Immediate Loading Group Research Articles

Aesthetic Outcome and Patient Perception of Immediate vs. Delayed Loading of Implant-Supported Single Crowns: A Randomized Controlled Trial

ABSTRACT Background: This randomized controlled trial aimed to compare the aesthetic outcome and patient perception of immediate versus DL of implant-supported single crowns. Methods: A total of 60 patients with a single missing tooth were enrolled and randomly assigned to two groups: immediate loading (IL) and delayed loading (DL). Each group consisted of 30 patients with a total of 30 implants. In the IL group, crowns were loaded onto implants immediately after placement, while in the DL group, a healing period of 3 months was observed before crown placement. Aesthetic outcome was assessed using the Pink Esthetic Score (PES) for soft tissue and the White Esthetic Score (WES) for the crown. Patient perception was evaluated through a visual analog scale (VAS) for satisfaction, comfort, and overall experience. Results: The IL group demonstrated comparable aesthetic outcomes to the DL group, with mean PES and WES scores of 10.2 ± 1.5 and 8.7 ± 1.2, respectively, in the IL group, and 10.5 ± 1.3 and 8.5 ± 1.4 in the DL group. Patient perception in terms of satisfaction, comfort, and overall experience was similarly high in both groups, with VAS scores above 8 for each parameter. Conclusion: This randomized controlled trial suggests that both IL and DL of implant-supported single crowns result in favorable aesthetic outcomes and high levels of patient satisfaction.

Immediate versus conventional loading of mandibular implant-retained overdentures: a 3-year follow-up of a randomized controlled trial.

There is a scarcity of randomized clinical trials (RCT) that report medium- and long-term results and a lack of consensus in the literature on the predictability of immediately loaded unsplinted narrow diameter implants supporting mandibular overdentures. This RCT compared the performance of conventional (CL) and immediate loading (IL) of mandibular overdentures retained by two narrow-diameter implants for 3years. Patients from an RCT treated with CL or IL were invited to attend to 2- and 3-year follow-ups. Clinical, radiographic, functional, and oral health-related quality of life parameters were evaluated. Prosthetic maintenance events, biological complications, and success and survival rates were also recorded. The data were tested by multilevel mixed-effects linear regression analysis and chi-squared tests. The 1-year survival rates of 90% in the CL group and 85% in the IL group were maintained as no implants were lost between 1 and 3years. The marginal bone loss (MBL) in the IL group was significantly lower after year 3 (-0.04; p < 0.01). Significant changes were found only for the intra-group comparisons in the third year of function: (i) CL and IL presented similar progression of implant stability, MBL, and posterior bone area resorption; (ii) while CL started deteriorating of masticatory function, IL still exhibited functional evolution and (iii) oral comfort domain in the CL and pain domain in the IL were improved. Although IL experienced the lowest MBL after 3years, the outcomes showed that both loading protocols result in predictable medium-term rehabilitation when monitored annually. It can be expected that in the third year of function, patients with immediate loading may present more complaints related to general performance even with acceptable masticatory function and self-reported improvements in oral comfort.

Cumulative success rate and marginal bone loss for immediate and early loading protocols in a single implant-supported crown: A randomized controlled split-mouth clinical trial

Statement of problemNew loading protocols with reduced treatment time have gained popularity because of their advantages. However, whether the success rate with immediate loading (IL) is worse than with early loading (EL) is still unclear. PurposeThe purpose of this randomized controlled trial with a split-mouth design was to evaluate the marginal bone loss and the cumulative success rate (CSR) 1 year after an IL protocol in single implant-supported crowns. The test groups were loaded after less than 24 hours (test group) and EL at 60 days (control group). Material and methodsSeventeen participants received 34 implants. The recall appointments were at baseline, 30 days, 60 days, and 1 year. The outcome measures evaluated were pain, implant clinical mobility, probing depth measurements, peri-implant disease, marginal bone loss, implant insertion torque, implant stability quotient (ISQ) value, and the CSR. A 2-way repeated measures ANOVA identified the significant differences for probing depth and ISQ. A 3-way repeated measures ANOVA followed by a pairwise t test analyzed marginal bone loss, and a nonparametric Wilcoxon test analyzed insertion torque (α=.05). ResultsNo differences were found between the insertion torque, ISQ, and marginal bone loss values (P>.05). When analyzing probing depth, no differences were found when comparing IL versus EL at baseline, 30 days, and 1 year (P>.05). The global CSR was 91.17%, 88.23% for the IL group and 94.11% for the EL group. ConclusionsWhen analyzing marginal bone loss, the groups were similar. The global CSR was 91.17%, 88.23% for the IL group, and 94.11% for the EL group.

