Virtual tissue alignment and cutting plane definition--a new method to obtain optimal longitudinal histological sections.

Histomorphometric evaluation of the buccal aspects of periodontal tissues in rodents requires reproducible alignment of maxillae and highly precise sections containing central sections of buccal roots; this is a cumbersome and technically sensitive process due to the small specimen size. The aim of the present report is to describe and analyze a method to transfer virtual sections of micro-computer tomographic (CT)-generated image stacks to the microtome for undecalcified histological processing and to describe the anatomy of the periodontium in rat molars. A total of 84 undecalcified sections of all buccal roots of seven untreated rats was analyzed. The accuracy of section coordinate transfer from virtual micro-CT slice to the histological slice, right-left side differences and the measurement error for linear and angular measurements on micro-CT and on histological micrographs were calculated using the Bland-Altman method, interclass correlation coefficient and the method of moments estimator. Also, manual alignment of the micro-CT-scanned rat maxilla was compared with multiplanar computer-reconstructed alignment. The supra alveolar rat anatomy is rather similar to human anatomy, whereas the alveolar bone is of compact type and the keratinized gingival epithelium bends apical to join the junctional epithelium. The high methodological standardization presented herein ensures retrieval of histological slices with excellent display of anatomical microstructures, in a reproducible manner, minimizes random errors, and thereby may contribute to the reduction of number of animals needed.

Temporary anchorage device usage: a survey among Swiss orthodontists.

BACKGROUND The aim of the survey was to obtain information on the treatment plan preferences, mechanics and characteristics of temporary anchorage device (TAD) application using a single case presented to orthodontists in Switzerland. METHODS A structured questionnaire to be completed by all study participants with case-specific (treatment plan including mechanics and TAD usage) and general questions (general fixed appliance and TAD usage as well as professional, educational and demographic questions) together with an orthodontic borderline case was utilised. The case was a female adult with dental Class II/2, deep bite and maxillary anterior crowing, who had been treated in childhood with extraction of four premolars and fixed appliance followed by wisdom tooth extraction. RESULTS The response rate was 24.4% (108 out of 443). The majority (96.3%, 104) proposed comprehensive treatment, while 3.7% (4) planned only alignment of maxillary teeth. 8.3% (9) included a surgical approach in their treatment plan. An additional 0.9% (1) combined the surgical approach with Class II mechanics. 75.1% (81) decided on distalization on the maxilla using TADs, 7.4% (8) planned various types of Class II appliances and 3.7% (4) combined distalization using TADs or headgear with Class II appliances and surgery. Palatal implants were the most popular choice (70.6%, 60), followed by mini-screws (22.4%, 19) and mini-plates on the infrazygomatic crests (7.0%, 6). The preferred site of TAD insertion showed more variation in sagittal than in transversal dimension, and the median size of mini-screws used was 10.0-mm long (interquartile range (IQR) 2.3 mm) and 2.0-mm wide (IQR 0.3 mm). CONCLUSIONS Distalization against palatal implants and then distalization against mini-screws were the most popular treatment plans. Preferred site for TAD insertion varied depending on type and size but varied more widely in the sagittal than in the transversal dimension.

Incidental findings on cone beam computed tomography scans in cleft lip and palate patients.

