Impact of crestal and subcrestal implant placement upon changes in marginal peri-implant bone level. A systematic review.

BACKGROUND: To systematically assess studies analyzing peri-implant bone loss in implants placed in crestal and subcrestal position. MATERIAL AND METHODS: Following the recommended methods for systematic reviews and meta-analyses (PRISMA), an electronic search was conducted in the PubMed (MEDLINE), EMBASE and LILACS databases to identify all relevant articles published up until April 2017. The search included human studies comparing marginal bone loss (MBL) between a control group and a study group with a minimum of 10 patients and a minimum follow-up of 6 months after prosthetic loading with rough neck implants. Two independent reviewers assessed the risk of bias in the selected studies based on the Newcastle-Ottawa scale for observational studies and the Cochrane Collaboration for clinical trials. RESULTS: Of 342 potentially eligible items, 7 complied with the inclusion criteria. One article was retrieved through the manual search. Eight articles were finally included: five experimental and three observational studies. The risk of bias assessed by the Cochrane Collaboration and Newcastle-Ottawa showed a high risk of bias. The mean follow-up period was 21 months (range 6-36 months). In four studies, implants placed in a crestal position presented higher MBL than subcrestal implants - the differences being significant in one study, while in three studies, implants placed in a subcrestal position presented greater MBL than crestal implants, with significant differences in only one study. CONCLUSION: Despite its limitations, the present systematic review did not find better outcomes between crestal and subcrestal implant placement, however, new studies will be needed, involving improved designs and the standardization of protocols to allow statistical comparisons and the drawing of firm conclusions.

Volumetric variation of peri-implant soft tissues in convergent collar implants and crowns using the biologically oriented preparation technique (BOPT).

BACKGROUND: To evaluate the changes in the peri-implant soft tissues of convergent collar implants with biologically oriented preparation technique (BOPT) crowns, 10 months after loading. MATERIAL AND METHODS: A pilot study was carried out from January 2016 to October 2017 involving 14 patients with one or two implants in the posterior mandibular sector. A total of 32 convergent collar implants were placed using a non-submerged protocol. Three months later the provisional cemented crowns were fitted using the BOPT approach with the finish line 1-1.5 mm below the gingival margin, simulating coronal emergence of a natural tooth. The soft tissue changes were measured with an intraoral scanner at two different timepoints: a) on the day of provisionalization, before prosthetic loading; and b) 10 months later without the provisional prosthesis. The STL files were superimposed and the soft tissue changes were recorded using a color scale with measurement of the volumetric changes in mm3. RESULTS: A mean increase in peri-implant mucosal volume of 64.7 mm3 was observed in 29 implants. The zones with the greatest increase in soft tissue volume were the papillae of implants with adjacent teeth and the peri-implant buccal margin. Three implants showed a mean decrease in soft tissue volume of -25.1 mm3. CONCLUSIONS: The fitting and design of crowns using the biologically oriented preparation technique (BOPT) over convergent collar implants affords a significant increase in peri-implant soft tissue volume both at the level of the papillae and in the buccal margin.

Simultaneous and delayed direct sinus lift versus conventional implants: Retrospective study with 5-years minimum follow-up.

BACKGROUND: To compare the radiological parameters and success of posterior maxillary direct sinus lift with simultaneous or delayed implant placement, or implant placement in native bone, after a minimum follow-up period of 5 years. MATERIAL AND METHODS: A retrospective cohort study was carried out in a university clinic, selecting patients subjected to implant treatment in the posterior maxilla between the years 2005 and 2011. The patients were divided into three groups: 1) implants placed in native bone; 2) direct sinus lift with simultaneous implant placement; and 3) direct sinus lift with delayed implant placement. Bone crest level, bone loss, vertical bone gain, and implant success and survival after a minimum follow-up period of 5 years after prosthetic loading were analyzed. RESULTS: A total of 163 patients and 329 implants were included in the study. The mean duration of follow-up was 7.0 ± 1.9 years. Bone loss and implant success and survival were very similar in all three groups, with no significant differences among them. Graft reabsorption was greatest during the first 12 months, though graft stabilization was confirmed after 5 years of follow-up. CONCLUSIONS: Bone loss and percentage success and survival proved very similar for the implants placed in native bone and for sinus lift with simultaneous or delayed implant placement. The height of the graft material decreased mainly in the first 12 months, and continued until stabilization after 5 years, with no significant variations thereafter.

