Group 2 ITI Consensus Report: Technological developments in implant prosthetics.

OBJECTIVES: Group-2 reviewed the scientific evidence in the field of «Technology¼. Focused research questions were: (1) additive versus subtractive manufacturing of implant restorations; (2) survival, complications, and esthetics comparing prefabricated versus customized abutments; and (3) survival of posterior implant-supported multi-unit fixed dental prostheses. MATERIALS AND METHODS: Literature was systematically screened, and 67 publications could be critically reviewed following PRISMA guidelines, resulting in three systematic reviews. Consensus statements were presented to the plenary where after modification, those were accepted. RESULTS: Additively fabricated implant restorations of zirconia and polymers were investigated for marginal/internal adaptation and mechanical properties without clear results in favor of one technology or material. Titanium base abutments for screw-retained implant single crowns compared to customized abutments did not show significant differences concerning 1-year survival. PFM, veneered and monolithic zirconia implant-supported multi-unit posterior fixed dental prostheses demonstrated similar high 3-year survival rates, whereas veneered restorations exhibited the highest annual ceramic fracture and chipping rates. CONCLUSIONS: For interim tooth-colored implant single crowns both additive and subtractive manufacturing are viable techniques. The clinical performance of additively produced restorations remains to be investigated. Implant single crowns on titanium base abutments show similar clinical performance compared to other type of abutments; however, long-term clinical data from RCTs are needed. The abutment selection should be considered already during the planning phase. Digital planning facilitates 3D visualization of the prosthetic design including abutment selection. In the posterior area, monolithic zirconia is recommended as the material of choice for multi-unit implant restorations to reduce technical complications.

Early loading of sandblasted and acid-etched (SLA) implants: a prospective split-mouth comparative study.

Sandblasted and acid-etched (SLA) implants were recently introduced to reduce the healing period between surgery and prosthesis. In this split-mouth study, SLA implants were compared to titanium plasma-sprayed (TPS) implants under loaded conditions one year after placement in 32 healthy patients, with comparable bilateral edentulous sites and no discrepancies in the opposing dentition. The surgical procedure was performed by the same operator and was identical at 68 SLA (test) and 68 TPS (control) sites. Tapping was never performed and primary stability was always achieved. Abutment connection was carried out at 35 Ncm 6 weeks postsurgery for test sites and 12 weeks for the controls, by the same dentist blind to the type of surface of the implant. In 4 of the 68 test sites the implant rotated slightly, patients reported minor pain and connection was not completed. Provisional restoration was fabricated and a new tightening was performed after six weeks. Similar gold-ceramic restorations were cemented on the same type of solid abutments on both sites. No implant was lost. Clinical measures and radiographic changes were recorded by the same operator, blind to the type of surface of the implant, 1 year post surgery. No significant differences were found with respect to presence of plaque (24% vs. 27%), bleeding on probing (24% vs. 31%), mean pocket depth (3.3 mm vs. 2.9 mm) or mean marginal bone loss (0.65 mm vs. 0.77 mm). The results suggest that SLA implants are suitable for early loading at 6 weeks. Limited implant spinning may occasionally be found but, if properly handled, it produces no detrimental effect on the clinical outcome.

Coronally advanced flap for the treatment of buccal gingival recessions with and without enamel matrix derivative. A split-mouth study.

BACKGROUND: The coronally advanced flap (CAF) is a predictable method for achieving root coverage in buccal gingival recessions. The use of enamel matrix derivative (EMD) has already been tested in treating intrabony defects. No clinical comparative study has been published evaluating the CAF in combination with EMD in treating buccal gingival recessions. METHODS: This split-mouth study was performed to assess the efficacy of EMD to improve the results of a root coverage procedure. Fourteen pairs of Miller Class I and II bilateral comparable defects were selected in 12 patients. In each patient, one site was randomly assigned to the test group and the contralateral site to the control group. The treatment consisted of a CAF procedure with (test) or without (control) EMD. Gingival recession (REC), clinical attachment level (CAL), probing depth (PD), and extension of keratinized tissue (KT) were recorded at baseline and 6 months postsurgery. RESULTS: The average initial REC was 3.71 mm (SD +/- 1.68) for the test group, and 3.50 mm (SD +/- 1.56) for the control group. The 2 groups were statistically homogeneous. The mean root coverage was 3.36 mm (SD +/- 1.55), corresponding to a value of 91.2% for the test group, and 2.71 mm (SD +/- 1.20), equal to 80.9% for the control group. The differences between the 2 groups were not statistically significant. The mean CAL gain was 3.57 mm (SD +/- 1.55) for the test group and 2.79 mm (SD +/- 1.19) for the control group. No changes of PD and KT were found. CONCLUSIONS: This study suggests that EMD does not seem to significantly improve the clinical outcomes of gingival recession treated by means of CAF, even though the test group showed slightly better results in terms of root coverage and CAL. Further studies with a larger number of teeth and higher statistical power are needed to support this conclusion.

Treatment of buccal gingival recessions with e-PTFE membranes and miniscrews: surgical procedure and results of 12 cases.

