Effect of different thread configurations on hydrophilic implant stability. A split-mouth RCT

Abstract This split-mouth randomized controlled trial aimed to evaluate the primary and secondary stability of hybrid implants with different thread configurations and hydrophilic surfaces. Twenty patients with a partially edentulous maxilla were selected. These patients received two types of implants with the same hydrophilic surface: CTP group: Cylindrical-Tapered implant with perforating threads; CTH: Cylindrical-Tapered implant with hybrid threads configuration (perforating and condensing threads). The primary and secondary stability parameters were measured by insertion torque and resonance frequency analysis at the time of implant placement and 7, 28, 56, and 90 days after the surgical procedure. The paired t-test was used to compare the data on the implant's stability between the groups. The statistical analysis was performed with a confidence level set at 95%. It was found that the implants in the CTH group presented higher primary stability values ​​at the time of implant placement, due to the higher ISQ (63.61 ± 9.44 vs. 40.59 ±7.46) and insertion torque (36.92 ± 16.50 Ncm vs. 28.00 ± 14.40 Ncm), than the implants in the CTP group. The CTH group presented higher ISQ values ​​in all follow-up periods: 7 days (68.67 ± 7.60 vs. 41.55 ± 9.07), 28 days (68.61 ± 5.98 vs. 47.90 ±13.10), 56 days (74.09 ± 3.96 vs. 55.85 ± 13.18), and 90 days (75.45 ± 4.02 vs. 63.47 ± 6.92) after implant placement. Hybrid implants with perforating and condensing threads demonstrated greater stability than hybrid implants with only perforating threads.

Resumo O objetivo deste estudo controlado randomizado de boca dividida foi avaliar a estabilidade primária e secundária de implantes híbridos com diferentes configurações de rosca e superfícies hidrofílicas. Vinte pacientes com maxila parcialmente edêntula foram selecionados. Esses pacientes receberam dois tipos de implantes com a mesma superfície hidrofílica: Grupo CTP: Implante cilíndrico-cônico com roscas perfurantes; Grupo CTH: Implante cilíndrico-cônico com roscas perfurantes e condensadoras. Os parâmetros de estabilidade primária e secundária foram medidos por análise de torque de inserção e frequência de ressonância no momento da colocação do implante e 7, 28, 56 e 90 dias após o procedimento cirúrgico. O teste t-pareado foi utilizado para comparação dos dados de estabilidade entre os grupos. A análise estatística foi executada levando-se em consideração um nível de confiança de 95%. Constatou-se que os implantes do grupo CTH apresentaram maiores valores de estabilidade primária no momento da colocação do implante, devido ao maior ISQ (63.61 ± 9.44 vs. 40.59 ±7.46) e torque de inserção (36.92 ± 16.50 Ncm vs. 28.00 ± 14.40 Ncm), do que os implantes do grupo CTP. Implantes do grupo CTH apresentaram valores de ISQ superiores em todos os períodos de acompanhamento: 7 dias (68.67 ± 7.60 vs. 41.55 ± 9.07), 28 dias (68.61 ± 5.98 vs. 47.90 ±13.10), 56 dias (74.09 ± 3.96 vs. 55.85 ± 13.18) e 90 dias (75.45 ± 4.02 vs. 63.47 ± 6.92). Os implantes híbridos com roscas perfurantes e condensantes demonstraram maior estabilidade do que os implantes híbridos com apenas roscas perfurantes.

Radiologic Comparison of Humeral Position according to the Implant Designs Following Reverse Shoulder Arthroplasty: Analysis between Medial Glenoid/Medial Humerus, Lateral Glenoid/Medial Humerus, and Medial Glenoid/Lateral Humerus Designs