Immediate loading protocols increase the risk of failure of implants placed by fully guided surgery in partially edentulous jaws: A randomized clinical trial.

To compare the 1-year outcomes of immediate loading (IL) and delayed loading (DL) protocols for implants placed by fully guided surgery in partially edentulous jaws. This study included 72 patients who received implant surgery with either IL (93 implants, 36 patients) or DL (94 implants, 26 patients). A prefabricated provisional prosthesis was delivered immediately for the IL group (86 implants, 32 patients) with the exception of 4 subjects in whom an initial torque of >20 Ncm and an implant stability quotient of >65 were not achieved, while all DL-group implants were loaded after 3months. The 1-year implant survival rate estimated by intention-to-treat (ITT) and per-protocol (PP) analyses, and the marginal bone loss (MBL) estimated by cone-beam computed tomography were statistically evaluated (p < 0.05). The survival rate in the DL group was 100% at both patient and implant levels. With only 26 subjects with 78 implants surviving in the IL group, the survival rates were 69.4% and 83.4% at the patient and implant levels, respectively, in the ITT analysis, and 78.1% and 90.2% in the PP analysis. All intergroup differences in survival rates were statistically significant (p < 0.01). MBL was less than 0.1 mm in both groups (p > 0.05). IL for implants placed by fully guided surgery in the partially edentulous jaws increased the probability of failure compared to 3-month DL. Regardless of when loading occurred, marginal bone levels remained stable.

Masticatory performances and maximum occlusal forces of immediate and conventional loaded two-implant supported overdentures retained by magnetic attachments: preliminary study of randomized controlled clinical trial

BackgroundThe appropriate loading protocol to improve masticatory performance (MP) is still unclear in elderly patients and two-implant overdentures (2-IODs) wearers. This study aimed to compare the long-term MP and maximum occlusal force of immediate loading (IL) and conventional loading (CL) of 2-IODs retained by magnetic attachments. Nineteen edentulous patients were randomly assigned to either an IL (n=10) or CL group (n = 9). In the IL group, the implant was loaded on the same day as insertion, whereas it was loaded 3 months after insertion in the CL group. Magnetic attachments were used to retain all overdentures to the implants. MP, measured by a piece of color-changeable chewing gum and a gummy jelly test, and maximum occlusal force, measured using an occlusal force measuring device, were assessed in both groups at baseline and at 3-, 4-, and 5-year follow-ups.ResultsNo significant differences were observed in the MP and the maximum occlusal force between the IL and CL groups at any time point. However, a significantly higher MP was observed at the 3-year time point in the IL group (P = 0.036). The maximum occlusal force revealed a significant correlation with MP, both with the color-changeable chewing gum and gummy jelly at 5 years.ConclusionAfter long-term observation, no significant differences in MP and maximum occlusal force were observed between the IL and CL groups. However, compared to pre-implant insertion of the complete denture, the MP in the IL group significantly improved at 3 years. Furthermore, the maximum occlusal force was significantly correlated with MP at 5 years.Trial registrationUMIN, UMIN000009889. Registered on 28 January 2013.

Immediate Loading of Single Implants, Guided Surgery, and Intraoral Scanning: A Nonrandomized Study.

To compare clinical and esthetic outcomes between immediately loaded single implants placed with and without a fully guided surgical procedure. Patients with a missing maxillary tooth (second premolar to second premolar) were considered for inclusion in this 1-year prospective nonrandomized study. Exclusion criteria were general health contraindications for oral surgery besides the need for bone grafting or ridge augmentation. One group received digital implant planning, fully guided surgery, and immediate loading (DIL). The other group received freehand surgery and immediate loading (IL). Outcome measures were implant survival, marginal bone loss, soft tissue changes, papilla index, pink and white esthetic scores (PES and WES, respectively), and patient-reported outcome measures (PROMs). Two of 21 implants failed in the DIL group soon after placement, resulting in a 1-year implant survival rate of 90.5%, while no implants failed in the IL group. Significantly higher papilla index scores and lower soft tissue changes were found for the DIL group compared to the IL group. No differences were found after 1 year regarding marginal bone loss, PES, WES, or PROMs. Within the limitations of this study, immediate loading in combination with fully guided surgery might negatively affect implant survival. Immediate loading, fully guided surgery, and a digital workflow appear to have a positive effect on early soft tissue adaptation.

