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Success and Survival Rates of Teeth Restored with Cast Post and Core among National Guard Health Affairs Patients, Riyadh, Saudi Arabia- Juniper Publishers

Success and Survival Rates of Teeth Restored with Cast Post and Core among National Guard Health Affairs Patients, Riyadh, Saudi Arabia

Authored by Abeer A Al Subait

Abstract

Purpose:To determine the success and survival rates of endodontically treated teeth restored with cast post and core among NGHA patients in Riyadh, Saudi Arabia.

Materials and Methods:This retrospective study was conducted in King Abdulaziz Dental Centre (KADC) in Riyadh during November 2015 – April 2016. Fifty seven patients with 140 intraradicular cast posts were included. Patients were evaluated both clinically and radiographically according to the FDI criteria for the evaluation of direct and indirect restorations by two independent examiners, one examiner for the radiographic and another for the clinical examination, after obtaining a well-written and explained informed consent form.

Results: Of 140 endodontically treated teeth restored with cast post and core, 65 (46.4%) teeth showed one or more of the radiographic failure and 76 (54.3%) showed one or more clinical sign of failure. The accumulative failure rate was 72.9 % which include relative failure of 45.0% and absolute failure of 27.9%. The majority of the radiographic failure involve; periapical lesion 30.7% and recurrent caries 24.3%. The majority of the clinical failure involve; dental caries 19.3% and periodontal pocket of more than 4mm 19.3%. The survival and success rate were 27.1% and 72.1% respectively.

Conclusion: Numerous complications and high failure rate were noted among endodontically treated teeth restored with cast post and core. This raise a question about the validity of selecting cast post and core to restore endodontically treated teeth in the presence of other advanced and recent alternative intraradicular retention systems. However, retrospective nature and small sample size caution us to conclude our findings. Further randomized clinical trials are needed with long term follow up period to build upon the findings of this study.

Keywords: Gingival recession; Core debonding; Post and core restorations; Incisors; Premolars

Abbreviations: ASA: American Academy of Anesthesiology; NGHA: National Guard Health Affairs; KADC: King Abdulaziz Dental Centre

Introduction

Endontically treated teeth usually require intraradicular restoration for retention aspects due to extensive loss of tooth structure resulting from caries, trauma and access cavity preparation. Post and core restorations are usually used in root canal treated teeth that require additional measures in order to receive optimum restorations that adequately serve both functional and aesthetic purposes. Post and core restorations with their different systems were suggested as a successful method to increase retention for the coronal restoration [1]. The most critical factor in avoiding complication with intraradicular retention is preserving tooth structure [2,3]. In the past, the most widely used post and core system was metal cast post and core [4,5]. Furthermore, according to some, cast post and core intraradicular retention system is still considered the established technique or gold standard post system for restoring extensively damaged and endodontically treated teeth [6,7]. This treatment modality has maintained its popularity and credibility throughout the years. Custom-fabricated post and cores using a standardized fabrication technique have shown a good long-term prognosis with an average survival time of 7.3 years [8]. Despite its popularity, cast post and core still has many disadvantages such as root fracture, periapical lesion, and dislodgment [9].

Furthermore, the introduction of other post systems with comparable success and survival rates provides an alternative to cast post system for root canal treated teeth [5]. Multiple in vivo studies concluded low success rate and higher failure for cast post and core such as in Ferrari et al in 1995, who found that cast post and core showed high percentage of failure 14% and low success rate 84% [9]. In 2007 found that failure rates of 8.82% were observed in the cast metal post after 4 years of clinical service [10]. Another study of GA Preethi et al. [11] found that the success rate of the cast post and core was 90% after only one year [11]. The range of survival rates of cast post and core - according to Fokingga et al. [3] was between 78-94% [3]. Also in a number of in vitro studies they found that the fracture resistance of cast post and core is not the highest as has been advocated by clinical expertise as demonstrated by Giovanni A et al. [12]. Abduljabbar T et al. [13] found that the average load required to fracture cast post & core systems was 541.2 N which is relatively comparable to other systems.