OBJECTIVES Cone beam computed tomography (CBCT) is frequently used in treatment planning for alveolar bone grafting (ABG) and orthognathic surgery in patients with cleft lip and palate (CLP). CBCT images may depict coincident findings. The aim of this study was to assess the prevalence of incidental findings on CBCT scans in CLP patients. SUBJECTS AND METHODS Initial CBCTs taken from consecutive patients (n = 187; mean age 11.7 years, range 6.9-45) with a non-syndromic orofacial cleft from January 2006 until June 2012 were systematically evaluated. Twenty-eight patients (mean age 19.3 years, range 13.2-30.9) had been subjected to ABG before their first CBCT was taken; 61 patients had a CBCT before and after ABG. Sinuses, nasopharynx, oropharynx, throat, skull, vertebrae, temporomandibular joint (TMJ), maxilla and mandible were checked for incidental findings. RESULTS On 95.1 % of the CBCTs, incidental findings were found. The most prevalent were airway/sinus findings (56.1 %), followed by dental problems, e.g. missing teeth (52 %), nasal septum deviation (34 %), middle ear and mastoid opacification, suggestive for otitis media (10 %) and (chronic) mastoiditis (9 %), abnormal TMJ anatomy (4.9 %) and abnormal vertebral anatomy (1.6 %). In the 28 patients whose first CBCT was taken at least 2 years after ABG, bone was still present in the reconstructed cleft area except in 2 out of 12 patients with a bilateral CLP. The ABG donor site (all bone grafts were taken from the chin area) was still recognizable in over 50 % of the patients. Based on the CBCT findings, 10 % of the patients were referred for further diagnosis and 9 % for further treatment related to dental problems. CONCLUSION Incidental findings are common on CBCTs. Compared with the literature, CLP patients have more dental, nasal and ear problems. Thus, whenever a CBCT is available, this scan should be reviewed by all specialists in the CLP team focusing on their specific background knowledge concerning symptoms and treatment of these patients. CLINICAL RELEVANCE The high number of findings indicates that CBCT imaging is a helpful tool in the treatment of CLP patients not only related to alveolar bone grafting and orthognathic surgery but it also provides diagnostic information for almost all specialties involved in CLP treatment.

Diagnosis and interdisciplinary treatment of a botryoid odontogenic cyst in the posterior mandible: report of a case.

Botryoid odontogenic cysts (BOC) are considered to be rare polycystic variants of lateral periodontal cysts characterized by a multilocular growth pattern. The most frequent location of BOC is the mandible, predominantly the premolar-canine area, followed by the anterior region of the maxilla. The cyst shows a slight female predilection. This case report of a BOC demonstrates a treatment with initial fenestration and decompression of the cyst in order to prevent damage to adjacent structures such as the inferior alveolar nerve. The present case report emphasizes the importance of accurate clinical, radiographic, and histologic diagnostic procedures of unspecific radiolucent lesions in the jaws to establish a firm diagnosis and avoid inappropriate treatment strategies.

Experimental peri-implant mucositis at different implant surfaces

OBJECTIVES To histologically and immunologically assess experimental peri-implant mucositis at surface enhanced modified (mod) hydrophilic titanium implants. MATERIALS AND METHODS In a split-mouth design (n = 6 foxhounds), four different implants were inserted on each side of the maxilla: three titanium-zirconium alloy implants (TiZr) with either modSLA (sand-blasted, acid etched and chemically mod), modMA (machined, acid etched and chemically mod), or M (machined) surfaces in the transmucosal portion, and one titanium implant with a machined transmucosal portion (TiM). Experimental mucositis was induced at one randomly assigned side (NPC), whereas the contra-lateral maxillary side received mechanical plaque removal three times per week (PC). At 16 weeks, tissue biopsies were processed for histological (primary outcome: apical extension of the inflammatory cell infiltrate measured from the mucosal margin - PM-aICT) and immunohistochemical (CD68 antigen reactivity) analyses. Peri-implant sulcus fluid was analysed for interleukin (IL)-1β, IL-8, matrix metalloproteinase (MMP)-8 and myeloperoxidase (MPO). RESULTS Mean PM-aICT values varied between 1.86 (TiZrmodSLA) and 3.40 mm (TiM) in the UPC group, and between 0.88 (TiZrmodSLA) and 2.08 mm (TiZrM) in the PC group. Mean CD68, IL-1β, IL-8, MMP-8 and MPO values were equally distributed between mod- and control implants in both NPC and PC groups. CONCLUSIONS The progression of experimental mucositis was comparable at all implant surfaces investigated.

Optimal number of oral implants for fixed reconstructions: a review of the literature.