Immediate vs conventional loading of Facility-Equator system in mandibular overdenture wearers: 1-year RCT with clinical, biological, and functional evaluation.

The use of immediate loading (IML) is still poorly explored in elderly patients and implant-retained mandibular overdenture (IMO) wearers. For this reason, more comparisons to conventional loading (CL) are required. To evaluate the clinical, biological, functional, and oral health-related quality of life (OHRQOL) influence of CL and IML loading on elders wearing IMO retained by the Facility-Equator system up to 1 year after implant installation. Twenty edentulous patients received two narrow diameter implants in the mandible; the loading type (CL or IML) was randomized. The clinical parameters were monitored along with prosthetic events, marginal bone loss (MBL) and bone level change (BLC), implant stability quotients (ISQ), masticatory performance outcomes, and Interleukin 1 beta (IL-1β) and tumor necrosis factor alpha (TNF-α) levels in the peri-implant crevicular fluid during the first year of loading. The OHRQoL was assessed via the Oral Health Impact Profile-EDENT questionnaire. Data were analyzed by the Mann-Whitney, χ2 , Wilcoxon paired, and McNemar tests. After 1 year, MBL, BLC and ISQ were statistically identical (P > .05) in the CL and IML groups. The probing depth at 12 months in the CL group (2.19 mm) was higher than in the IML group (1.29 mm; P ≤ .0001). TNF-α was 33.6% higher in the CL group at 6 months (P = .043), while IL-1β was significantly higher in the IML group up to 6 months. The survival rate was 90% in the CL group and 85% in the IML group; 33 prosthetic events occurred in CL group and 23 in IML group. After 12 months, both loading protocols are viable and result in similar clinical, biological, functional, and OHRQOL outcomes. However, IML generates better adaptation of the peri-implant tissues, faster improvement in OHRQoL and fewer prosthetic intercurrences than CL.

Peri‐implant myelinated nerve fibers: Histological findings in dogs

While osseointegration following various dental implant placement protocols has been extensively investigated, the neurohistological integration has received little attention. The primary aim of this study was to compare the myelinated nerve fibers density in peri-implant bone tissue following various implant placement protocols. The secondary aim assessed the effect of follow-up on peri-implant nerve fibers density. Ten beagle dogs randomly received 68 commercially pure titanium implants in the mandibular premolar or molar regionbilaterally following extraction utilizingone of the six treatment protocols: (a) immediate implant placement (IIP) and immediate loading (IL); (b) IIP and delayed loading (DL); (c) IIP and left unloaded (UL); (d) delayed implant placement (DIP) and IL; (e) DIP and DL; and (f) DIP and UL. Histomorphometric analysis of the peri-implant myelinated nerve fibers was performed in a 300μm peri-implant zone at the cervical, middle, and apical level following implant placement. The follow-up assessment involved longitudinal observation at 3months following each implant treatment protocol and at 6months for IIP+IL and IIP+DL protocols. The influence of different treatment protocols, including the fixed effects of implant groups (IIP+IL, IIP+DL, IIP+UL, DIP+IL, DIP+DL, DIP+UL) and regions (cervical, middle, apical), was examined via a linear mixed model. The IIP+IL group showed a significantly higher myelinated nerve density compared to the IIP+UL and DIP+UL group. Peri-implant nerve re-innervation was significantly higher (P=.002) in the apical region compared to the cervical region. After immediate implant placement, the IL group showed a significantly (P=.03) higher density of myelinated nerve fibers compared to DL. No significant (P=.19) effect of follow-up on nerve density was observed. The immediate implant placement and loading protocol showed most beneficial effect on peri-implant innervation with highest myelinated nerve density in the apical region. A longer loading time had no influence on the peri-implant nerve density.

Tightening and Loosening of the Abutment Screw Negatively Affects Implant Osseointegration in the Early Healing Stage in Rat Tibiae.

