Immediate loading at single crowns and 2-unit bridges supported by implants installed in a healed alveolar bony ridge or immediately after tooth extraction. An experimental study in dogs.

To evaluate presumptive differences in osseointegration at implants installed in healed sites or extraction sockets, supporting either crowns or bridges that were functionally loaded or left unloaded. In six dogs, the mesial roots of the first mandibular molars were treated endodontically. Bilaterally, the teeth were hemisected, and the distal roots extracted. First and second mandibular premolars were extracted as well. After 3 months, the mandibular third and fourth distal roots were extracted after endodontic treatment of the mesial roots. Four implants were installed bilaterally, two in the healed sites corresponding to the second premolar and first molar regions, and two into the extraction sockets. Cobalt-chrome single crowns were prepared and installed in the two most anterior implants, and bridges at the two most posterior implants, bilaterally. A 3-unit bridge was applied to the premolars in the upper jaw only at the loaded sites. All prostheses had a flat occlusal surface and contacts in centric occlusion only at the loaded sites. Three months later, biopsies were retrieved for histological analysis. Higher levels of osseointegration and bone density were observed at the unloaded sites, both at implants installed in healed and post-extraction sites. However, only at implants installed in the post-extraction sites and supporting single crowns, the difference in bone-to-Implant contact was statistically significant. In implant installation immediately following extraction or delayed after three months, osseointegration and bone density were not affected by occlusal contact schemes.

Radiographic evaluation of immediately loaded implants supporting 2-3 units fixed bridges in the posterior maxilla: a 3-year follow-up prospective randomized controlled multicenter clinical study.

OBJECTIVE: To compare the survival rate and alveolar bone levels at implants installed in healed sites and functionally loaded within 1 h from installation or after 3 months. MATERIAL AND METHODS: A total of 30 patients (17 male and 13 female) were recruited and 71 implants with a SLA(®) surface, 4.1 mm in diameter and 8-12 mm long, were installed in a fully healed alveolar ridge, 36 as test and 35 as control implants. The test implants were immediately loaded with a temporary reconstruction in proper occlusion, while the randomly selected control sites received the final reconstruction after 3 months. Radiographic bone levels were determined after implant installation, prosthesis delivery, and at annual intervals thereafter. RESULTS: One patient of the control and one patient of the test were excluded from evaluation. No further losses of implants or patients were seen up to the 3-year follow-up. Hence, data from 28 patients were accounted for. A total of 37 and 36 metal-ceramic crowns were provided at the test and control sites, respectively. No biological and technical complications were observed during the 3-year follow-up. Bone levels at the time of implant installation were at 1.6 ± 0.8 and 1.7 ± 0.9 mm from the implant shoulder at the test and control sites, respectively. At prosthesis delivery, the bone levels were located at 2.4 ± 0.7 mm at the control sites 3 months after implant placement. After 1 year of function, similar bone levels were observed at both sites, displaying 2.4 ± 1.0 and 2.5 ± 0.8 mm at the test and control sites, respectively. No differences were found in the subsequent observation periods. CONCLUSION: Survival rates and radiographic bone levels after 1, 2, and 3 years of observation did not differ between conventionally installed implants loaded immediately or delayed (after 3 months). Moreover, insertion torque values did not affect osseointegration.

Use of short implants (6 mm) in a single-tooth replacement: a 5-year follow-up prospective randomized controlled multicenter clinical study.

OBJECTIVE: To evaluate prospectively clinical and radiographic outcomes of 6- or 10 mm-long implants with moderately rough surface (SLA(®) ) loaded within 7 weeks from installation and supporting single crowns in the posterior regions in the course of 5 years of loading. MATERIAL AND METHODS: Sixty implants with a moderately rough surface, 30 tests (6 mm long, 4.1 mm in diameter) and 30 controls (10 mm long, 4.1 mm in diameter), were placed in posterior regions in 45 patients. After 6 weeks, impressions were taken and the implants were restored with a single fixed prosthesis made with gold-palladium alloy and porcelain. Survival rate and marginal bone loss were evaluated yearly. The clinical crown/implant ratio was calculated. RESULTS: During the follow-up period, five implants, four tests and one control, were lost. Of the four test implants, one was lost before loading, two between the 2nd and the 3rd years, and one during the 4th year of the follow-up period. The control implant was lost during the first year of function. Consequently, after 5 years of follow-up, a survival rate of 86.7% and 96.7% was observed at the test and control sites, respectively. CONCLUSION: The results of this study showed that 6-mm-long implants supporting single crowns loaded within 7 weeks from installation lose a small amount of marginal bone during 5 years of functional loading, similar to that of 10-mm-long implants. However, a higher degree of implant loss was recorded at the short implants, probably due to the fracturing of the surrounding bone.

