Mini Implants Research Articles

Ligature Guide for Implant Placement

ABSTRACT Aim Planning an anchorage requirements of a case for effecient biomechanics is one of the important step in success of treatment outcomes. There are many means to reinforce anchorage. Since last decade, use of mini implants for absolute anchorage has gained popularity which does not depend on pateint compliance. Precise positioning of mini-implant is a key for success of absolute anchorage system. We have devised a simple guide made up of ligature wire, which is a useful tool for an accurate implant placement. The proposed implant guide is a useful aid for accurate placement of implant, which minimizes chances of root damage. Background Precise positioning of mini-implant is of paramount importance for success of absolute anchorage system. How to cite this article Durgekar SG. Ligature Guide for Implant Placement. Int J Experiment Dent Sci 2017;6(1):51-53.

Treatment of a Class II Division 2 Malocclusion in a Teenage Patient: Clinical Case Report

This article describes the orthodontic treatment of an adolescent patient presenting a class II skeletal, convex profile, mesofacial biotype, upper dental midline deviated 1 mm to the left, Class I bilateral molar, canine distoclusion of ½ right unit and left canine relationship non-determinable because piece 23 is in ectopic position, proinclination and inferior protrusion. The treatment plan was to distalize the maxillary molars and create enough space to incorporate pieces 13, 23 in the dental arch, a pendulum appliance supported with two orthodontic mini implants were used. The active treatment lasted 18 months and at the end of it, all the objectives were fulfilled, resulting in facial balance. The pendulum appliance is a good alternative for a Class II dental correction, it produces distalization of the maxillary molars in an optimal treatment time.

Evaluation of the PROPEL® mini sinus implant for the treatment of frontal sinus disease

ABSTRACTIntroduction: Propel and Propel Mini sinus implants are mometasone furoate-coated bioabsorbable stents used as an adjunct in the management of chronic rhinosinusitis after endoscopic sinus surgery. The original sinus implant was deployed in the ethmoid sinuses to provide medialization of the middle turbinate, decrease scarring and mucosal adhesions, limit polyp regrowth, and reduce mucosal inflammation. A structurally smaller version of the Propel, the Propel Mini, was developed and now has been approved for endoscopic placement in the frontal sinuses.Areas covered: This evaluation will focus on the technical details of the Propel mini, previous studies documenting Propel’s success in the ethmoid sinuses, and the safety and efficacy of the Propel mini implants in frontal sinus surgery.Expert opinion: Devices such as the Propel and Propel Mini stents are the beginning of a trend towards medication-coated bioabsorbable implants that can be used for sinonasal disease to minimize complications or possible side effects of surgical treatment by an increase of topical drug delivery locally.

Erratum to: Barriers and facilitators to the implementation of orthodontic mini implants in clinical practice: a systematic review.

Erratum to: Barriers and facilitators to the implementation of orthodontic mini implants in clinical practice: a systematic review.