To examine the effect of tightening and loosening the dental implant screw on implant osseointegration in an elderly rat model. Titanium dental implants were inserted in the bilateral tibiae of 34 elderly Wistar rats (1 year and 3 months old). Rats were randomly divided into five groups: control (no loading); immediate loading (IL) (vertical load [3 Hz for 15 minutes/day] immediately after implantation); early loading (EL) (load started on postoperative day 7); five times abutment removal (R5) (tightening and loosening of the abutment screw once per day for 5 days each week); and two times abutment screw removal (R2) (tightening and loosening of the abutment screw once per day for 2 days each week). After 4 weeks, the rats were euthanized, and the bone structure surrounding the dental implants was evaluated using microcomputed tomography analysis. Osseointegration failed more frequently in the EL, R2, and R5 groups than in the control and IL groups (P = .06). The EL, R2, and R5 groups also tended to have lower relative gray values than the control and IL groups. Tightening and loosening the abutment screw might negatively affect dental implant osseointegration in the early healing stage in older adults.

Healing differences in narrow diameter implants submitted to immediate and conventional loading in mandibular overdentures: A randomized clinical trial.

Biological responses to different loading protocols during the bone healing phase in subjects with long time since edentulism, rehabilitated with narrow diameter implants (NDIs) to retain mandibular overdentures (MOs), are still unavailable. This randomized clinical trial compared the peri-implant health, implant stability, and concentrations of pro- and anti-inflammatory cytokines in the peri-implant crevicular fluid (PICF) in mandibular edentulous patients under conventional (CL) and immediate loading (IML) during healing. Twenty totally edentulous patients received two NDIs (2.9×10mm, Facility NeoPoros) placed in mandible anterior region and were randomly assigned to two loading protocols: CL (n=10) and IML (n=10). The following clinical outcomes were evaluated 1, 2, 4, 8, and 12weeks after surgery: (a) peri-implant tissue health (gingival index-GI, plaque index-PI, calculus-presence CP, probing depth-PD, and bleeding on probing-BOP); (b) implant stability quotient (ISQ); and (c) IL-1β, IL-6, IL-10, and TNF-α levels in the PICF analyzed by ELISA. The CL group showed significantly higher CP scores at weeks 8 and 12. The IML group showed significantly higher GI from the first week onwards. The IML group presented significantly lower PD at all follow-up times, and higher BOP rates than CL at week 12. The ISQ values of the CL group were higher than those of the IML group, except at week 4. The IML group released significantly more TNF-α between weeks 1 and 4 and more IL-1β during week 4-12, while releasing less IL-6 until week 8, mainly at week 2 (-47.6%). The release of IL-10 was similar for both groups and increased progressively over time. At week 12, the IML group released 45.74% more IL-10 than the CL group. The survival rates were 95% and 90% for CL and IML, respectively. The IML group presented more favorable PD at all evaluation times; the differences between the other clinical parameters were less systematic. The implant stability and the inflammatory marker concentrations were more stable in the CL group.

Clinical and Radiographic Assessment of Three-Implant-Supported Fixed-Prosthesis Rehabilitation of the Edentulous Mandible: Immediate Versus Delayed Loading.

To evaluate and compare the clinical and radiographic outcomes of mandibular rehabilitation with fixed prostheses on three implants with immediate versus delayed loading. The sample comprised 21 patients who underwent treatment with immediate loading and 23 who received delayed loading. All had worn their prostheses for at least 18 months. Radiographic evaluation of bone loss was carried out in Adobe Photoshop CS5 by a single calibrated examiner using digitized panoramic radiographs. Clinical examination of the technical conditions of the prosthetic device assessed the condition of the acrylic resin base, dental occlusion, metal framework, presence of cover screws, screw fixation of the prosthesis and abutments, length of cantilever (effort) and resistance arms, presence of plaque on prosthetic abutments, and hygiene of the prosthesis. One implant failed in each group, resulting in a 95.23% treatment success rate with immediate loading and 95.65% with delayed loading (no statistically significant between-group difference). In the immediate-loading group, the mean bone loss was 1.96 ± 0.73 mm around central implants and 1.64 ± 0.84 mm at distal implants. In the delayed-loading group, the mean bone loss was 1.85 ± 0.67 mm around central implants and 1.70 ± 0.77 mm at distal implants. According to Student t test, there was no significant within-group difference in bone loss and no difference between the immediate-loading and delayed-loading groups. The only prosthesis-related complications that differed significantly between groups were "condition of the acrylic base," "occlusion," and "presence of right cover screw." There was no statistically significant association of lever arm ratio with peri-implant bone loss or bone loss on the mesial surfaces compared to the distal surfaces of the distal implants. The three-implant-supported fixed prosthesis protocol tested in this study proved to be a viable therapeutic strategy for mandibular edentulous patients with maxillary complete dentures, regardless of whether loading was immediate or delayed, with no difference in peri-implant bone loss.