Comparison of peri-implant bone loss between conventional drilling with irrigation versus low-speed drilling without irrigation.

BACKGROUND: To compare the technique of high speed drilling with irrigation and low speed drilling without irrigation in order to evaluate the success rate and peri-implant bone loss at 12 months of follow-up. MATERIAL AND METHODS: A randomized, controlled, parallel-group clinical trial was carried out in patients requiring dental implants to rehabilitate their unitary edentulism. Patients were recruited from the Oral Surgery Unit of the University of Valencia (Spain) between September 2014 and August 2015. Patients who met the inclusion criteria were randomized to two groups: group A (high-speed drilling with irrigation) and group B (low-speed drilling without irrigation). The success rate and peri-implant bone loss were recorded at 12 months of follow-up. RESULTS: Twenty-five patients (9 men and 16 women) with 30 implants were enrolled in the study: 15 implants in group A and 15 implants in group B. The mean bone loss of the implants in group A and group B was 0.83 ± 0.73 mm and 0.62 ± 0.70 mm, respectively (p> 0.05). In the maxilla, the bone loss was 1.04 ± 0.63 mm in group A and 0.71 ± 0.36 mm in group B (p> 0.05), while bone loss in the mandible was 0.59 ± 0.80 mm in group A and 0.69 ± 0.77 mm in group B (p> 0.05). The implant success rate at 12 months was 93.3% in group A and 100% in group B. CONCLUSIONS: Within the limitations of the study, the low-speed drilling technique presented peri-implant bone loss outcomes similar to those of the conventional drilling technique at 12 months of follow-up.

Influence of the prosthetic arm length (palatal position) of zygomatic implants upon patient satisfaction.

BACKGROUND: To assess the influence of the prosthetic arm length (palatal position) of zygomatic implants upon patient comfort and stability, speech, functionality and overall satisfaction. MATERIAL AND METHODS: A retrospective clinical study was made of patients subjected to rehabilitation of atrophic maxilla with complete maxillary implant-supported fixed prostheses involving a minimum of two zygomatic implants (one on each side) in conjunction with premaxillary implants, and with 12 months of follow-up after implant loading. Subjects used a VAS to score general satisfaction, comfort and stability, speech and functionality, and the results were analyzed in relation to the prosthetic arm length of the zygomatic implants 12 months after prosthetic delivery. RESULTS: Twenty-two patients participated in the study, receiving 22 prostheses anchored on 148 implants (44 were zygomatic and 94 were conventional implants). The mean right and left prosthetic arm length was 5.9±2.4 mm and 6.1±2.7 mm, respectively, with no statistically significant differences between them (p=0.576). The mean scores referred to comfort/retention, speech, functionality and overall satisfaction were high - no correlation being found between prosthetic arm length and patient satisfaction (p=0.815). CONCLUSIONS: No relationship could be identified between prosthetic arm length (palatal position) and patient satisfaction.

Soft tissue cell adhesion to titanium abutments after different cleaning procedures: preliminary results of a randomized clinical trial.