A surgical technique to achieve root coverage in buccal gingival recessions by means of expanded polytetrafluoroethylene membranes in combination with miniscrews is presented. After raising a trapezoidal split flap, supporting screws were used to create a large space underneath the membrane, while head screws were employed for perfect stabilization of the Teflon barrier. Intramarrow perforations were made to induce the rapid formation of a large blood clot with abundant availability of progenitor cells. The membrane and the miniscrews were removed after 3 or 4 weeks. The treatment of 12 cases, with mucogingival defects 4 to 7 mm deep, resulted in a mean root coverage of 84%.

[Absorbed doses in dental radiology]. / Dosi assorbite nella radiologia dentale.

The growing use of dento-maxillo-facial radiographic examinations has been accompanied by the publication of a large number of studies on dosimetry. A thorough review of the literature is presented in this article. Most studies were carried out on tissue equivalent skull phantoms, while only a few were in vivo. The aim of the present study was to evaluate in vivo absorbed doses during Orthopantomography (OPT). Full Mouth Periapical Examination (FMPE) and Intraoral Tube Panoramic Radiography (ITPR). Measurements were made on 30 patients, reproducing clinical conditions, in 46 anatomical sites, with 24 intra- and 22 extra-oral thermoluminiscent dosimeters (TLDS). The highest doses were measured, in orthopantomography, at the right mandibular angle (1899 mu Gy) in FMPE on the right naso-labial fold (5640 mu Gy and in ITPR on the palatal surface of the left second upper molar (1936 mu Gy). Intraoral doses ranged from 21 mu Gy, in orthopantomography, to 4494 mu Gy in FMPE. Standard errors ranged from 142% in ITPR to 5% in orthopantomography. The highest rate of standard errors was found in FMPE and ITPR. The data collected in this trial are in agreement with others in major literature reports. Disagreements are probably due to different exam acquisition and data collections. Such differences, presented comparison in several sites, justify lower doses in FMPE and ITPR. Advantages and disadvantages of in vivo dosimetry of the maxillary region are discussed, the former being a close resemblance to clinical conditions of examination and the latter the impossibility of collecting values in depth of tissues. Finally, both ITPR and FMPE required lower doses than expected, and can be therefore reconsidered relative to their radiation risk.

Comparative study of a bioresorbable and a non-resorbable membrane in the treatment of human buccal gingival recessions.

Twelve patients with bilateral comparable gingival recessions were treated using a split mouth design, to compare the relative success of root coverage by two regenerative procedures. The areas of recession treated were Class I or II according to Miller's classification and caused either an esthetic problem and/or root sensitivity. The symmetrical defects, on the maxillary canines, 4 mm or deeper, were randomly assigned in each patient to surgical procedures with either a bioresorbable matrix barrier (test) or a non-resorbable expanded polytetrafluoroethylene membrane (control). Gingival recession, clinical attachment level, probing depth, and extension of keratinized tissue were measured at baseline and at 6 months postsurgically. Both procedures resulted in significant root coverage (P < 0.0001) and attachment gain (P < 0.0001). The gingival recession decreased from 4.75 +/- 0.22 mm to 0.83 +/- 0.24 mm and from 4.75 +/- 0.22 mm to 0.75 +/- 0.22 mm, corresponding to a mean root coverage of 82.4% and 83.2%, at the test and control sites respectively. The average clinical attachment gain was 4.33 +/- 0.44 mm at the test sites compared to 4.42 +/- 0.48 mm for the non-resorbable barrier. No significant changes were found for probing depth and keratinized tissue. Data analysis did not demonstrate any significant difference between the two procedures for any of the variables included. However, a questionnaire given to each patient revealed the single-step surgery to be the patients' choice.

Radiological visibility of small artificial periapical bone lesions.

Previous studies have indicated that the visibility of periapical lesions on a radiograph is determined by erosion of either the cortex or the junction area between cortex and spongiosa. In the present study, artificial lesions, varying in diameter from 1.6 to 4.5 mm, were produced with a round dental bur at 32 sites in 27 blocks from four dried human mandibles embedded in paraffin and radiographed under standardized conditions. The radiographs were evaluated by three observers with differing degrees of radiological experience, and the results expressed as Mean Visibility Index (MVI) and Mean Difference Index (MDI). Six parameters were measured at each site, thickness of the bone, of the cortex and of the spongiosa, density of the spongiosa, cortex/spongiosa ratio, and erosion of the cortex, and their correlation with the two indices determined by stepwise and multiple regression. It was found that MVI was significantly associated not only with the erosion of the cortex but also the density of the spongiosa and the diameter of the lesion. MDI was found to be associated mainly with cortex erosion.

Primary impaction of primary teeth: a review and report of three cases.

Primary impaction of primary teeth is rare. Only ten cases have been found in the world literature. It affects almost always second molars and the finding is usually occasional. Three cases of this abnormality, two of the upper jaw and one of the mandible, are presented. The analysis of the characteristics of these cases and the cases in the literature, suggests that ankylosis has probably a leading role in the etiopathogenesis. The following criteria for a correct diagnosis is presented: 1) deep retention into the bone; 2) absence of caries, restorations and resorptions; 3) frequent passing of the corresponding permanent premolar; and possible retention of the corresponding adjacent tooth. More attention is recommended in the study of the lesion for the future.