bone regeneration,GBR)的骨增量手术.完成义齿修复后随访观察1年,通过X线片分别测量即刻种植和常规种植的硬组织变化量,进行对比分析.同时记录各组种植体的牙周探诊深度和龈乳头指数,分析即刻种植对牙周软组织有无影响.结果 1年后10例患者的种植体20枚均存留,患者主观全部满意.种植体周软硬组织无病理性异常.1年后硬组织平均吸收值常规种植组(1.76±0.21) mm,即刻种植组(1.80±0.15) mm,两者比较差异无统计学意义(P＞0.05).对比1年后两组牙周探诊深度:即刻种植组(2.31 ±0.84)mm,常规种植组(2.27±0.84) mm,两组间差异无统计学意义(P＞0.05).两组龈乳头指数的频数分布比较,差异无统计学意义(P＞0.05).结论 即刻种植的近期种植体周软硬组织变化达到临床治疗要求.     

Evaluation of soft tissue around single-tooth implant crowns: the pink esthetic score

AIM: In this study, the reproducibility of a newly developed pink esthetic score (PES) for evaluating soft tissue around single-tooth implant crowns was assessed. The effect of observer specialization was another point of interest. MATERIAL AND METHODS: Twenty observers (five prosthodontists, five oral surgeons, five orthodontists and five dental students) were given photographs of 30 single-tooth implant crowns. Seven variables were evaluated vs. a natural reference tooth: mesial papilla, distal papilla, soft-tissue level, soft-tissue contour, alveolar process deficiency, soft-tissue color and texture. Using a 0-1-2 scoring system, 0 being the lowest, 2 being the highest value, the maximum achievable PES was 14. Each observer was requested to make two assessments at an interval of 4 weeks. At the second assessment, the photographs were scored in the reverse order. RESULTS: The mean PES of evaluations at the first assessment (n=600) was 9.46 (+/-3.81 SD), and 9.24 (+/-3.8 SD) at the second one. The difference between these two means was not significant statistically (P=0.6379). Implant-related mean PES for single-tooth implants varied from 2.28 to 13.8, with standard deviations between 0.46 and 3.51. Very poor and very esthetic restorations showed the smallest standard deviations. The mean total PES was 10.6 for the prosthodontists, 9.2 for the oral surgeons, 9.9 for the dental students and 7.6 for the orthodontists. CONCLUSIONS: The PES reproducibly evaluates peri-implant soft tissue around single-tooth implants. Thus, an objective outcome of different surgical or prosthodontic protocols can be assessed. Orthodontists were clearly more critical than the other observers.     

下颌前突患者术后软组织侧貌美学缺陷分析

目的研究下颌前突畸形患者术后软组织侧貌与中国美貌人群的差异,分析其存在的美学缺陷,为进一步提高治疗效果提供参考。 方法选取经正畸-正颌联合治疗术后6个月以上的下颌前突畸形患者52例（男31例、女21例）,拍摄头颅定位侧位片进行软组织侧貌测量,并与王兴所测中国美貌人群之测量结果进行比较分析,男女两组分别与美貌人群组数据进行独立样本t检验。 结果与美貌人群相比,男女两组下颌前突畸形患者术后软组织侧貌测量项目均有多点差异,主要表现为：（1）男性患者Ns、Prn、Cm及Sn X坐标值均较小（P<0.05）,女性仅Ns点X坐标值较小（P<0.05）,提示鼻根部较扁平;（2）两组颏唇沟角增大（P<0.05）,Si点、UL点至"审美平面"距离减小（P<0.05）,LL点基本位于"审美平面"右侧,为负值（P<0.05）,提示术后颏唇沟变浅,下唇较突,颏部轮廓欠佳;（3）两组患者面中份与面下份软组织线距比减小（P<0.05）,提示面中份与面下份比例不协调,面下三分之一长度相对较长;（4）两组患者C-Gn′软组织线距减小（P<0.05）,同时C-Gn′/Sn-Gn′线距比减小（P<0.05）,提示侧面观下颌缘长度减小。 结论患者上下颌发育不协调、手术方案的选择及正畸治疗等均影响其术后的侧貌美观。下颌前突畸形患者单行下颌后退手术其软组织侧貌存在不同程度美学缺陷,有必要行进一步综合治疗以提高美学效果。     

Correlation between microhardness and wear resistance of dental alloys against monolithic zirconia

PURPOSEThe aim of this study is to compare the hardness according to the conditions of metal alloys. Moreover, the correlation between the cast crown hardness before and after wear testing and the degree of wear for each dental alloy was assessed.MATERIALS AND METHODSCast crowns of three metal alloys (Co-Cr, gold, and Ni-Cr alloys) opposing smooth-surface monolithic zirconia were used. The Vickers microhardness of the ingot (which did not undergo wear testing) and the cast crown before and after wear testing were measured for each alloy. Two-way ANOVA and Scheffé tests were used to compare the measured hardness values. Moreover, the Pearson correlation coefficient was used to evaluate the relationship between the surface hardness and the wear of the cast crown (α=.05).RESULTSThere was no significant difference in the hardness before and after wear testing for the gold alloy (P>.05); however, the hardness of the worn surface of the cast crown increased compared to that of the cast crown before the wear tests of Ni-Cr and Co-Cr alloys (P<.05). Furthermore, there was no correlation between the wear and hardness of the cast crown before and after wear testing for all three metal alloys (P>.05).CONCLUSIONThere was a significant difference in hardness between dental alloys under the same conditions. No correlation existed between the surface hardness of the cast crown before and after wear testing and the wear of the cast crown.