BACKGROUND AND AIM So far there is little evidence from randomised clinical trials (RCT) or systematic reviews on the preferred or best number of implants to be used for the support of a fixed prosthesis in the edentulous maxilla or mandible, and no consensus has been reached. Therefore, we reviewed articles published in the past 30 years that reported on treatment outcomes for implant-supported fixed prostheses, including survival of implants and survival of prostheses after a minimum observation period of 1 year. MATERIAL AND METHODS MEDLINE and EMBASE were searched to identify eligible studies. Short and long-term clinical studies were included with prospective and retrospective study designs to see if relevant information could be obtained on the number of implants related to the prosthetic technique. Articles reporting on implant placement combined with advanced surgical techniques such as sinus floor elevation (SFE) or extensive grafting were excluded. Two reviewers extracted the data independently. RESULTS A primary search was broken down to 222 articles. Out of these, 29 studies comprising 26 datasets fulfilled the inclusion criteria. From all studies, the number of planned and placed implants was available. With two exceptions, no RCTs were found, and these two studies did not compare different numbers of implants per prosthesis. Eight studies were retrospective; all the others were prospective. Fourteen studies calculated cumulative survival rates for 5 and more years. From these data, the average survival rate was between 90% and 100%. The analysis of the selected articles revealed a clear tendency to plan 4 to 6 implants per prosthesis. For supporting a cross-arch fixed prosthesis in the maxilla, the variation is slightly greater. CONCLUSIONS In spite of a dispersion of results, similar outcomes are reported with regard to survival and number of implants per jaw. Since the 1990s, it was proven that there is no need to install as many implants as possible in the available jawbone. The overwhelming majority of articles dealing with standard surgical procedures to rehabilitate edentulous jaws uses 4 to 6 implants.

Patient-reported outcomes of maxillary implant-supported overdentures compared with conventional dentures

OBJECTIVE The aim of the present prospective clinical study was to compare patient-reported outcomes for maxillary conventional dentures and maxillary implant-supported dentures. MATERIAL AND METHODS Twenty-one patients (6 women and 15 men) being edentulous in the maxilla and encountering problems with their existing dentures were included. Twelve patients (4 women and 8 men) received a new set of conventional dentures, due to insufficient dentures. In nine patients (2 women and 7 men), the existing dentures were adjusted by means of relining or rebasing. All patients received implant-supported dentures on two retentive anchors. In total, 42 implants were inserted in the anterior maxilla. The participants rated their satisfaction on their existing conventional dentures, 2 months after insertion of new conventional dentures and 2 months after insertion of implant-supported dentures. Thereby, patients responded to questionnaires capturing the oral health impact profile (OHIP) using visual analog scales. Seven domains (functional limitation, physical pain, psychological discomfort, physical, psychological and social disability and handicap) were assessed. Higher scores implied poorer patient satisfaction. In addition, the questionnaire involved the evaluation of cleaning ability, general satisfaction, speech, comfort, esthetics, stability, and chewing ability. Higher scores implied higher patient satisfaction. RESULTS Patient satisfaction significantly increased for implant-supported dentures compared with old dentures in all seven OHIP subgroups, as well as for cleaning ability, general satisfaction, ability to speak, comfort, esthetics, and stability (P < 0.05). The comparison of new conventional dentures and implant-supported dentures revealed a statistically significantly increased satisfaction for functional limitation (difference of 33.2 mm), psychological discomfort (difference of 36.7 mm), physical disability (difference of 36.3 mm), and social disability (difference of 23.5 mm), (P < 0.05). Additionally, general satisfaction, chewing ability, speech, and stability significantly improved in implant-supported dentures (P < 0.05). CONCLUSIONS Within the limits of this study, maxillary dentures retained by two implants provided some significant short-term improvements over conventional dentures in oral- and health-related quality of life.

Morphologic characteristics, location, and associated complications of maxillary and mandibular supernumerary teeth as evaluated using cone beam computed tomography.

