Which region of the median palate is a suitable location of temporary orthodontic anchorage devices? A histomorphometric study on human cadavers aged 15–20 years

Introduction: Endosseus implants can provide a reliable anchorage during orthodontic treatment. The midpalatal structures around the sutura palatina mediana (SPM) are of special interest due to increasing placement of orthodontic implants in this area. Knowledge about the osseous conditions at this site is necessary to predict the expected degree of implant osseointegration.
Methods: The upper jaws of 10 human cadavers, aged 15–20 years, were decalcified, and cross-sectional specimens were obtained from four anterior-to-posterior palatal regions for histomorphometric analysis. The analyses focused on the amount of bone and the width of the SPM to determine the anatomical requirements for reliable insertion of palatal implants.
Results: Bone density [bone-volume (BV)/ tissue-volume (TV)] in all measured areas was 40–60%. The maximum density was measured at the level of the first premolars (54.9±5.9%) and the least values (44.2±9.6%) were measured at the level of the interconnecting line of the canines. The mean width of the SPM varies from 1.2 to 0.3 mm in different sections of the palate. In the median sagittal plane, the mean values of bone height to nasal cavity reached >5 mm as far as the level distal of the second premolars. Bone height 2 mm paramedian to the SPM decreased consistently from anterior (4.3±0.9 mm) to posterior (2.5±0.8 mm).
Conclusions: Our results indicate that the amount and quality of bone along the anterior palatal midline in 15-to-20-year olds is sufficient for orthodontic implantation. Even implantation posterior to the recommended first premolar level, at which orthodontic implants are most often placed, may be suitable. There are some limitations, however, due to small number of samples and variations of anatomical structures.     

Which device is more accurate to determine the stability/mobility of dental implants? A human cadaver study

Summary Non‐invasive devices including resonance frequency (RF) analysis and mobility measuring (MM) damping capacity assessment are used to measure implant stability/mobility. The aims of the study were to compare the primary stability of implant inserted into extraction sockets by using RF with cable, RF wireless and new wireless MM device, to clarify the relation between these devices and to understand the correlations between peri‐implant bone levels and implant stability. A total of 30 screw‐type implants (3·75 × 11 and 4·2 × 11 mm) were inserted into extraction sockets of eight mandibular pre‐molar regions of human cadavers. The primary stability of implants was measured by three devices after insertion. Peri‐implant vertical defects were created in millimetre increments ranging between 0 and 5 mm, and stability/mobility of implants were analysed. At placement, the mean implant stability quotient of RF with cable, RF wireless and MM device values was 46 ± 1, 57·8 ± 9 and ?5·4 ± 1, respectively. Statistical correlations were demonstrated between these devices (P = 0·001). Statistically significant differences were presented for all peri‐implant detects ranging between 0 and 5 mm for RF with cable and RF wireless at all increments. However, only a significant decrease was found between 0 and 1 mm defects, and 4 and 5 mm defects in MM device. Although RF with cable and RF wireless seem to be suitable to detect peri‐implant bone loss around implants in 1 mm increments, the new MM device may not be suitable to detect the 1 mm peri‐implant bone changes in human dried cadaver mandibles.     

How up-to-date are metal-based resin-bonded fixed partial dentures in the era of full-ceramics and dental implants? A case report

Regardless of the success of preventive measures the replace?ment of missing teeth in young patients with caries-free dentitions is a daily challenge for the clinician. The decision-making process concerning the different treatment options is difficult, based on several equivalent solutions. Thereby the significance of minimal invasive approaches is steadily increasing. In indicated cases, resin-bonded fixed partial dentures which were introduced in the last century still represent a well documented and minimally invasive procedure, even in the era of dental implants. In this article, clinical aspects of a conventional, metal-based resin-bonded fixed partial dentures are discussed according to the current literature and the clinical steps are presented in a clinical case.     