Коэффициенты продольной стабильности дентальных имплантатов

Вводится понятие продольной стабильности дентальных имплантатов. Известно, что прибор Osstell ISQ ( Implant Stability Quotient, Швеция) наряду с вынужденными колебаниями дентальных имплантатов, возникающими под действием поперечных нагрузок, может возбуждать продольные колебания и регистрировать их резонансную частоту. Цель работы обоснование возможности использования коэффициентов продольной стабильности для оценки готовности дентальных имплантатов к функциональным нагрузкам, а также верификация методики их измерения с помощью прибора Osstell ISQ путем сравнения с соответствующими коэффициентами продольной жесткости, измеряемыми методом лазерного тестирования. По сравнению с традиционной предлагаемая методика обладает рядом преимуществ и позволяет создать новую, более совершенную базу для неинвазивного мониторинга процесса остеоинтеграции дентальных имплантатов. Например, использование модифицированных «магнитных заглушек» вместо магнитных штифтов ( SmartPeg ) позволяет проводить измерения коэффициентов продольной стабильности через слизистую оболочку альвеолярной кости, т.е. не раскрывая дентальный имплантат для дальнейшего использования как опору под несъемный зубной протез, а модифицированные «магнитные колпачки» дают возможность определять коэффициенты продольной стабильности мини-имплантатов со сферической головкой, используемых для дополнительной фиксации съемных зубных протезов при полном отсутствии зубов. Необходимо подчеркнуть, что традиционная методика Osstell ISQ не позволяет проводить измерения коэффициентов стабильности указанных мини-имплантатов. Введение коэффициентов продольной стабильности позволило построить простую теоретическую модель колебаний дентальных имплантатов, закрепленных в упругой и вязкоупругой среде, установить связь между коэффициентами продольной стабильности и продольной жесткости, дать оценку несущей способности дентальных имплантатов. Более того, при оценке их готовности к функциональным нагрузкам с помощью коэффициентов продольной стабильности рекомендации остаются прежними, так как отношение коэффициентов стабильности при продольных и поперечных нагрузках должно быть близко к единице.A concept of longitudinal stability is introduced for dental implants. It is well known that the Osstell ISQ device (Implant Stability Quotient, Sweden), along with forced oscillations of dental implants arising under lateral loads, may also excite longitudinal oscillations and register their resonance frequency. The objective of the study is to substantiate possibility to apply quotients of longitudinal stability in order to assess readiness of dental implants for functional loads, as well as to verify methods of their measurement using the Osstell ISQ device by comparison with appropriate quotients of longitudinal rigidity measured by laser testing. In comparison with the traditional technique, the proposed one has a number of advantages and enables creation of a new and more perfect base for noninvasive monitoring of dental implant osteointegration process. For example, the use of modified “magnetic plugs” instead of pins (SmartPeg) allows quotients of longitudinal stability to be measured through a mucous membrane of alveolar bone, i.e. a dental implant will not be open for further use as a fixed denture support, and modified magnetic caps allow determination of quotients of longitudinal stability for spherical headed mini implants used for additional fixation of detachable dentures when teeth are absent totally. Please note that the traditional Osstell ISQ technique does not enable measurements of coefficients of stability for the said mini implants. Introduction of quotients of longitudinal stability has made it possible to create a simple theoretical model of oscillations for dental implants fixed in elastic and viscous-elastic medium, to relate quotients of longitudinal stability and longitudinal rigidity to each other, and to assess bearing capacity of dental implants. Moreover, recommendations remain the same when assessing implant readiness for functional loads using quotients of longitudinal stability since the ratio of quotients of stability for longitudinal and lateral loads approximates unity.

Barriers and facilitators to the implementation of orthodontic mini implants in clinical practice: a systematic review

BackgroundNumerous surveys have shown that orthodontic mini implants (OMIs) are underused in clinical practice. To investigate this implementation issue, we conducted a systematic review to (1) identify barriers and facilitators to the implementation of OMIs for all potential stakeholders and (2) quantify these implementation constructs, i.e., record their prevalence. We also recorded the prevalence of clinicians in the eligible studies that do not use OMIs.MethodsMethods were based on our published protocol. Broad-spectrum eligibility criteria were defined. A barrier was defined as any variable that impedes or obstructs the use of OMIs and a facilitator as any variable that eases and promotes their use. Over 30 databases including gray literature were searched until 15 January 2016. The Joanna Briggs Institute tool for studies reporting prevalence and incidence data was used to critically appraise the included studies. Outcomes were qualitatively synthesized, and meta-analyses were only conducted when pre-set criteria were fulfilled. Three reviewers conducted all research procedures independently. We also contacted authors of eligible studies to obtain additional information.ResultsThree surveys fulfilled the eligibility criteria. Seventeen implementation constructs were identified in these studies and were extracted from a total of 165 patients and 1391 clinicians. Eight of the 17 constructs were scored by more than 50 % of the pertinent stakeholders. Three of these constructs overlapped between studies. Contacting of authors clarified various uncertainties but was not always successful. Limitations of the eligible studies included (1) the small number of studies; (2) not defining the research questions, i.e., the primary outcomes; (3) the research design (surveys) of the studies and the exclusive use of closed-ended questions; (4) not consulting standards for identifying implementation constructs; (5) the lack of pilot testing; (6) high heterogeneity; (7) the risk of reporting bias; and (8) additional shortcomings. Meta-analyses were not possible because of these limitations. Two eligible studies found that respectively 56.3 % (952/1691) and 40.16 % (439/1093) of clinicians do not use OMIs.ConclusionsNotwithstanding the limitations of the eligible studies, their findings were important because (1) 17 implementation constructs were identified of which 8 were scored by more than 50 % of the stakeholders; (2) the various shortcomings showed how to improve on future implementation studies; and (3) the underuse of OMIs in the selected studies and in the literature demonstrated the need to identify, quantify, and address implementation constructs. Prioritizing of future research questions on OMIs with all pertinent stakeholders is an important first step and could redirect research studies on OMIs towards implementation issues. Patients, clinicians, researchers, policymakers, insurance companies, implant companies, and research sponsors will all be beneficiaries.Electronic supplementary materialThe online version of this article (doi:10.1186/s13643-016-0336-z) contains supplementary material, which is available to authorized users.