OBJECTIVES: A randomized controlled trial was performed to assess soft tissue cell adhesion to implant titanium abutments subjected to different cleaning procedures and test if plasma cleaning can enhance cell adhesion at an early healing time. STUDY DESIGN: Eighteen patients with osseointegrated and submerged implants were included. Before re-opening, 18 abutments were divided in 3 groups corresponding to different clinical conditions with different cleaning processes: no treatment (G1), laboratory customization and cleaning by steam (G2), cleaning by plasma of Argon (G3). Abutments were removed after 1 week and scanning electron microscopy was used to analyze cell adhesion to the abutment surface quantitatively (percentage of area occupied by cells) and qualitatively (aspect of adhered cells and presence of contaminants). RESULTS: Mean percentages of area occupied by cells were 17.6 ± 22.7%, 16.5 ± 12.9% and 46.3 ± 27.9% for G1, G2 and G3 respectively. Differences were statistically significant between G1 and G3 (p=0.030), close to significance between G2 and G3 (p=0.056), and non-significant between G1 and G2 (p=0.530). The proportion of samples presenting adhered cells was homogeneous among the 3 groups (p-valor = 1.000). In all cases cells presented a flattened aspect; in 2 cases cells were less efficiently adhered and in 1 case cells presented filipodia. Three cases showed contamination with cocobacteria. CONCLUSIONS: Within the limits of the present study, plasma of Argon may enhance cell adhesion to titanium abutments, even at the early stage of soft tissue healing. Further studies with greater samples are necessary to confirm these findings.

Influence of implant neck design and implant-abutment connection type on peri-implant health. Radiological study.

OBJECTIVE: To carry out a comparative study of two implants with different neck features and prostheses platform connection (machined with external connection and rough-surfaced with switching platform) upon peri-implant marginal bone loss, before and after functional loading. MATERIAL AND METHODS: A randomized, prospective radiological study was made. Eighteen totally edentulous patients were selected. Subjects were divided into two groups according to the type of implant neck used: (a) Osseous(®), with machined surface, without microthreads, external connection, and without platform switching; and (b) Inhex(®), with treated surface, microthreads, internal connection, and platform switching. Mesial and distal marginal bone loss was measured. Implant success was assessed according to the criteria of Buser. Control timepoints were as follows: (a) at implant placement; (b) at prosthesis placement; (c) 6 months after loading; (d) 12 months after loading. RESULTS: Fifteen patients that received 120 dental implants were included: 47% Osseous(®) group and 53% Inhex(®) group. Global mean marginal bone loss with Osseous(®) was 0.27 ± 0.43 mm and 0.38 ± 0.51 mm as determined 6 and 12 months after prosthetic loading, respectively, whereas in the case of Inhex(®) was 0.07 ± 0.13 and 0.12 ± 0.17 mm. These differences were statistically significant (P = 0.047). Difference between Osseous(®) and Inhex(®) in maxilla (P = 0.272) and mandibular (P = 0.462) bone loss were not statistically significant. CONCLUSIONS: Bone loss after 6 and 12 months proved statistically significant between two groups, with comparatively greater loss in the case of Osseous(®) implants vs. Inhex(®) implants. Regardless the heterogeneity of the two groups (neck shape, microthreads, surface texture), the implant-abutment connection appears to be a significant factor on peri-implant crestal bone levels. Anyway, in both groups, the values obtained were within normal ranges described in the literature.

Treatment of orofacial pain in patients with stylomandibular ligament syndrome (Ernest Syndrome).

INTRODUCTION: Ernest syndrome involves the stylomandibular ligament. It is characterised by pain in the preauricular area and mandibular angle, radiating to the neck, shoulder, and eye on the same side, and associated with pain during palpation of that ligament. The purpose of this study is to describe the clinical characteristics, treatment, and course of the disease in a series of patients with Ernest syndrome. METHODS: Retrospective observational study covering the period from 1998 to 2008. We recorded patients' age, sex, duration of the disorder, and pain characteristics. All patients were injected with 40mg triamcinolone acetonide at the mandibular insertion of the stylomandibular ligament. RESULTS: The study included a total of 6 patients. Mean age was 40.3 years (range, 35-51). All of the subjects were women. Four patients had undergone lengthy dental treatments in the month prior to onset of the pain. The mean time between pain onset and first consultation was 23 months. The syndrome resolved completely in all cases after treatment, with a minimum follow-up period of 12 months. CONCLUSIONS: We analysed the clinical characteristics, treatment, and course of disease in 6 patients with Ernest syndrome. Correct diagnosis is the key to being able to provide proper treatment. This disorder is sometimes confused with other types of orofacial pain, and may therefore be more prevalent than the literature would indicate.

Marginal bone loss in relation to platform switching implant insertion depth: An update.