To splint or not to splint oral implants in the implant‐supported overdenture therapy? A systematic literature review

The objective of this systematic review was to assess the influence of splinted and unsplinted oral implants in the mandibular and maxillary implant-supported overdenture therapy, concerning the implant survival, the peri-implant parameters, the prosthetic complications and the patient satisfaction. An electronic MEDLINE search complemented by manual searching was conducted to identify randomized clinical trials, prospective and retrospective cohort studies on implant-supported overdentures with a mean follow-up of at least 3 years. Twelve studies from an initial yield of 1022 titles were finally selected and data were extracted. After an observation period of more than 3 years, there was no difference in implant survival rates between splinted and unsplinted design. From most of the investigations included in this study, it was mentioned that the unsplinted design needs more prosthetic maintenance. In more of the studies that were dealing with the satisfaction of the patients wearing implant-supported overdentures, no significant difference in the preference of the patients was reported. No significant difference in the peri-implant outcome between splinted and unsplinted design was found. Within the limits of this systematic review, it is concluded that there was no significant difference between the two different designs of implant-supported overdentures with respect to the soft tissue health status or patient satisfaction, although the bar-supported overdentures have been shown to need less prosthetic maintenance.     

Early or delayed palatoplasty in complete unilateral cleft lip and palate patients? A systematic review of the effects on maxillary growth

The aim of this study was to review the effects of early and late hard palate repair on maxillary growth. PubMed, Scopus, Web of Science, LILACS, Cochrane Library CENTRAL databases, OpenGrey, Google Scholar, and Clinical Trials were searched using a PICO strategy, with terms related to unilateral cleft lip and palate (UCLP) and timing of repair. Methodological quality evaluation was carried out using the Fowkes and Fulton guidelines, and quality (or certainty) of evidence and strength of recommendations were evaluated using GRADE (grading of recommendations, assessment, development and evaluation). Five retrospective and non-randomized studies were included in the study. Folkes and Fulton assessment showed a high risk of bias in all articles and very low levels of certainty (GRADE). The results showed conflicting findings for comparisons of the effects of timing of repair of hard palate in UCLP. Two studies presented better maxillary growth in a group operated on later (18 months after birth), two presented no differences between the results, and another presented better results in the group operated on earlier than 18 months of age. At this point, it cannot be proven or refuted that postponing hard palate surgery brings benefits for maxillary growth. Studies included in this review did not show similar conclusions. Randomized clinical trials present some ethical issues that make them difficult to perform.     

A systematic review and meta‐analysis of 3‐unit fixed dental prostheses: Are the results of 2 abutment implants comparable to the results of 2 abutment teeth?

The purpose of the systematic review and meta‐analysis was to compare the performance of 3‐unit bridges on teeth with 3‐unit bridges on implants, evaluating survival of the bridges, survival of the teeth or implants, condition of the hard and soft tissues surrounding the supports, complications and patient‐reported outcome measures (PROM) after a mean observation period of at least 1 year. A literature search was conducted using a combination of the search terms: fixed partial denture and fixed dental prostheses (FDPs). An electronic search for data published until January 2017 was undertaken using the MEDLINE, EMBASE and Cochrane Library databases. Eligibility criteria included clinical human studies, either randomised or not, interventional or observational, which evaluated the results of 3‐unit FDPs on either 2 implants or 2 abutment teeth. The search identified 1686 unique references. After applying eligibility criteria, 66 articles were included in the analysis. A total of 1973 3‐unit FDPs were supported by teeth, and 765 were implant‐supported. No significant differences were found either in the survival of the supporting abutments (P = .52; 99% vs 98.7% survival per year) or in the survival of the prostheses (P = .34; 96.4% vs 97.4% survival per year). Both treatments show an almost equally low complication rate, but there is a low level of reporting of hard and soft tissue conditions and PROM. It is concluded that implant‐supported 3‐unit FDPs seem to be a reliable treatment with survival rates not significantly different from the results of teeth‐supported 3‐unit FDPs.     

Do interleukin‐1 polymorphisms predict the development of jreiodontitis or the success of dental implants?