Changes in biting forces with implant-supported overdenture in the lower jaw: A comparison between conventional and mini implants in a pilot study

The biting ability of patients improves noticeably after receiving implant-supported overdentures in comparison to conventional complete dentures. However, the change of biting with such treatment concepts has been quantitatively investigated in only a limited number of studies. The aim of the present study has been to measure the biting forces of edentulous patients with complete dentures and after receiving implant-supported overdentures.A total of 26 edentulous patients were included. Ten patients received two to four conventional implants (control group, Ø3.3–3.7mm, L11–13mm) and 16 patients received four to five mini implants (study group, Ø1.8–2.4mm, L13–15mm) inserted in the mandibular interforaminal region. All patients received a lower overdenture with ball/rubber ring attachments and a complete denture for the maxilla. The biting forces were measured using Prescale pressure sheets type low before the insertion of implants and after receiving implant-supported overdenture. The measured sheets were later scanned and analysed using FPD-8010E software.The range of biting forces before the insertion of implants was 80N–122N for the control group and 66–88N for the study group. After the insertion of implants, the range of biting forces increased to 167N–235N for the control group and to 81N–138N for the study group. However, the increase in biting forces after the insertion of implants was not significant for either group. No significant difference was obtained between the two implant systems.The biting forces improved after insertion of implants regardless of which implant system was used. However, the degree of improvement is noticeably related to the original bone quality of the mandible at the insertion regions of implants.

The Case for Smaller Diameter Implants.