OBJECTIVES To evaluate the location and morphologic characteristics of supernumerary teeth and to assess the frequency and extent of root resorption of adjacent teeth using cone beam computed tomography (CBCT). MATERIALS AND METHODS CBCT scans of 82 patients with supernumerary teeth in the maxilla and mandible were evaluated by two orthodontists independently. Data regarding the type, shape, and three-dimensional (3D) location of the supernumeraries including the frequency and extent of root resorption of adjacent teeth were recorded and evaluated for possible associations. RESULTS The study comprised a total of 101 supernumerary teeth. Most of the patients (80.5 per cent) exhibited one single supernumerary tooth, while 15.8 per cent had two and 3.7 per cent had three supernumeraries. Males were affected more than females with a ratio of 1.65:1. Mesiodentes were the most frequently diagnosed type of supernumerary teeth (48.52 per cent), followed by supernumerary premolars (23.76 per cent) and lateral incisors (18.81 per cent). Supernumeraries were most commonly conical in shape (42.6 per cent) with a normal or inclined vertical position (61.4 per cent). Root resorption of adjacent teeth was detected for 22.8 per cent of the supernumerary teeth, most frequently for supernumerary premolars. There was a significant association between root resorption of adjacent teeth and type and shape of tooth. Interrater agreement for the measurements performed showed kappa values ranging from 0.55 to 1 with a kappa value of 1 for type and shape of the supernumerary teeth. CONCLUSIONS CBCT provides 3D information about location and shape of supernumerary teeth as well as prevalence and degree of root resorption of neighbouring teeth with moderate to high interrater correlation.

Do executive dysfunction and freezing of gait in Parkinson's disease share the same neuroanatomical correlates?

Current hypotheses postulate a relationship between executive dysfunction and freezing of gait (FOG) in Parkinson's disease (PD). Hitherto, most evidence comes from entirely clinical approaches, while knowledge about this relationship on the morphological level is sparse. The aim of this study was therefore to assess the overlap of gray matter atrophy associated with FOG and executive dysfunction in PD. We included 18 PD patients with FOG and 20 without FOG in our analysis. A voxel-based morphometry approach was used to reveal voxel clusters in the gray matter which were associated with FOG and executive dysfunction as measured by the Frontal Assessment Battery, respectively. Conjunction analysis was applied to detect overlaps of the associated patterns. FOG correlated with different cortical clusters in the frontal and parietal lobes, whereas those associated with the FAB scores were, although widespread, widely confined to the frontal lobe. Conjunction analysis revealed a significant cluster of gray matter loss in the right dorsolateral prefrontal cortex. We could show that the patterns of neurodegeneration associated with FOG and executive dysfunction (as measured by the FAB) share atrophic changes in the same cortical areas. However, there is also a considerable number of cortical areas where neurodegenerative changes are only unique for either sign. Particularly, the involvement of parietal lobe areas seems to be more specific for FOG.

Alveolar bone regeneration in response to local application of calcitriol in vitamin D deficient rats

AIM Vitamin D deficiency is considered to diminish bone regeneration. Yet, raising the serum levels takes months. A topic application of the active vitamin D metabolite, calcitriol, may be an effective approach. Thus, it becomes important to know the effect of vitamin D deficiency and local application on alveolar bone regeneration. MATERIAL AND METHODS Sixty rats were divided into three groups; two vitamin depletion groups and a control group. Identical single defects (2 mm diameter) were created in the maxilla and mandible treated with calcitriol soaked collagen in one deficiency group while in the other two groups not. Histomorphometric analysis and micro CTs were performed after 1 and 3 weeks. Serum levels of 25(OH)D3 and PTH were determined. RESULTS Bone formation rate significantly increased within the observation period in all groups. Bone regeneration was higher in the maxilla than in the mandible. However, bone regeneration was lower in the control group compared to vitamin depletion groups, with no significant effects by local administration of calcitriol (micro CT mandible p = 0.003, maxilla p < 0.001; histomorphometry maxilla p = 0.035, mandible p = 0.18). CONCLUSION Vitamin D deficiency not necessarily impairs bone regeneration in the rat jaw and a single local calcitriol application does not enhance healing.