Immediate and delayed loading of two-piece reduced-diameter implants with locator-analog attachments in edentulous mandibles: One-year results from a randomized clinical trial examining clinical outcome and patient expectation.

Prosthetic management of thin alveolar ridges in the edentulous mandibles of elderly patients, especially the time of loading, the number of implants needed, and patient expectations and perception, is a challenge in implant dentistry. Survival of conventionally and immediately loaded 2-piece reduced-diameter implants in the interforaminal region of the edentulous mandible supporting locator-analog attachments was evaluated. Prosthetic complications and peri-implant hygiene were also studied, and patient expectation and subjective evaluation of the treatment were documented. Twenty-five patients with adapted complete dentures received 4 reduced-diameter implants. All anterior implants were immediately loaded. Three months later, patients were allocated by randomization to 1 of 2 treatment groups: 2 locator-analog attachments on the anterior implants (Group A); or 4 locator-analog attachments (Group B). After another 3 months patient allocation was changed (crossover design) for the next 3 months. Questionnaires with Likert scales and numeric rating scales were used to assess patients' expectations and subjective overdenture-related variables, respectively. One implant was lost in the immediate-loading group. Survival was 98% and 100% for immediate and delayed loading, respectively. During 12-month observation, 8 complications required aftercare. At the beginning of treatment, patients' expectations were highly positive. Subjective assessment of overdenture-related variables 3 months after immediate loading of 2 implants revealed a statistically significant improvement for most of the variables studied; this was maintained 1 year later. In the subjective assessments, there were no statistically significant differences between Groups A and B. Immediate loading of reduced-diameter implants supporting locator-analog attachments resulted in high implant survival, few prosthetic complications, good oral hygiene, and improvement of subjective denture perception in the short-term. It might be a promising treatment option, especially for elderly patients with a narrow mandibular ridge.

Clinical and radiographic outcome following immediate loading and delayed loading of single-tooth implants: Randomized clinical trial.

Immediate loading of single implants is generally considered a reliable procedure. The objective of the present prospective randomized clinical study was to compare the overall treatment outcome following immediate loading (IL) and delayed loading (DL) of single implants after 1 year of follow-up. Patients with a missing maxillary tooth (15-25) were randomly assigned to IL or DL. The protocol included implant installation in healed sites, immediate loading, delayed loading, temporary screw-retained restoration, and replacement with a permanent single implant crown. Outcome measures were implant survival, marginal bone level, soft tissue changes, papillae index, pink, and white esthetic score (PES and WES), patient judged aesthetics, and oral health impact profile (OHiP-14). Implant survival rate was 100% and 96% for IL and DL, respectively. Implant success rate was 96% and 88% for IL and DL, respectively. Statistically significant lower papilla index scores were found in the IL group at temporary crown and definitive crown placement. An overall statistically significant improvement after 12 months for PES, WES and OHIP-14 was found. This prospective randomized study showed that single implants in the maxilla can present satisfactory results with respect to either immediate loading or delayed loading after 12 months.

Evaluation of peri-implant bone metabolism under immediate loading using high-resolution Na18F-PET.

This study aimed to examine the influence of immediate loading on the dynamic changes of bone metabolism around dental implants using a high-resolution semiconductor sodium 18F-fluoride (Na18F)-PET. Tibiae of 12 adult male rats were divided into 4 groups: immediate loading (IL), no loading (NL), bone defect (BD), and control (CTR). For the IL group, a 4.0-N load was applied continuously by two closed-coil springs attached between two implants in tibia. Each rat received an intravenous injection of Na18F and was scanned by high-resolution Na18F-PET at day 1 and then at weeks 1, 2, 3, 4, 5, 6, and 8 after surgery. Bone metabolism around the implant was evaluated by standardized uptake value (SUV), which indicates the outcome of Na18F accumulation. CT scanning was also performed, and PET and CT images were superposed to determine the anatomical orientation in PET images. Bone metabolism peaked at 7days after surgery and then gradually decreased in all three test groups (IL, NL, and BD). SUVs of all three test groups were significantly higher than the baseline at 1, 2, 3, and 4weeks after surgery, with SUVs in the IL group returning to baseline levels earlier than those in the NL and BD groups. Fluorine integrates preferentially with the initial low-calcified bone; thus, our results suggest that immediate loading promotes the calcification of the bone tissue in the early stage on peri-implant bone formation. Na18F-PET allows for an estimate of bone metabolism change around the implant.