Concerning fracture patterns, variety of studies showed that most fracture patterns are usually unfavorable if they occur when using cast post & core where fractures occurred in the tooth structure [14]. In addition, Abduljabbar T et al. [13] concluded that 90% of fracture patterns of teeth restored with cast post and core were unfavorable (i.e. tooth is not restorable) [13]. In the same topic a study was done by Salameh Z et al. [15] concluded that teeth restored with cast post and core were significantly more associated with unfavorable fracture with a percentage of more than 50% of the study sample. Regarding the success rate in relation to the type of tooth, GA Preethi et al. [11] in 2008 found that cast post and core has the least success rate when used in single rooted upper anterior teeth. While in an in vitro study done by C.G. Castro et al. [16] studied if the type of tooth had any effect in the fracture resistance, He found that canines and molars had significantly higher values of fracture resistance than incisors and premolars. The aim of this study is to determine the survival and success rates of endodontically treated teeth restored with cast post and core among patients of National Guard Health Affairs, Riyadh, Saudi Arabia.

Methodology

This retrospective study was conducted in King Abdulaziz Dental Centre (KADC) in Riyadh during November 2015 to April 2016. All medical record numbers for patients who received cast post and cores were obtained from dental lab in KADC. Five hundred and forty files were chosen using a simple random sampling. Patients’ records were reviewed after obtaining the permission from medical records department in KAMC. Based on our inclusion and exclusion criteria sample size was 169 patients.

We excluded all those patient files which had insufficient information about the demographic data or contact information, pregnant females and those who had other types of cement. Fifty seven patients with 140 intraradicular cast posts were included in this retrospective study. During the review of the included files, information of age of the post, number of treated teeth, type of cement, type of coronal restoration and whether the treatment provider is a specialist or a resident were recorded using special form. The selected patients were contacted by phone and invited to participate in the study. The patients were provided with the details of the evaluation. Subjects were invited to KADC clinics for examination. Patients were evaluated both clinically and radiographically according to the FDI criteria for the evaluation of direct and indirect restorations by two independent examiners after obtaining a well-written and explained consent form [17].

Every endodontically treated tooth with intraradicular cast post and core system was evaluated both radiographically and clinically. Radiographically by an intraoral periapical radiograph taken by paralleling technique and interpreted for any recurrent caries, periapical lesions, root fracture and furcation involvement. Clinical examination done by using an explorer, periodontal probe (William’s probe) and mouth mirror. Moreover patients were investigated about any episodes of pain, pain on percussion, discomfort or bleeding related to the tooth of interest and patients’ oral hygiene was evaluated by using Silness and Loe plaque Index on Ramjford teeth. The assessment sheet included information on patient’s age, gender, American Academy of Anesthesiology (ASA) classification, tooth number and type and time the restoration had been in clinical service. All outcomes were categorized as relative or absolute failure. Any radiographic and clinical sign of failure was considered as absolute failure. While presence of either radiographic or clinical sign considered as a relative failure. Success was defined as absence of absolute and relative failure. Survival was defined as the absence of absolute failure [18,19]. Patients with failed post and cores were referred to the dental clinics for further management. The data were analyzed using SPSS software. A P value of 0.05 and less was considered statistically significant.