BACKGROUND: The currently available reverse shoulder arthroplasty (RSA) designs can be classified into medial glenoid/medial humerus (MGMH), lateral glenoid/medial humerus (LGMH), and medial glenoid/lateral humerus (MGLH) prosthesis designs. The purpose of this study was to radiologically analyze the effect of different RSA designs on humeral position following RSA. METHODS: A total of 50 patients who underwent primary RSA were retrospectively analyzed. Among 50 patients, 33 patients (group A: MGMH) underwent RSA with Aequalis system (Wright, Inc, Bloomington, MN, USA), 6 (group B: LGMH) with Aequalis system using bony increased offset, and 11 (group C: MGLH) with Aequalis Ascend Flex system. The acromiohumeral distance, acromioepiphyseal distance (AED), lateral humeral offset (LHO), LHO from the center of rotation (LHO(COR)), and deltoid length were radiologically measured to quantify the distalization and lateralization of the humerus. RESULTS: The increment in postoperative AED was 19.92 ± 3.93 mm in group A, 24.52 ± 5.25 mm in group B, and 25.97 ± 5.29 mm in group C, respectively (p=0.001). The increment in postoperative LHO was 0.13 ± 6.30 mm, 8.00 ± 12.14 mm, and 7.42 ± 6.88 mm, respectively (p=0.005). The increment in postoperative LHOCOR was 20.76 ± 6.06 mm, 22.04 ± 5.15 mm, and 28.11 ± 4.14 mm, respectively (p=0.002). CONCLUSIONS: The radiologic analysis of the effect of different RSA designs on humeral position following RSA showed significant differences in the increment in postoperative AED, LHO, and LHO(COR) between the 3 groups. Therefore, MGLH design seems to be more effective for humeral distalization and lateralization compared to original Grammont design.

Implant Design in Cementless Hip Arthroplasty / 대한고관절학회지

When performing cementless hip arthroplasty, it is critical to achieve firm primary mechanical stability followed by biological fixation. In order to achieve this, it is essential to fully understand characteristics of implant design. In this review, the authors review fixation principles for a variety of implants used for cementless hip replacement and considerations for making an optimal selection.

Implante Cone Morse em área anterior: relato de caso clínico / Morse taper implant: a case report

Introdução: o aprimoramento das técnicas de reabilitação bucal permite melhor qualidade e previsibilidade nos resultados finais dos tratamentos que demandam alta performance estética. Métodos: esse artigo descreve um caso clínico de fratura radicular no dente 11, onde realizou-se planejamento reverso e optou-se pela seguinte sequência de tratamento: exodontia, instalação de implante imediato associado a regeneração óssea guiada e instalação de coroa temporária imediata. Preocupando-se em minimizar a reabsorção óssea peri-implantar, manter saúde do tecido periodontal e obter alta performance estética, optou-se pelo implante com conexão do tipo Morse, por sua maior estabilidade biomecânica e selamento bacteriano. O dente provisório foi anteriormente confeccionado seguindo a simetria dos dentes adjacentes, dos lábios e do tecido gengival, a fim de se criar uma harmonia global no sorriso do paciente. Conclusão: concluiu-se que, na Implantodontia atual, não basta apenas obter o adequado posicionamento tridimensional do implante, mas, sim, aliar um planejamento adequado a uma conexão eficiente, posicionando o implante de acordo com biótipo periodontal do paciente, de forma a prever um perfil de emergência satisfatório à futura prótese, devolvendo estética, função e fonética ao paciente...

Introduction: Improvements in oral rehabilitation techniques allow esthetically demanding treatments to yield better and more predictable results. Methods: This paper reports a case of root fracture of tooth #11 treated by means of reverse planning comprising the following steps: tooth extraction, immediate implant placement associated with guided bone regeneration and immediate temporary crown placement. Due to its biomechanical stability and bacterial sealing properties, a Morse taper connection implant was used to reduce peri-implant bone resorption, preserve periodontal tissue health and yield highly satisfactory esthetic results. The temporary tooth had been previously fabricated in accordance with the symmetry of adjacent teeth, lips and gingival tissue, which resulted in a pleasant smile. Conclusion: It is reasonable to conclude that establishing an appropriate three-dimensional positioning of implants is not enough for Implantodontics. It requires that an appropriate planning be associated with an efficient connection so as to place an implant in accordance with patient's periodontal biotype, thus predicting a satisfactory emergence profile, in addition to recovering patient's esthetics, function and speech...

The effect of implant design on the stress distribution in a three-unit implant-supported distal cantilever fixed partial denture: A three-dimensional finite-element analysis.