Sub-crestal positioning of implants results in higher bony crest resorption: an experimental study in dogs.

OBJECTIVE: To compare peri-implant soft- and hard-tissue integration at implants installed juxta- or sub-crestally. Furthermore, differences in the hard and soft peri-implant tissue dimensions at sites prepared with drills or sonic instruments were to be evaluated. MATERIAL AND METHODS: Three months after tooth extraction in six dogs, recipient sites were prepared in both sides of the mandible using conventional drills or a sonic device (Sonosurgery(®)). Two implants with a 1.7-mm high-polished neck were installed, one with the rough/smooth surface interface placed at the level of the buccal bony crest (control) and the second placed 1.3 mm deeper (test). After 8 weeks of non-submerged healing, biopsies were harvested and ground sections prepared for histological evaluation. RESULTS: The buccal distances between the abutment/fixture junction (AF) and the most coronal level of osseointegration (B) were 1.6 ± 0.6 and 2.4 ± 0.4 mm; between AF and the top of the bony crest (C), they were 1.4 ± 0.4 and 2.2 ± 0.2 mm at the test and control sites, respectively. The top of the peri-implant mucosa (PM) was located more coronally at the test (1.2 ± 0.6 mm) compared to the control sites (0.6 ± 0.5 mm). However, when the original position of the bony crest was taken into account, a higher bone loss and a more apical position of the peri-implant mucosa resulted at the test sites. CONCLUSIONS: The placement of implants into a sub-crestal location resulted in a higher vertical buccal bone resorption and a more apical position of the peri-implant mucosa in relation to the level of the bony crest at implant installation. Moreover, peri-implant hard-tissue dimensions were similar at sites prepared with either drills or Sonosurgery(®).

Alveolar Buccal Bone Overbuilding Before Tooth Extraction: A Preclinical Study.

BACKGROUND: After tooth extraction, a physiological shrinkage of the alveolar ridge occurs. Applying a buccal overbuilding some months before tooth extraction may create a stiffer hard tissue that might protect the alveolar crest from resorption. Hence, the aim of this experiment was to evaluate the dimensional changes in the alveolar crest after buccal overbuilding performed before tooth extraction. MATERIALS AND METHODS: At the test sites, an alveolar crest overbuilding was performed on the buccal aspect of the distal root of the third premolar using xenograft covered with a collagen membrane. No treatment was applied at the control sites. After 3 months, the distal roots of both third premolars were extracted and implants were immediately installed into the alveolus allowing a non-submerged healing. After 3 months, biopsies were collected. RESULTS: At the histological analyses, no statistically significant differences in hard tissue dimensions were found. The buccal bone plate at the test sites presented a tendency of higher resorption compared to the control sites. However, if the contribution of the residues of biomaterial was considered, a higher volumetric gain was registered at the test than at the control sites. CONCLUSIONS: The buccal overbuilding performed before tooth extraction did not contribute to the preservation of the alveolar crest dimensions after extraction. This could be due to failure to incorporate the graft into the newly formed bone.

Healing outcomes at implants installed in sites augmented with particulate autologous bone and xenografts. An experimental study in dogs.