A prospective, randomized, controlled study using OsseoSpeed™ implants placed in maxillary fresh extraction socket: soft tissues response

PURPOSE The aim of this work was to study the peri-implant soft tissues response, by evaluating both the recession and the papilla indexes, of patients treated with implants with two different configurations. In addition, data were stratified by tooth category, smoking habit and thickness of buccal bone wall. MATERIALS AND METHODS The clinical trial was designed as a prospective, randomized-controlled multicenter study. Adults in need of one or more implants replacing teeth to be removed in the maxilla within the region 15-25 were recruited. Following tooth extraction, the site was randomly allocated to receive either a cylindrical or conical/cylindrical implant. The following parameters were studied: (i) Soft tissue recession (REC) measured by comparing the gingival zenith (GZ) score at baseline (permanent restoration) with that of the yearly follow-up visits over a period of 3 years (V1, V2 and V3). (ii) Interdental Papilla Index (PI): PI measurements were performed at baseline and compared with that of the follow-up visits. In addition, data were stratified by different variables: tooth category: anterior (incisors and canine) and posterior (first and second premolar); smoking habit: patient smoker (habitual or occasional smoker at inclusion) or non-smoker (non-smoker or ex-smoker at inclusion) and thickness of buccal bone wall (TB): TB ≤ 1 mm (thin buccal wall) or TB > 1 mm (thick buccal wall). RESULTS A total of 93 patients were treated with 93 implants. At the surgical re-entry one implant was mobile and then removed; moreover, one patient was lost to follow-up. Ninety-one patients were restored with 91 implant-supported permanent single crowns. After the 3-year follow-up, a mean gain of 0.23 mm of GZ was measured; moreover, 79% and 72% of mesial and distal papillae were classified as >50%/ complete, respectively. From the stratification analysis, not significant differences were found between the mean GZ scores of implants with TB ≤ 1 mm (thin buccal wall) and TB > 1 mm (thick buccal wall), respectively (P < 0.05, Mann-Whitney U-test) at baseline, at V1, V2 and V3 follow-up visits. Also, the other variables did not seem to influence GZ changes over the follow-up period. Moreover, a re-growth of the interproximal mesial and distal papillae was the general trend observed independently from the variables studied. CONCLUSIONS Immediate single implant treatment may be considered a predictable option regarding soft tissue stability over a period of 3 years of follow-up. An overall buccal soft tissue stability was observed during the GZ changes from the baseline to the 3 years of follow-up with a mean GZ reduction of 0.23 mm. A nearly full papillary re-growth can be detectable over a minimum period of 2 years of follow-up for both cylindrical and conical/cylindrical implants. Both the interproximal papilla filling and the midfacial mucosa stability were not influenced by variables such as type of fixture configuration, tooth category, smoke habit, and thickness of buccal bone wall of ≤ 1 mm (thin buccal wall).

Three-year outcomes of Straumann Bone Level SLActive dental implants in daily dental practice: a prospective non-interventional study

OBJECTIVE The aim of this investigation was to evaluate the performance of Straumann Bone Level SLActive implants in various clinical situations in daily dental practice for up to 3 years. METHOD AND MATERIALS This was a prospective, multicenter, non-interventional study in which implants were placed within approved indications in any situation deemed suitable by the treating clinician. No implant placement or loading protocol was specified, and implants were placed according to the routine treatment protocols at each participating center. RESULTS In this analysis, data were available from 342 implants in 233 patients in three countries (USA, Canada, and Switzerland). One or two implants were placed in the majority of patients (70.8% and 19.3%, respectively), mostly in the maxilla (71.3%); almost half (47.7%) were placed in the esthetic zone. Implant placement after 4 to > 16 weeks of healing was preferred in Switzerland (92.0%), while 42.0% of implants were placed immediately in the USA and Canada. A flapless procedure was performed in 25.2% of cases in the USA and Canada, compared to 0.5% in Switzerland. Cumulative implant survival and success rates after 3 years were 97.5% and 93.5%, respectively. CONCLUSION Straumann Bone Level Implants can achieve favorable outcomes and high survival rates after 3 years in daily dental practice. The survival and success rates were comparable with those achieved in formal controlled clinical trials.

Stability of Le Fort I maxillary inferior repositioning surgery with rigid internal fixation: a systematic review

The aim of this study was to evaluate the stability of Le Fort I maxillary inferior repositioning surgery in patients with a vertical maxillary deficiency at least 6 months after surgery. The electronic databases were searched to identify all articles reporting the long-term effects of one-piece maxillary inferior repositioning with rigid fixation. Methodological quality was evaluated according to 15 criteria related to study design, measurements, and statistical analysis. Two articles were identified, with a total of 22 patients. The maxilla was repositioned inferiorly from a mean 3.2 to 4.5mm in the anterior part and from a mean 0.1 to 1.8mm in the posterior part. At 6 months post-treatment, absolute relapse of a mean 1.6mm was measured for the anterior part of the maxilla and 0.3mm for the posterior part of the maxilla. The stability of maxillary inferior repositioning surgery could not be confirmed due to the small sample size, unclear diagnosis, and potential confounding factors.