Context: Implant design influences the stress distribution in an implant-supported distal cantilever fixed partial denture and supporting bone tissue. Aim: The purpose of this study was to investigate the effect of implant design on the stress distribution in the framework, implant, and surrounding bone, using a three-dimensional finite-element analysis. Materials and Methods: A three-dimensional finite-element model of a mandibular section of bone with implants placed in the first and second premolar region was created to support a distal cantilever fixed partial denture. A one-piece and two-piece implant and its suprastructure were simulated into wire frame models using Pro engineer (Pro E) program. Four models were created in this study. Results: Comparative analysis of all models showed that the maximum stress overall was in the cervical portion of the secondary abutment. When used in combination, the maximum stress was when the two-piece implant was used as secondary abutment. The one-piece implant showed less stress compared to its counterpart when used as secondary abutment. The maximum stress distribution in the bone was around the neck region of the secondary implant. Conclusion: Within the limitations of this study, it can be concluded that stress distribution is better in a one-piece implant design when compared with the two-piece implant design, with stress concentration being more at the junction of the abutment and the implant fixture in the two-piece implant. When implants are used as abutments (either primary or secondary), irrespective of their position and design, the secondary implant shows the maximum amount of stresses.

The effects of different pilot-drilling methods on the mechanical stability of a mini-implant system at placement and removal: a preliminary study / 대한치과교정학회지

OBJECTIVE: To investigate the effects of different pilot-drilling methods on the biomechanical stability of self-tapping mini-implant systems at the time of placement in and removal from artificial bone blocks. METHODS: Two types of artificial bone blocks (2-mm and 4-mm, 102-pounds per cubic foot [102-PCF] polyurethane foam layered over 100-mm, 40-PCF polyurethane foam) were custom-fabricated. Eight mini-implants were placed using the conventional motor-driven pilot-drilling method and another 8 mini-implants were placed using a novel manual pilot-drilling method (using a manual drill) within each of the 2-mm and 4-mm layered blocks. The maximum torque values at insertion and removal of the mini-implants were measured, and the total energy was calculated. The data were statistically analyzed using linear regression analysis. RESULTS: The maximum insertion torque was similar regardless of block thickness or pilot-drilling method. Regardless of the pilot-drilling method, the maximum removal torque for the 4-mm block was statistically higher than that for the 2-mm block. For a given block, the total energy at both insertion and removal of the mini-implant for the manual pilot-drilling method were statistically higher than those for the motor-driven pilot-drilling method. Further, the total energies at removal for the 2-mm block was higher than that for the 4-mm block, but the energies at insertion were not influenced by the type of bone blocks. CONCLUSIONS: During the insertion and removal of mini-implants in artificial bone blocks, the effect of the manual pilot-drilling method on energy usage was similar to that of the conventional, motor-driven pilot-drilling method.

A comparative study on the initial stability of different implants placed above the bone level using resonance frequency analysis

PURPOSE: This study evaluated the initial stability of different implants placed above the bone level in different types of bone. MATERIALS AND METHODS: As described by Lekholm and Zarb, cortical layers of bovine bone specimens were trimmed to a thickness of 2 mm, 1 mm or totally removed to reproduce bone types II, III, and IV respectively. Three Implant system (Branemark System(R) Mk III TiUnite(TM), Straumann Standard Implant SLA(R), and Astra Tech Microthread(TM)-OsseoSpeed(TM)) were tested. Control group implants were placed in level with the bone, while test group implants were placed 1, 2, 3, and 4 mm above the bone level. Initial stability was evaluated by resonance frequency analysis. Data was statistically analyzed by one-way analysis of variance in confidence level of 95%. The effective implant length and the Implant Stability Quotient (ISQ) were compared using simple linear regression analysis. RESULTS: In the control group, there was a significant difference in the ISQ values of the 3 implants in bone types III and IV (P<.05). The ISQ values of each implant decreased with increased effective implant length in all types of bone. In type II bone, the decrease in ISQ value per 1-mm increase in effective implant length of the Branemark and Astra implants was less than that of the Straumann implant. In bone types III and IV, this value in the Astra implant was less than that in the other 2 implants. CONCLUSION: The initial stability was much affected by the implant design in bone types III, IV and the implant design such as the short pitch interval was beneficial to the initial stability of implants placed above the bone level.