Factors which increase the risk of severe adult periodontitis (AP) may also contribute to the success of dental implants. To determine which cytokines may be relevant, levels of interleukin-1alpha (IL-1alpha), interleukin-1beta (IL-1beta), interleukin-1 receptor antagonist (IL-1ra), interleukin-6 (IL-6) and interferon-gamma (IFN-gamma) mRNA were quantitated in gingival tissue from periodontitis patients and healthy controls. Periodontitis significantly increased levels of IL-1alpha, IL-1beta, IL-6 and IFN-gamma mRNA relative to healthy tissues. IL-1 was selected for further study, as it has inflammatory and bone resorbing properties. We examined IL-1A(-889) and IL-1B(+3953) alleles in Caucasian patients with AP and early-onset periodontitis (EOP), patients with dental implants and healthy individuals. The IL-1B(+3953) polymorphism was associated with AP. This was evident from an increased homozygosity for allele 2 in patients with AP and a decreased heterozygosity in advanced AP patients. IL-1A(-889) and a composite genotype [IL-1A(-889)2 plus IL-1B(+3953)2] showed no association with the incidence of periodontitis, disease onset or disease severity. IL-1A(-889), IL-1B(+3953) and the composite genotype also showed no association with failure of dental implants.     

What is the relapse after Le Fort I maxillary advancement in cleft lip and palate patients? A systematic review

Oral and Maxillofacial Surgery - Le Fort I osteotomy is the most common procedure for maxillary advancement in cleft patients, and a significant relapse is expected in the postoperative period....     

Is the osseointegration of immediately and delayed loaded implants the same?—comparison of the implant stability during a 3‐month healing period in a prospective study

Objectives: The objectives of the present study were (1) to compare the stability of delayed loaded (DL) and immediately loaded (IL) ITI SLA implants during the first 3 months of the healing period using resonance frequency analysis (RFA) and (2) to determine the factors that affect implant stability during the healing period.
Materials and methods: To compare implant stability, RFA was performed on two groups of patients (12 patients received 25 IL implants and 47 patients received 79 DL implants) with a total 104 ITI SLA implants. Implant stability was measured directly by RFA at implant placement and consecutively once a week for 12 weeks. Statistical analyses were carried out to study implant stability differences between IL and DL groups.
Results: One of the 25 implants in the IL group failed, and no implant was lost in the DL group. Implant stability between the IL and DL groups showed a statistically significant difference ( P <0.05). The mean implant stability quotient of all measured implants from implant insertion to 12 weeks was 72.88 ± 5.39 for the DL and 75.86 ± 3.60 for the IL types. The lowest stability was at 4 weeks for DL implants (mean: 71.58 ± 5.11) and 2 weeks for IL implants (mean: 71.33 ± 2.97). In both groups, bone types I and II showed higher implant stability than bone type III ( P <0.05).
Conclusions: The findings of this study indicate that differences in osseointegration between IL and DL implants may be predicted according to differential implant stability.     

Analysis of blood supply in the hard palate and maxillary tuberosity—clinical implications for flap design and soft tissue graft harvesting (a human cadaver study)

Clinical Oral Investigations - The aim of the present study is to provide a detailed macroscopic mapping of the palatal and tuberal blood supply applying anatomical methods and studying specific...     

A comparative study of the bone contact to zirconium and titanium implants after 8 weeks of implantation in rabbit femoral condyles

Zirconium (Zr) has been found to have comparable characteristics to titanium with a favorable modulus of elasticity. In addition, the release of Zr-ions of a Zr implant is supposed to further increase the bone-to-implant response. Therefore, the objective of this study is to compare the bone contact to Zr and Ti implants in the femoral trabecular bone of rabbits. In addition, implants provided with a hydroxyapatite (HA) coating were included, as such a coating was proven before to enhance the secondary implant stability. A total of 32 implants consisting of 16 Zr (8 HA coated) and 16 Ti (8 HA coated) implants were installed in the femoral condyle of 16 rabbits. After 8 weeks of healing the femoral condyles including the implants were retrieved and studied histologically. The bone-to-implant contact (BIC) percentage was assessed and analyzed statistically. The BIC values of the uncoated Zr and Ti implants showed comparable BIC values (45.1 ± 14.8 vs. 45.5 ± 13.1). The BIC percentage was slightly higher for HA coated Zr and Ti implants (60.3 ± 17.1, 59.8 ± 16.4, respectively) compared to uncoated, but statistical testing indicated that this difference was not significant. It can be concluded that Zr and Ti implants show a comparable bone-implant contact after 8 weeks of implantation in the currently used rabbit model. In addition, the deposition of a sputtered HA coating on both Zr and Ti implants did not further improve their bone integration.     