Enhancement of Orthodontic Anchor Screw Stability Under Immediate Loading by Ultraviolet Photofunctionalization Technology.

Ultraviolet (UV)-mediated photofunctionalization technology is intended to enhance the osseointegration capability of titanium implants. There are concerns about orthodontic anchor screws loosening under immediate loading protocols in adolescent orthodontic treatment. The purpose of this in vivo study was to evaluate the effects of photofunctionalization on the intrabony stability of orthodontic titanium anchor screws and bone-anchor screw contact under immediate loading in growing rats. Custom-made titanium anchor screws (1.4 mm in diameter and 4.0 mm in length) with or without photofunctionalization pretreatment were placed on the proximal epiphysis of the tibial bone in 6-week-old male Sprague-Dawley rats and were loaded immediately after placement. After 2 weeks of loading, the stability of the anchor screws was evaluated using a Periotest device, and the bone-anchor screw contact ratio (BSC) was assessed by a histomorphometric analysis using field-emission scanning electron microscopy. In the unloaded group, Periotest values (PTVs) were ~25 for UV-untreated screws and 13 for UVtreated screws (P < .01), while in the immediate-loading group, PTVs were 28 for UV-untreated screws and 16 for UV-treated screws (P < .05). Significantly less screw mobility was observed in both UV-treated groups regardless of the loading protocol. The BSC was increased ~1.8 fold for UV-treated screws, compared with UV-untreated screws, regardless of the loading protocol. Photofunctionalization enhanced the intrabony stability of orthodontic anchor screws under immediate loading in growing rats by increasing bone-anchor screw contact.

Effect of immediate and delayed high-strain loading on tendon-to-bone healing after anterior cruciate ligament reconstruction.

We previously demonstrated, in a rat anterior cruciate ligament (ACL) graft reconstruction model, that the delayed application of low-magnitude-strain loading resulted in improved tendon-to-bone healing compared with that observed after immediate loading and after prolonged immobilization. The purpose of this study was to determine the effect of higher levels of strain loading on tendon-to-bone healing. ACL reconstruction was carried out in a rat model in three randomly assigned groups: high-strain daily loading beginning on either (1) postoperative day one (immediate-loading group; n = 7) or (2) postoperative day four (delayed-loading group; n = 11) or (3) after prolonged immobilization (immobilized group; n = 8). Animals were killed two weeks after surgery and micro-computed tomography (micro-CT) and biomechanical testing of the bone-tendon-bone complex were carried out. The delayed-loading group had greater tissue mineral density than either the immediate-loading or immobilized group (mean [and standard deviation], 813.0 ± 24.9 mg/mL compared with 778.4 ± 32.6 mg/mL and 784.9 ± 26.4 mg/mL, respectively; p &lt; 0.05). There was a trend toward greater bone volume per total volume fraction in both the immobilized and the delayed-loading group compared with the immediate-loading group (0.24 ± 0.03 and 0.23 ± 0.06 compared with 0.20 ± 0.05; p = 0.06). Trabecular thickness was greater in the immobilized group compared with the immediate-loading group (106.5 ± 23.0 μm compared with 72.6 ± 10.6 μm; p &lt; 0.01). There were no significant differences in failure load or stiffness between the immobilized group and either high-strain cyclic-loading group. Immediate application of high-strain loading appears to have a detrimental effect on healing in this rat model. Any beneficial effects of delayed loading on the healing tendon-bone interface (after a brief period of immobilization) may be offset by the detrimental effects of excessive strain levels or by the detrimental effects of stress deprivation on the graft. The timing and magnitude of mechanical load on a healing rat ACL reconstruction graft may have important implications for postoperative rehabilitation. Avoidance of exercises that cause high graft strain in the early postoperative period may lead to improved tendon-to-bone healing in humans.

A healing period increases mini-implant stability in growing rats.