Effect of bone-implant contact pattern on bone strain distribution: finite element method study / 대한치과보철학회지

PURPOSE: To date most of finite element analysis assumed the presence of 100% contact between bone and implant, which is inconsistent with clinical reality. In human retrieval study bone-implant contact (BIC) ratio ranged from 20 to 80%. The objective of this study was to explore the influence of bone-implant contact pattern on bone of the interface using nonlinear 3-dimensional finite element analysis. MATERIALS AND METHODS: A computer tomography-based finite element models with two types of implant (Mark III Branemark(R), Inplant(R)) which placed in the maxillary 2nd premolar area were constructed. Two different degrees of bone-implant contact ratio (40, 70%) each implant design were simulated. 5 finite element models were constructed each bone-implant contact ratio and implant design, and sum of models was 40. The position of bone-implant contact was determined according to random shuffle method. Elements of bone-implant contact in group W (wholly randomized osseointegration) was randomly selected in terms of total implant length including cortical and cancellous bone, while ones in group S (segmentally randomized osseointegration) was randomly selected each 0.75 mm vertically and horizontally. RESULTS: Maximum von Mises strain between group W and group S was not significantly different regardless of bone-implant contact ratio and implant design (P=.939). Peak von Mises strain of 40% BIC was significantly lower than one of 70% BIC (P=.007). There was no significant difference between Mark III Branemark(R) and Inplant(R) in 40% BIC, while average of peak von Mises strain for Inplant(R) was significantly lower (4886 +/- 1034 microm/m) compared with MK III Branemark(R) (7134 +/- 1232 microm/m) in BIC 70% (P<.0001). CONCLUSION: Assuming bone-implant contact in finite element method, whether the contact elements in bone were wholly randomly or segmentally randomly selected using random shuffle method, both methods could be effective to be no significant difference regardless of sample size.

Influência da técnica cirúrgica e da forma do implante na estabilidade primária / Influence of surgical technique and implant design on the primary stability

A estabilidade primária dos implantes dentários influencia no índice de sucesso e na escolha do protocolo de tratamento. Para o emprego da técnica da carga imediata é essencial que o implante apresente boa estabilidade primária. No presente trabalho implantes com a forma cilíndrica e com perfil cônico foram inseridos em resina poliuretana e em blocos de costela suína. Determinaram-se os torques de inserção e de remoção Os resultados mostraram que a inserção dos implantes cilíndricos exige maior torque e que quanto menor o diâmetro da última fresa empregada para preparar o sítio de instalação, maior o torque para inserir os implantes.

The primary stability of dental implants influences the success rate and treatment protocol. To achieve success in the dental implant immediate loading is essential that the implant presents higher primary stability. In the present study dental implants with cylindrical and conical design were inserted into polyurethane and pork rib blocks. The results showed that the insertion of the cylindrical implant requires higher insertion torque than conical implant. The placement of dental implants using an undersized preparation technique resulted in enhanced primary implant stability.

Study on radiographic evaluation of marginal bone loss around osseointegrated implant after functional loading

PURPOSE: The purpose of this study was to evaluate marginal bone loss to the bone crest functionally loaded for up to eighteen months and also with regard to other variables of interest. MATERIAL AND METHODS: 135 endosseous implants(GS II, Osstem, South Korea) were placed in 35 patients. The design of GS II implant is straight with the microthread. Radiographic examinations were conducted at baseline (implant loading) and 3, 6, 9, 12 and 18 months after loading. Marginal bone level measurement was made from the reference point to the lowest observed point of contact of the marginal bone with the fixture. The reference point of the fixture was the border between the blasted surface and machined surface of the fixture. RESULTS: Implants were on function for a mean 12.7 months(range, 3-18 months). For the 56 maxillary and 79 mandibular implants, mean marginal bone loss was 0.68 mm and 0.70 mm. Implants placed maxillary posterior area displayed more crestal bone loss than the other position. The difference between mesial and distal bone levels was statistically significant (p0.05). CONCLUSION: This study indicates the amount of marginal bone loss around implant has maintained a relative stable during follow-up periods.