Dear Editor,Previous work in the dental literature has discussed occlusal over load of dental implants in function.1 Thus larger diameter implants have been advocated.1 However, there are other considerations that may come into play that effect the longevity of an implant. The major parameters are displacement of the implant, occlusal overload, and percutaneous circumference.It may be that the actual larger displacement of large diameter implants impedes bone remodeling, especially at the crest where the bone may be thinner at the facial and lingual as compared with the deep medullary bone.2,4 Even if the crestal bone is greater than 1.8 mm the larger implant may prevent adequate angiogenesis for bone remodeling.3,5 Blood supply is important for remodeling. Large diameter implants generally have higher removal torque at initial placement and better stability than smaller diameter implants.1 However, the large physical displacement of wide diameter implants may impede bone remodeling. There may be resorption but not apposition.2 There may be a physical barrier for the blood supply that would inhibit apposition but allow resorption to occur.2,6–8Assuming, for the sake of simplicity, a length of 10 mm and the implant is a cylinder, the volume of a 5.7 mm implant is 255.047 cubic mm. The volume of a 2.5 mm × 10 mm implant, again assuming a cylinder, is 49.06 cubic mm. This larger volume may physically impede blood supply and thus impede activity of osteoclasts and osteoblasts thereby impeding remodeling, which in turn may make the cervical supporting bone and epithelial attachment susceptible to peri-implantitis.Occlusal overload is not generally an issue with large diameter implants due to the large surface area. Dental implants are capable of resisting an axial load beyond human capability. Off-axial loads, however, may not be adequately resisted by the facial or lingual cortices depending on bone quality and volume. A large diameter implant spreads any off axial loads over a larger area than small diameter thus lowering the per square millimeter load on the supporting bone.3Mini implants, <3.0 mm in diameter, may demonstrate little or no bone loss over many years of service.9 Nonetheless there is a larger per-square-millimeter load on the supporting bone. Thus control of the off-axial occlusal load is key. Nonetheless, the small surface area puts a larger per-square-millimeter load on the bone. This necessitates more dense bone or multiple splinted implants to lessen the risk for overload on the supporting bone.6–8Percutaneous circumference may put larger diameter implants at risk for peri-implantitis.2,4 Large diameter implants have a much larger percutaneous circumference as compared with small diameter implants. The small diameter/circumference may lessen the risk for late peri-implantitis. At least 1 study suggested that larger diameter implants may be more prone to peri-implantitis.5 The percutaneous circumference of a 5.7 mm implant is 15.7 mm whereas that of a 2.5 mm diameter implant is 7.85 mm, which is a dramatic difference. The smaller circumference presents less of an opportunity for invasive bacteria and less risk for any epithelial detachment and infection. 6–8Impeded remodeling and increased percutaneous exposure may increase the risk for peri-implantitis in large diameter implants. There may be less risk for peri-implantitis with small diameter implants. Large diameter implant fixtures could be more prone to late peri-implantitis. Long-term randomized controlled studies are needed to elucidate this issue. It may be appropriate to only place implants of a diameter to a maximum of 4.7 mm because larger diameters may impede bone remodeling and present a longer percutaneous exposure. It is not known what thickness, volume, or quality of bone is needed to adequately resist a given occlusal load. It may be that small diameter implants may be surprisingly able to survive long-term occlusal loads. Thus, when selecting an implant for a site, it may be better to err on the side of thin.

Maxillary protraction through skeletal anchorage in growing patients. Literature review

Early treatment of skeletal Class III patients is usually handled with the use of maxillary protraction face mask. The results of this orthopedic therapy are often accompanied by adverse dentoalveolar effects. An alternative treatment is skeletal anchorage comprised of temporary anchorage devices (TADs), which uses two titanium plates fixed with mini implants placed in the zygomatic process of the maxilla and two side plates between the lower canine and right and left and the use of intermaxillary elastics. This results in maxillary advancement and improvement of facial aesthetics while reducing dentoalveolar adverse effects.

Stabilization of mandibular complete dentures by four mini implants: Impact on masticatory function

ObjectivesThe frequent instability of mandibular removable complete dentures causes an alteration of mastication. An innovative therapeutic strategy involves placing four symphyseal mini implants. This study aimed at assessing the development of masticatory parameters and the impact on quality of life in subjects that underwent this procedure. MethodsEleven edentulous subjects (mean age 72±11 years) with unstable mandibular complete dentures were followed-up before (T0) and two − three months after (T1) mini implant setting. Physiological parameters (number of cycles, duration of sequence and frequency of mastication) during the mastication of food models and the bolus median particle size (d50) of carrot were evaluated at each time. Quality of life was assessed at T0 and T1 using the Global Oral Health Assessment Index (GOHAI). Parametric tests were used to test relationships between mastication, quality of life variations and mini implant setting, and to compare each parameter mean value at times T0 and T1. ResultsMore subjects were able to chew carrot after setting the mini implants (8 subjects compared to 4 at T0). This improvement was accompanied by changes in kinematic parameters when chewing carrots, soft and hard model food, and by an improvement of their quality of life. However, the particle size values observed in the bolus remained higher than for normal dentate subjects (9.2±2.8mm). ConclusionsThese results indicated that the placement of mini implants as retentive elements for mandibular full dentures had a positive impact on patients’ masticatory function and quality of life. Clinical significanceThe placement of mini implants has a positive impact on the masticatory function and oral health quality of life. The results suggest that this alternative procedure can be used as a treatment option for patients unable to receive conventional implants.