Brånemark system implants in the posterior maxilla: clinical study of 660 implants followed for 5 to 12 years

Originally, osseointegrated implants were used principally in the anterior region of the mandible and maxilla, but use in the posterior segments of both arches is common today. The long-term success of implants placed in the posterior region, an environment of stronger forces and poorer bone quality, has not been thoroughly reviewed. The purpose of the present study was to review a large series of Br?nemark System implants placed in posterior maxillae (660 implants in 202 patients) that have been restored with fixed partial ceramometal restorations and followed for as long as 12 years after loading. Thirteen of the implants (2%) failed between placement and loading, 12 implants were lost between loading and the end of the first year, and 10 failed thereafter, 2 as the result of fractures at 3 and 4 years. The cumulative success rate is therefore 94.4% at 5 to 6 years and 93.4% after 10 years. The quality and quantity of bone appeared to have little influence on the success rate. Surgical techniques are particularly important to the success of osseointegrated implants placed in the posterior maxilla. With careful surgical planning and execution, a success rate of approximately 95% at 5 years can be achieved.     

Is insertion torque correlated to bone–implant contact percentage in the early healing period? A histological and histomorphometrical evaluation of 17 human‐retrieved dental implants

Objective: A precise and scientifically established method for the evaluation of the bone quality/primary stability is the measure of the insertion torque (IT). The aim of this study was a comparison between the IT values and the bone–implant contact percentage (BIC) of human implants retrieved after a 4/8-week healing period.
Materials: Seventeen implants, all with a sandblasted and acid-etched surface, were evaluated in the present study.
Methods: The implants had been retrieved for different causes, after 4/8 weeks, with a 5 mm trephine bur, and immersed in 10% buffered formalin to be processed for histology.
Results: A not statistically significant correlation was found between IT and BIC ( P ≤0.892).
Conclusions: In the present study on human-retrieved implants, no statistically significant correlation was found between the IT values and BIC. These results could be due to a lack of relationship between bone structure and IT, or to the fact that primary stability may not only be influenced by bone volumetrical density and/or bone trabecular connectivity but also by the thickness and density of the cortical layer. Moreover, the present knowledge of the bone microstructure is not enough to explain the relationship of bone quality and primary implant stability.     

Preferences of dental care providers in maintaining compromised teeth in relation to their professional status: implants instead of periodontally involved maxillary molars?

Aim: The purpose of this study was to evaluate the dentists' decision making in the maxillary molar region to find out how it is influenced by general practitioners' and specialists' characteristics as well as by the external evidence. Material and methods: A questionnaire was developed containing clinical cases and statements to assess practitioners' opinions on the treatment of periodontally involved maxillary molars and implant therapy with sinus grafting. Data were analysed with respect to the dentists' age and speciality. Results: Three hundred and forty questionnaires were evaluated (24% from universities, 76% from educational courses, overall response rate 35.1%). Forty six per cent of all participants indicated they had specialised, 52% placed dental implants, while 33% performed sinus grafting and 64% periodontal surgeries. Forty six per cent were against or were indecisive about having sinus grafting performed on themselves. The treatment proposals given for the clinical cases revealed a preference among older dentists and general practitioners for regenerative treatments even when these were not evidence based in through‐and‐through furcation involvements. Resective therapies were most often selected by periodontists. Prosthodontists tended to prefer more invasive treatment options with extractions and augmentations. More experienced general practitioners favoured conventional fixed dental prostheses in free‐end situations or no treatment rather than the complicated augmentation procedures, which were preferred by younger dentists. Conclusions: Implant placement seems to be widely accepted by almost all subjects, who may either place implants themselves or refer patients. More information seems to be needed on the indications for regenerative therapies for furcation involved maxillary molars, and guidelines required for decision making in complex clinical situations. To cite this article:
Zitzmann NU, Scherrer SS, Weiger R, Lang NP, Walter C. Preferences of dental care providers in maintaining compromised teeth in relation to their professional status: implants instead of periodontally involved maxillary molars?.
Clin. Oral Impl. Res. 22 , 2011; 143–150.
doi: 10.1111/j.1600‐0501.2010.02062.x