The timing of extraction of non-restorable first permanent molars: a systematic review.

AIM To identify the ideal timing of first permanent molar extraction to reduce the future need for orthodontic treatment. MATERIALS AND METHODS A computerised database and subsequent manual search was performed using Medline database, Embase and Ovid, covering the period from January 1946 to February 2013. Two reviewers (JE and ME) extracted the data independently and evaluated if the studies matched the inclusion criteria. Inclusion criteria were specification of the follow-up with clinical examination or analysis of models, specification of the chronological age or dental developmental stage at the time of extraction, no treatment in between, classification of the treatment result into perfect, good, average and poor. The search was limited to human studies and no language limitations were set. RESULTS The search strategy resulted in 18 full-text articles, of which 6 met the inclusion criteria. By pooling the data from maxillary sites, good to perfect clinical outcome was estimated in 72% (95% confidence interval 63%-82%). Extractions at the age of 8-10.5 years tended to show better spontaneous clinical outcomes compared to the other age groups. By pooling the data from mandibular sites, extractions performed at the age of 8-10.5 and 10.5-11.5 years showed significantly superior spontaneous clinical outcome with a probability of 50% and 59% likelihood, respectively, to achieve good to perfect clinical result (p<0.05) compared to the other age groups (<8 years of age: 34%, >11.5 years of age: 44%). CONCLUSION Prevention of complications after first permanent molars extractions is an important issue. The overall success rate of spontaneous clinical outcome for maxillary extraction of first permanent molars was superior to mandibular extraction. Extractions of mandibular first permanent molars should be performed between 8 and 11.5 years of age in order to achieve a good spontaneous clinical outcome. For the extraction in the maxilla, no firm conclusions concerning the ideal extraction timing could be drawn.

Complications with computer-aided designed/computer-assisted manufactured titanium and soldered gold bars for mandibular implant-overdentures: short-term observations

BACKGROUND Implant-overdentures supported by rigid bars provide stability in the edentulous atrophic mandible. However, fractures of solder joints and matrices, and loosening of screws and matrices were observed with soldered gold bars (G-bars). Computer-aided designed/computer-assisted manufactured (CAD/CAM) titanium bars (Ti-bars) may reduce technical complications due to enhanced material quality. PURPOSE To compare prosthetic-technical maintenance service of mandibular implant-overdentures supported by CAD/CAM Ti-bar and soldered G-bar. MATERIALS AND METHODS Edentulous patients were consecutively admitted for implant-prosthodontic treatment with a maxillary complete denture and a mandibular implant-overdenture connected to a rigid G-bar or Ti-bar. Maintenance service and problems with the implant-retention device complex and the prosthesis were recorded during minimally 3-4 years. Annual peri-implant crestal bone level changes (ΔBIC) were radiographically assessed. RESULTS Data of 213 edentulous patients (mean age 68 ± 10 years), who had received a total of 477 tapered implants, were available. Ti-bar and G-bar comprised 101 and 112 patients with 231 and 246 implants, respectively. Ti-bar mostly exhibited distal bar extensions (96%) compared to 34% of G-bar (p < .001). Fracture rate of bars extensions (4.7% vs 14.8%, p < .001) and matrices (1% vs 13%, p < .001) was lower for Ti-bar. Matrices activation was required 2.4× less often in Ti-bar. ΔBIC remained stable for both groups. CONCLUSIONS Implant overdentures supported by soldered gold bars or milled CAD/CAM Ti-bars are a successful treatment modality but require regular maintenance service. These short-term observations support the hypothesis that CAD/CAM Ti-bars reduce technical complications. Fracture location indicated that the titanium thickness around the screw-access hole should be increased.