Clinical Outcome of Double Mini Implants versus Single Standard Implant -Supported Crown Replacing Lower Molar

Clinical Outcome of Double Mini Implants versus Single Standard Implant -Supported Crown Replacing Lower Molar

Temporary Anchorage Devices in Bimaxillary Protrusion

Introduction of mini implants in orthodontic treatment mechanics has caused a paradigm shift in the treatment modalities. Mini-screw type of temporary anchorage devices (TADs) are small, placed with a minor surgical procedure and have helped treat complicated as well as borderline surgical cases with relative ease. This case report highlights the use of TADs for the treatment of a 19-year-old female with severe bimaxillary dento-alveolar proclination, protrusive lips and divergent face type. Clinical examination and cephalometric parameters indicated that the case was a critical anchorage case which required extraction of all first premolars. The TADs were placed in all four quadrants between the roots of the second premolar and first molar with the aim of providing absolute anchorage. After retraction of the anterior teeth, fullness of the upper and lower lip has reduced, lip incompetency is eliminated and the severe dentoalveolar proclination is corrected providing absolute anchorage. Clinical Relevance: The treatment of severe bimaxillary dentoalveolar proclination cases with conventional orthodontics has always remained as a challenge; with a greater chance of anchorage loss and inadequate retraction of anteriors into the extraction space resulting in an unsatisfactory treatment result. Use of TADs helps us in implementation of absolute anchorage into the treatment mechanics.

Barriers and facilitators to the implementation of orthodontic mini-implants in clinical practice: a protocol for a systematic review and meta-analysis.

BackgroundMost orthodontic treatment plans need some form of anchorage to control the reciprocal forces of tooth movement. Orthodontic mini implants (OMIs) have been hailed for having revolutionized orthodontics, because they provide anchorage without depending on the collaboration of patients, they have a favorable effectiveness compared with conventional anchorage devices, and they can be used for a wide scale of treatment objectives. However, surveys have shown that many orthodontists never or rarely use them. To understand the rationale behind this knowledge-to-action gap, we will conduct a systematic review that will identify and quantify potential barriers and facilitators to the implementation of OMIs in clinical practice for all potential stakeholders, i.e., patients, family members, clinicians, office staff, clinic owners, policy makers, etc. The prevalence of clinicians that do not use OMIs will be our secondary outcome.MethodsThe Preferred Reporting Items for Systematic review and Meta-Analysis Protocols (PRISMA-P) 2015 Statement was adopted as the framework for reporting this manuscript. We will apply broad-spectrum search strategies and will search MEDLINE and more than 40 other databases. We will conduct searches in the gray literature, screen reference lists, and hand-search 12 journals. All study designs, stakeholders, interventions, settings, and languages will be eligible. We will search studies that report on barriers or facilitators to the implementation of orthodontic mini implants (OMIs) in clinical practice. Implementation constructs and their prevalence among pertinent stakeholders will be our primary outcomes. All searching and data extraction procedures will be conducted by three experienced reviewers. We will also contact authors and investigators to obtain additional information on data items and unidentified studies. Risk of bias will be scored with tools designed for the specific study designs. We will assess heterogeneity, meta-biases, and the robustness of the overall evidence of outcomes. We will present findings in a systematic narrative synthesis and plan meta-analyses when pertinent criteria are met.DiscussionKnowledge creation on this research topic could identify and quantify both expected and unexpected implementation constructs and their stakeholders. Such knowledge can help develop strategies to address implementation issues and redirect future studies on OMIs towards knowledge translation. This could lead to improved patient-health experiences and a reduction in research waste.Electronic supplementary materialThe online version of this article (doi:10.1186/s13643-016-0198-4) contains supplementary material, which is available to authorized users.

A prospective study of factors associated with orthodontic mini-implant survival.