A review is made, analyzing marginal bone loss in relation to the depth of implant insertion with platform switching, according to the position of the neck (supracrestal, crestal or subcrestal), and evaluating survival of the implants. A PubMed search was made of the studies in animals and humans published between 2005 and 2011, specifying platform insertion depth (supracrestal, crestal or subcrestal) and registering marginal bone loss from the time of prosthetic restoration to the end of follow-up (minimum 6 months). A total of 30 studies were included. The bone loss associated with implants placed at supracrestal level was slightly smaller than in the case of implants placed at subcrestal level, though statistical significance was not reached. The mean marginal bone loss values were 0.0 mm to 0.9±0.4 mm for the implants with the neck located at supracrestal level; 0.05 mm to 1.40±0.50 mm for those at subcrestal level; and 0.26±0.22 mm to 1.8±0.39 mm for those in a crestal location, after 6-60 months of follow-up. The survival rate was 88.6-100% for the implants with the neck positioned at crestal level, versus 98.3-100% below the crest, and 100% above the crest. The heterogeneity of the studies (surgical technique, platform surface texture, radiographic measurement techniques, etc.) made it difficult to establish a relationship between marginal bone loss and the supracrestal, crestal or subcrestal location of platform switching. Key words:Dental implants, platform switching, insertion depth, crestal insertion level, bone loss.

Comparative study between manual injection intraosseous anesthesia and conventional oral anesthesia.

OBJECTIVE: To compare intraosseous anesthesia (IA) with the conventional oral anesthesia techniques. MATERIAL AND METHOD: A simple-blind, prospective clinical study was carried out. Each patient underwent two anesthetic techniques: conventional (local infiltration and locoregional anesthetic block) and intraosseous, for respective dental operations. In order to allow comparison of IA versus conventional anesthesia, the two operations were similar and affected the same two teeth in opposite quadrants. RESULTS: A total of 200 oral anesthetic procedures were carried out in 100 patients. The mean patient age was 28.6±9.92 years. Fifty-five vestibular infiltrations and 45 mandibular blocks were performed. All patients were also subjected to IA. The type of intervention (conservative or endodontic) exerted no significant influence (p=0.58 and p=0.62, respectively). The latency period was 8.52±2.44 minutes for the conventional techniques and 0.89±0.73 minutes for IA - the difference being statistically significant (p<0.05). Regarding patient anesthesia sensation, the infiltrative techniques lasted a maximum of one hour, the inferior alveolar nerve blocks lasted between 1-3 hours, and IA lasted only 2.5 minutes - the differences being statistically significant (p≤0.0000, Φ=0.29). Anesthetic success was recorded in 89% of the conventional procedures and in 78% of the IA. Most patients preferred IA (61%)(p=0.0032). CONCLUSIONS: The two anesthetic procedures have been compared for latency, duration of anesthetic effect, anesthetic success rate and patient preference. Intraosseous anesthesia has been shown to be a technique to be taken into account when planning conservative and endodontic treatments.

A prospective clinical study of polycarboxylate cement in periapical surgery.

OBJECTIVE: To evaluate the clinical efficacy of polycarboxylate cement as retrograde filling material. DESIGN: A prospective clinical study was made of 25 patients subjected to periapical surgery with ultrasound and magnifying loupes, in which polycarboxylate cement was used as retrograde filling material. Measurements were made of the area and diameter of the lesions pre- and postoperatively, and 6 and 12 months after the operation. The apical resection and retrograde filling areas were also measured, and the prognosis following surgery was recorded. RESULTS: A total of 23 patients with 31 apicoectomized teeth were studied (2 patients being lost to follow-up). The mean area of the periapical lesions before surgery was 52.25 mm2, with a mean major diameter of 6.1 mm and a mean lesser diameter of 4.8 mm. The success rate after 12 months was 54.7%, according to the criteria of Von Arx and Kurt. The prognosis was poorer in females, in larger lesions, and in cases with larger retrograde filling areas. CONCLUSIONS: Polycarboxylate cement offers good results, with important bone regeneration after periapical surgery.