AIM: To evaluate the integration of implants installed at the interface of pristine and grafted tissue augmented with particulate autologous bone or deproteinized bovine bone mineral (DBBM), concomitantly with a collagen membrane. MATERIAL AND METHODS: In 6 Labrador dogs, the distal root of (3)P(3) and (4)P(4) was endodontically treated and hemi-sected, and the mesial roots extracted concomitantly with the extraction of (2)P(2). The buccal bony walls were removed, and two box-shaped defects, one larger and one smaller, were created. After 3 months, flaps were elevated, and the defects were filled with particulate autologous bone or DBBM in the right and left side of the mandible, respectively. Collagen membranes were used to cover the grafted areas. Three months later, flaps were elevated, and a customized device was used as surgical guide to prepare the recipient sites at the interface between grafts and pristine bone. One implant was installed in each of the four defects. After 3 months, biopsies were harvested and ground sections prepared for histological evaluation. RESULTS: The augmentation technique was effective at all sites and all the foreseen implants were installed. In the histological analysis, all implants were integrated in mature bone, at both the buccal and lingual aspects. The most coronal bone-to-implant contact and the top of the buccal bony crest were located at a similar distance between test and control implants. However, these distances were higher at the larger compared with the smaller defects. Especially in the large defect, residual particles of DBBM were found embedded into connective tissue and located outside the bony crest. CONCLUSIONS: Particulate autologous bone as well as DBBM particles used to augment horizontally the alveolar bony process allowed for the osseointegration of implants installed after 3 months of healing.

Alveolar process preservation at implants installed immediately into extraction sockets using deproteinized bovine bone mineral - an experimental study in dogs.

AIM: To evaluate the soft tissue and the dimensional changes of the alveolar bony crest at sites where deproteinized bovine bone mineral (DBBM) particles, concomitantly with the placement of a collagen membrane, were used at implants installed into sockets immediately after tooth extraction. MATERIAL AND METHODS: The pulp tissue of the mesial roots of (3) P(3) was removed in six Labrador dogs, and the root canals were filled. Flaps were elevated bilaterally, the premolars hemi-sectioned, and the distal roots removed. Recipient sites were prepared in the distal alveolus, and implants were placed. At the test sites, DBBM particles were placed in the residual marginal defects concomitantly with the placement of a collagen membrane. No treatment augmentation was performed at the control sites. A non-submerged healing was allowed. Impressions were obtained at baseline and at the time of sacrifice performed 4 months after surgery. The cast models obtained were analyzed using an optical system to evaluate dimensional variations. Block sections of the implant sites were obtained for histological processing and soft tissue assessments. RESULTS: After 4 months of healing, no differences in soft tissue dimensions were found between the test and control sites based on the histological assessments. The location of the soft tissue at the buccal aspect was, however, more coronal at the test compared with the control sites (1.8 ± 0.8 and 0.9 ± 0.8 mm, respectively). At the three-dimensional evaluation, the margin of the soft tissues at the buccal aspect appeared to be located more apically and lingually. The vertical dislocation was 1 ± 0.6 and 2.7 ± 0.5 mm at the test and control sites, respectively. The area of the buccal shrinkage of the alveolar crest was significantly smaller at the test sites (5.9 ± 2.4 mm(2) ) compared with the control sites (11.5 ± 1.7 mm(2) ). CONCLUSION: The use of DBBM particles concomitantly with the application of a collagen membrane used at implants placed into sockets immediately after tooth extraction contributed to the preservation of the alveolar process.

Occlusal Splints and Exercise Performance: A Systematic Review of Current Evidence.

The role of the dento-mandibular apparatus and, in particular, occlusion and jaw position, received increased attention during last years. In the present study, we aimed to systematically review, on the light of the new potential insights, the published literature covering the occlusal splint (OS) applications, and its impact on exercise performance. A structured search was carried out including MEDLINE®/PubMed and Scopus databases with additional integration from external sources, between March and June 2021. To meet the inclusion criteria, studies published in the English language, involving humans in vivo, published from 2000 to 2021 and that investigated the role of occlusal splints on athletes' performance were selected. Starting from the 587 identified records, 17 items were finally included for the review. Four main aspects were considered and analyzed: (1) occlusal splint characteristics and occlusion experimental conditions, (2) jump performance, (3) maximal and explosive strength, and (4) exercise technique and biomechanics. The results of the systematic literature analysis depicted a wide heterogenicity in the experimental conditions and suggested the application of the OS as a way to improve athletes' or individuals' oral health, and as a potential tool to optimize marginal aspects of exercise performance.

Performance, balance and posture variations with Occlusal Splint and Taopatch® devices: a retrospettive cross-over study.