The orthodontic mini-implant (MI) is a widely used anchorage device in orthodontic treatment. This prospective study analyzed MI survival and factors associated with MI survival in 139 patients (114 females and 25 males; average age, 25.7 years; age range, 12-56 years) who had received orthodontic treatment with MIs. Survival analysis and Kaplan-Meier curves were used to identify clinical variables associated with MI survival. For the 254 MIs investigated, the overall success rate was 85.8%, and the 1-year cumulative survival rate was 81.6%. MI survival was significantly associated with patient age and MI size. Notably, MI survival was significantly longer in patients aged 20-30 years than in older patients. The Cox proportional-hazards model revealed a 5% increase in failure risk for every 1-year increase in age among participants older than 30 years. Additionally, MI failure risk was inversely associated with MI length. MIs are generally reliable anchorage devices for orthodontic treatment but should be used with caution in older patients, due to the higher rate of failure in that population. Another important factor in MI survival is implant size. Future studies should attempt to clarify associations between MI survival and clinical variables.(J Oral Sci 58, 515-521, 2016).

Evaluation of Stress Distribution of Mini Dental Implant-Supported Overdentures in Complete Cleft Palate Models: A Three-Dimensional Finite Element Analysis Study

Mini dental implants could be an alternative treatment method for prosthetic treatment of edentulous cleft palate. The aim of this study was to analyze stress distribution around the cortical bone and different plans using a varied number of mini dental implants in edentulous unilateral complete cleft palates. Three edentulous maxillary models were modified to create unilateral complete cleft palates. Mini dental implants (2.4 × 15 mm) were located as two mini implants at the premolar region, four mini implants at the premolar and molar region, and six mini implants at the first premolar, second premolar, and first molar regions in the models, respectively. Mucosa, o-ring/ball attachments, and overdentures were simulated. Vertical and horizontal loads of 100 N were applied on both the right and left molar teeth of the overdenture for each model. Maximum and minimum principal stress values and the distribution at cortical bone around the implants and cleft palates were evaluated by finite element analysis. Stress values under vertical loads were lower than values under horizontal loadings for all models. Stress values were found to be lower in the first model than in the second and third models. The highest stress values were found around implants in the second model. The unilateral feature of a complete cleft pattern affected the stress distribution. Stresses occured mostly around implants when the overdenture was supported by six implants; however, the stress distribution around implants was low with two implants because of tissue support.

Miniscrew implants. An effective means of absolute anchorage.

Bimaxillary dentoalveolar protrusion is the condition characterized by procumbency of lips due to increased protrusion of maxillary and mandibular incisors. This condition can be due to tooth size arch length discrepancy, weak lip musculature unable to withstand strong tongue pressure. This results in severe labial tipping of incisors, which causes upper and lower lip protrusion. This case report describes the treatment of a 21-year old girl with bimaxillary protrusion and convex profile with incompetent lip seal. The treatment of choice for the patient was extraction of four first premolars and utilization of extraction space to reduce the facial convexity by retraction of anterior teeth. The anchorage requirement was maximum for complete correction of facial profile. Mini implants were used to retract the anterior teeth and improve facial aesthetic. Treatment was completed in 20 months. Patient`s facial profile improved significantly with reduced dental protrusion and lip eversion.

Outcome of orthodontic mini-implant loss in relation to interleukin 6 polymorphisms

Mini-implants (MIs) are used increasingly for orthodontic anchorage and their success may require some osseointegration, which is affected by the underlying host immune-inflammatory response. Interleukin 6 (IL-6) is a cytokine expressed during the host response after a trauma or infection. The aim of this study was to investigate the association of clinical characteristics and IL6 tag single nucleotide polymorphisms (which capture the information of the whole gene in terms of genetic variability) with the loss of MIs for orthodontic anchorage. A total of 487 patients were treated with orthodontic MIs between 2004 and 2010. After the application of inclusion and exclusion criteria, the sample comprised 104 patients with one or more MIs that had been in function for at least 6 months with no loss, and 31 patients who had lost one or more MIs. Allele A of rs2069843 and allele T of rs2069849 were suggestively associated with the loss of MIs for orthodontic anchorage and were in complete linkage disequilibrium, which means that one of them is sufficient to capture the same information. The location of installation (mandible) and the number of MIs installed per patient were also associated with the loss of MIs.