We assessed the stability of orthodontic mini-implants in young rats. Male rats with mean ages of 6 weeks (n = 16) and 20 weeks (n = 16) were divided into four groups (n = 8 each). In the 6- and 20-week immediate-loading groups, immediately after placement, mini-implants were exposed to an experimental traction force for 2 weeks. In the 6- and 20-week healing groups, the force was applied for 2 weeks after a 6-week healing period. Right tibiae served as the test limbs and the left tibiae as controls. A Periotest device was used to measure mini-implant mobility after traction, and Tukey's test was used to compare Periotest values among groups. The results showed significantly greater mobility in the 6-week immediate-loading group than in the 20-week immediate-loading and 6- and 20-week healing groups, and significantly less mobility in the 6-week healing group than in the 20-week immediate-loading group (P < 0.05). Mini-implants were stable during the healing period. The results indicate that mini-implants can be used for orthodontic anchorage in juvenile patients if the duration of healing is sufficient.

Influence of immediate and early loading on bone metabolic activity around dental implants in rat tibiae

The aim of this study was to examine the influence of immediate and early loading on dynamic changes in bone metabolism around dental implants using bone scintigraphy. Two titanium implants were inserted in the right tibiae of 21 rats. Closed coil springs with 4.0-N loads were applied parallel to the upper portion of the implants for 35days. According to the load application timing, rats were divided into three groups: immediate loading (IL) group, early loading 1day after implant insertion (1-D early loading [EL]) group, and loading 3days after implant insertion (3-D EL) group. Rats were intravenously injected with technetium-99m-methylene diphosphonate (Tc99m-MDP) (74 MBq/rat) and scanned by bone scintigraphy at 1, 4, 7, 11, 14, 21, 28, and 35days after load application. The ratio of accumulation of Tc99m-MDP around the implants to that of a reference site (uptake ratio) was calculated to evaluate bone metabolism. In every group, the uptake ratio increased until 7days after load application and then gradually decreased. It was significantly higher than baseline at 4, 7, 11, and 14days (P<0.001). The uptake ratio in the 1-D EL and 3-D EL groups were significantly higher than that in the control group and also that in the IL group (P<0.001). Bone metabolism initially increased and then gradually decreased to baseline despite differences in load timing. Increases in bone metabolic activity differed according to load application timing; the later the load application, the more enhanced the bone metabolism.

A 10-Year Retrospective Clinical Evaluation of Immediately Loaded Tapered Maxillary Implants

The aim of this study was to compare the effects of immediate loading (IL) and delayed loading (DL) on peri-implant crestal bone loss around maxillary implants after long-term functioning. A retrospective chart review was conducted to assess the outcomes of 110 tapered, multithreaded implants placed for the treatment of one or more missing and/or unsalvageable teeth in the maxilla of 23 patients. Implants were assigned to either the DL or IL database according to loading time. Marginal bone changes were calculated using standardized radiographs taken at implant placement (baseline) and during annual follow-ups. One implant failed in the DL group. After a mean follow-up of 111 months in the DL group and 119 months in the IL group, cumulative implant survival was 99.09% (DL = 98.11%, IL = 100%). No observable bone loss was evident in 83.49% of the surviving implants. Cumulative success rates were 100% for the IL group and 98.11% for the DL group. Immediately loaded maxillary implants showed long-term results comparable to delayed loaded maxillary implants.

Indikationsspektrum von Gaumenimplantaten bei früh- und spätbelasteten Behandlungskonzepten

To analyze the spectrum of indications for second-generation palatal implants in relation to two different loading concepts in a prospective, multicenter, randomized controlled trial (RCT). Forty-one patients were recruited to the study from 2006 to 2009. All implants (Orthosystem, Straumann, Basel, Switzerland; dimensions: 4.1 mm x 4.2 mm) were inserted in the median or paramedian region of the anterior palate, and each patient was randomized to one of two loading groups (immediate loading within the first week after insertion versus conventional loading after a 12-week healing phase). In this interim evaluation, we report preliminary results obtained six months after functional loading. All palatal implants were primarily stable at the time of insertion. One implant loss (12 weeks after surgical insertion) was documented in the cohort subjected to conventional loading, and one patient dropped out of the immediate-loading group. At the time of this investigation, 39 palatal implants are experiencing functional loads. Using both loading concepts, we had various orthodontic objectives, such as intrusion of anterior and/or posterior teeth, and the mesialization and distalization of posterior teeth. Both loading groups presented nearly identical indications, and the distribution of direct vs. indirect anchorage forms was also very similar during the active treatment. Comparison of the two treatment concepts revealed no clinical differences in implant stability. Patients undergoing immediate-loading therapy were subject to no limitations regarding indications at 6 months after functional loading compared with the patients who experienced conventional loading.