Marginal tissue response to different Implant neck design / 대한치과보철학회지

STATEMENT OF PROBLEM: Loss of the marginal bone to the first thread have been accepted but continuous effort have been made to reduce this bone loss by varying implant design and surface texture. PURPOSE: This animal study has examined the histomorphometric variations between implants with micro-thread, micro-grooved and turned surfaced neck designs. MATERIAL AND METHODS: Four mongrel dogs have been used the premolars removed and left to heal for three months. One of each implant systems with turned neck, micro-thread and micro-grooved were placed according to the manufacturers' protocol and left submerged for 8 and 12 weeks. These were then harvested for histological examination. RESULTS: The histologically all samples were successfully ossointegrated and active bone remodelling adjacent to implants. With the micro-grooved implants 0.40 mm and 0.26 mm of the marginal bone level changes were observed at 8 and 12 weeks respectively. The micro-threaded implants had changes of 0.79 mm and 0.56 mm at 8 and 12 weeks respectably. The turned neck designed implants had marginal bone level changes of 1.61 mm and 1.63 mm in 8 and 12 weeks specimens. A complex soft tissue arrangement could be observed against micro-threaded and micro-grooved implant surfaces. CONCLUSION: Within the limitations of this study, it could be concluded that implants with micro-grooved had the least and the turned neck designed implants had the most changes in the marginal bone level. The textured implant surfaces affect soft tissue responses.

Effect of implant designs on insertion torque and implant stability quotient (ISQ) value / 대한치과보철학회지

Statement of problem. Primary implant stability has long been identified as a prerequisite to achieve osseointegration. So the application of a simple, clinically applicable noninvasive test to assess implant stability and osseiointegratation are considered highly desirable. Purpose. The purpose of this study was to evaluate the ISQ value and the insertion torque of the 3 different implant system, then to evaluate whether there was a correlation between ISQ value and insertion torque; and to determine whether implant design has an influence on either insertion torque or ISQ value. Material and method. The experiment was composed of 3 groups: depending on the implant fixture design. Group1 was Bra.nemark type parallel implant in 3.75*7mm. Group2 was Oneplant type straight implant in 4.3*8.5mm. Group3 was Oneplant type tapered implant in 4.3*8.5mm. Depending on the density of the bone, 2 types of bone were used in this experiment. Type I bone represented for cortical bone, type II bone represented for cancellous bone. With the insertion of the implant in type I and type II bone, the insertion torque was measured, then the ISQ value was evaluated, and then the correlation between insertion torque and ISQ value was analyzed Result and conclusion. Within the limitations of this study, the following conclusions were drawn. 1. Within the 3 different implants, the insertion torque value and ISQ value were higher in type I bone, when compared with type II bone.(p0.05) 4. Significant linear correlation was found in Bra.nemark type parallel implant: 3.75*7mm in type II bone.

Osteolysis in Cementless Total Knee Arthroplasty

Eighty-four cementless primary total knee arthroplasties were performed from June 1989 to May 1993, and the prevalence and characteristics of osteolysis were determined after a mean follow-up of 6.4 years(range, 5 to 8.1 years). Eighteen knees(21.4%) were identified as being associated with osteolysis, and the incidence of osteolysis was 10,7% for the femur and 13.1% for the tibia. Osteolysis was first noted radiographically at an average postoperative 4.7 years(range, 2.5 to 8, i years). Osteolysis of the femur was identified adjacent to the nonporous-coated regions of the anterior and posterior flanges of the components, The medial screw was more frequently associated with osteolytic lesion than the lateral one. Ten(55.6%) of the 18 prostheses were revised, 5 for advanced polyethylene wear, 3 for failed tibia1 fixation, and 2 for severe osteolysis. Significant factors associated with osteolysis were increased body weight(p<0.05) and malalignment(p<0.05). Femoral osteolysis was more common in Ortholoc design(20.0%) than in AMK design(4.1%). The AMK prosthesis(16.3%) showed higher in an incidence of screw osteolysis and tibial osteolysis than Ortholoc prosthesis(8.6%). The nonporous-coated flanges of the components and the polyethylene locking mechanism may be responsible for the differences in the incidence and region of osteolysis.