Stability of smooth and rough mini-implants: clinical and biomechanical evaluation - an in vivostudy.

Objective: To compare in vivo orthodontic mini-implants (MI) of smooth (machined) and rough (acid etched) surfaces, assessing primary and secondary stability. Methods: Thirty-six (36) MI were inserted in the mandibles of six (6) dogs. Each animal received six (6) MI. In the right hemiarch, three (3) MI without surface treatment (smooth) were inserted, whereas in the left hemiarch, another three (3) MI with acid etched surfaces (rough) were inserted. The two distal MI in each hemiarch received an immediate load of 1.0 N for 16 weeks, whereas the MI in the mesial extremity was not subject to loading. Stability was measured by insertion and removal torque, initial and final mobility and by inter mini-implant distance. Results: There was no statistical behavioral difference between smooth and rough MI. High insertion torque and reduced initial mobility were observed in all groups, as well as a reduction in removal torques in comparison with insertion torque. Rough MI presented higher removal torque and lower final mobility in comparison to smooth MI. MI did not remain static, with displacement of rough MI being smaller in comparison with smooth MI, but with no statistical difference. Conclusions: MI primary stability was greater than stability measured at removal. There was no difference in stability between smooth and rough MI when assessing mobility, displacement and insertion as well as removal torques.

Finite Element Analysis of Bone Stress for Miniscrew Implant Proximal to Root Under Occlusal Force and Implant Loading.

Because of the narrow interradicular spaces and varying oral anatomies of individual patients, there is a very high risk of root proximity during the mini implants inserting. The authors hypothesized that normal occlusal loading and implant loading affected the stability of miniscrew implants placed in proximity or contact with the adjacent root. The authors implemented finite element analysis (FEA) to examine the effectiveness of root proximity and root contact. Stress distribution in the bone was assessed at different degrees of root proximity by generating 4 finite element models: the implant touches the root surface, the implant was embedded in the periodontal membrane, the implant touches the periodontal surface, and the implant touches nothing. Finite element analysis was then carried out with simulations of 2 loading conditions for each model: condition A, involving only tooth loading and condition B, involving both tooth and implant loading. Under loading condition A, the maximum stress on the bone for the implant touching the root was the distinctly higher than that for the other models. For loading condition B, peak stress areas for the implant touching the root were the area around the neck of the mini implant and the point of the mini implant touches the root. The results of this study suggest that normal occlusal loading and implant loading contribute to the instability of the mini implant when the mini implant touches the root.

Mini vs. Standard Implants for Mandibular Overdentures

A mandibular implant-retained overdenture is considered a first-choice treatment for edentulism. However, some aspects limit the use of standard implants—for example, the width of edentulous ridges, chronic diseases, fear, or costs. This randomized trial compared mandibular overdentures retained by 2 or 4 mini-implants with standard implants, considering oral health–related quality of life (OHRQoL), patient satisfaction, and complications such as lost implant. In sum, 120 edentulous men and women (mean age, 59.5 ± 8.5 y) randomly received 4 mini-implants, 2 mini-implants, or 2 standard implants. Participants provided data regarding OHRQoL and satisfaction until 12 mo. Clinical parameters, including implant survival rate, were also recorded. Both 2 and 4 mini-implants led to better OHRQoL, compared with 2 standard implants. Treatment with 4 mini-implants was more satisfying than 2 standard implants, with 2 mini-implants presenting intermediate results. Implant survival rate was 89%, 82%, and 99% for 4 mini-implants, 2 mini-implants, or 2 standard implants, respectively. Overdentures retained by 4 or 2 mini-implants can achieve OHRQoL and satisfaction at least comparable with that of 2 standard implants. However, the survival rate of mini implants is not as high as that of standard implants (ClinicalTrials.gov NCT01411683).