BACKGROUND: The aim of the study was to evaluate how muscular performances, balance and posture were influenced applying Occlusal Splints and Taopatch® 8 (Tao Technologies Srls, Cittadella, Padua, Italy) devices in athletes. METHODS: Eighteen athletes, 7 females and 11 males, with an average age of 23.8 years, were included. Two devices were used: 1) a customized soft occlusal splint to be applied to the lower ach; 2) nanotechnological devices based on carbon nanotubules and quantum dots (Taopatch®) positioned on C7 and xiphoid process. Four functional tests were performed: surface electromyography (sEMG), kinesiography, the squat jump and counter movement jump and handgrip test. The tests were performed in the following order: at the baseline (no treatments), and after having applied the bite alone, the occlusal splint and Taopatch® devices together and the Taopatch® devices alone. RESULTS: The sEMG showed an increased maximum clenching voltage in respect of the baseline for all treatments that included the occlusal splint. The kinesiography showed an improvement of the movements of the occlusal muscles. The squat jump increased the height of 10-14 mm, the best results registered with the bite. The handgrip showed an increased strength, that was higher with the bite and the Taopatch® devices used alone (~5 lbs.). CONCLUSIONS: The use of an occlusal splint and Taopatch® devices use alone or in conjunction immediately influenced strength and balance of the occlusal postural muscles.

Effects of Induced Malocclusion on Vertebral Alignment in Rats: A Controlled Study by CBCTs.

This study aimed to evaluate with CBCTs the alteration of vertebral alignment over time of induced malocclusion in rats. Crown pads increasing the vertical dimension of 0.5 mm were applied on the upper molars at one randomly selected side of the maxilla in rats (premature contact side) while the opposite side was left untreated (control side). Four groups were organized, ten animals each. In groups A, B, and C, the crowns were applied at time 0 (t-0). In group A, the crowns were removed after 2 weeks (t-2w) and euthanized after two more weeks, while in groups B and C, the animals were euthanized after 2 and 4 weeks (t-4w), respectively. No premature contacts were applied in group D. CBCTs were taken at t-0 in all animals before applying the crowns, at t-2w in group A before removing the crowns, and in all groups before the euthanasia. The changes in the iliac crest angle (ICA) that formed between the superior external margin of the iliac crest and the vertebral spine were evaluated. In groups A and B, after 2 weeks, the changes in ICA were statistically significant at p = 0.028 and p = 0.042, respectively. In group C, and in the control group D, the changes of ICA were not statistically significant (p = 0.058 and p = 0.414, respectively). In conclusion, the incease in monolateral occlusion in the molar region yielded a rotation of the lumbo-sacral segment towards the same side of the occlusal bite-raising.

Peri-implantitis at implants with different diameters: a pilot study in dogs.

AIM: To evaluate the progression of an induced peri-implantitis at implants with different diameters and the outcome of a corrective surgical debridement. METHODS: Three months after the extraction of the mandibular premolars and first molars in six dogs, non-submerged narrow implants (3.3 mm in diameter) or standard implants (3.8 mm and 4.1 mm) were installed in the molar regions, bilaterally. After 3 months, peri-implantitis lesions were induced with ligatures and plaque accumulation for 3 months. Plaque accumulation was allowed for a further month after ligatures removal. A surgical mechanical decontamination of the surfaces was subsequently performed using gauzes soaked in saline and irrigation. Five months after, biopsies were retrieved and histological slides prepared. X-rays were taken at treatment and 5 months after. RESULTS: Fourth months after peri-implantitis induction, 2.2 ± 1.0 mm at the standard implants and 3.2 ± 0.4 mm at the narrow implants were observed. Five months after treatment, a mean gain of marginal bone of 0.5 ± 0.6 mm was obtained at the standard implants and of 0.9 ± 0.4 at the narrow implants (p = 0.249). The vertical and horizontal defects were found partially closed. At the histological analysis, the coronal level of osseointegration after 5 months of healing was at 2.1 ± 0.8 mm at the standard implants, and 2.8 ± 0.3 mm at narrow implants (p = 0.116). CONCLUSIONS: In conclusion, the narrow implants showed a tendency of a faster progression of the induced peri-implantitis compared to standard implants. The implant diameter did not influence the outcome of a surgical treatment of an induced peri-implantitis.