Results

In this study 140 teeth, of whom 91 (65%) belonged to female patients and 49 (35%) to male patients, were examined at the dental center of King Abdulaziz Medical City (Table 1). The age of the patients ranged between 17 to 82 years old with a mean age of 40 years. Eighty four (60%) patients claimed they do not have any medical condition, while 56 (40%) claimed to have at least one medical condition. Of the total teeth the majority of the teeth were molars and premolars – 103 (73.6%) – while 37 (26.4%) were incisors and canines The posterior teeth have higher failure rate comparing to the anterior teeth with the difference being statistically not significant (P=0. 071).Treatment was provided by either a specialist 92 (65.7%) or resident 48 (34.3%). The failure rate was higher among teeth which had been treated by resident however the difference being statically insignificant (P=0.348). Regarding smoking, 10 (17.6%) of the patients were smokers while 47 (82.4%) were nonsmokers. The failure in smokers was not statistically significant (P=0.193) when compared to nonsmoker patients. One of the major factors for having healthy dentition was good oral hygiene practice. The patients in this study had different oral hygiene status ranging from excellent 2 (3.5%), good 20 (35.1%), fair 28 (49.1 %) and poor 7(12.3%). The result showed that the difference in oral hygiene status had no significant effect in relation to the failure (P =0.999). The post were cemented using GIC, resin cement and zinc phosphate cement with a percentage of 79.3%, 4.3%,and 16.4% respectively. The difference among the different types of post cement in relation to the failure was not statistically significant (P=0.42). Ninety eight (70%) of the total teeth were restored with Porcelain Fused to Metal for single crowns while 9 (6.4%) were used as abutments for fixed partial denture. The other 33 (23.6%) teeth were left without a final restoration (Table 2). The final restoration showed insignificant difference (P =0.058) in relation to failure. The radiographic failure includes presence of one or more of the following: recurrent caries, periapical lesion, root fracture, and furcation involvement (Table 3). Sixty five (46.4%) of the teeth showed at least one of the radiographic failure signs. Thirty four (24.3%) of teeth have radiographic recurrent caries while 43(30.7%) have radiographic periapical lesion. Radiographic root facture and furcation involvement was in 1(0.7%) and 2(1.4%) teeth respectively Seventy six (54.3%) of the teeth showed one or more signs of the clinical failure which include: spontaneous pain, tenderness to percussion, caries, periodontal pocket of more than 4 mm, gingival recession, post and core debonding, post and core fracture, furcation involvement, mobility of post (Table 4). Only 3(2.1%) of the teeth had spontaneous pain while 4(2.9%) teeth were tender to percussion while 27(19.3%) teeth showed signs of recurrent caries clinically. Regarding periodontal problems, 27(19.3%) teeth have periodontal pocket more than 4mm while 17(12.1%) teeth have gingival recession. Nine (6.4%) of the post were debonded where 16(11.4%) of the post were mobile. Neither post and core fracture nor furcation Involvement was seen. The total failure rate which includes both absolute and relative failure was in 72.9 % of the teeth.

The absolute failure includes both clinical and radiographic failure and the rate was 27.9%. While the relative failure involves all teeth that have either clinical or radiographic failure the rate was 45.0%. On the other hand, teeth which did not show any sign of clinical and radiographic failure were consider succeeded. The success rate of the total sample size was 27.1% (Figure 1) while the survival rate was 72.1%.

Discussion

This retrospective study was conducted on 140 teeth belongs to both male and female subjects and aimed to determine the survival and success rates of endodontically treated teeth restored with cast post and core .The success rate was around one third of the total sample while the survival rate exceeded two thirds. Regarding the absolute and relative failure rates, they were observed among one third and half of the study sample respectfully. Failure rates due to caries and periodontal pockets were the highest among the teeth having clinical failure while periapical lesions were the most prevalent cause of radiographic failure.

The strength of the present study include: the level to which inclusion and exclusion criteria were set to meet, the informed consent which was obtained from all subjects, both male and female participants were included with multiple diversities and variations, examination was done both clinically and radiographically according to FDI criteria, patients that required further treatment and management were referred to be treated per complaint and at the end, outcomes of the study were clearly defined and all predictors for failure were analyzed. Regarding the sample distribution, the majority of our sample belongs to a middle age group who are classified as ASAI due to the fact that our study is both clinically and radiographically based which requires the presence of the patient in dental office that may be a challenge to elderly and/or patients with serious medical problems. Furthermore, most of the samples were posterior teeth restored with PFM crowns which are because posterior teeth have relatively less esthetic demands and require load-bearing restorations [20].

The high survival rate shown in our study goes along with what was proven by other studies as in Balkenhol et al. [21] which concluded that the survival probability of cast post and cores reaches up to 7.3 years. Also, Heydecke et al. [1] in his literature review mentioned that survival of cast post and cores ranges from 87.2 to 88.1%. The failure rates which were observed more in female patients who constituted the bulk of the study sample contradicts what was mentioned in Hikasa et al. [22] where he stated that failure rates of cast metal posts and cores are more associated with males rather than females. In the same study it was mentioned that the higher the age of the patient at the cementation of the cast post and core the higher the failure rates observed which is in accordance with our findings.

The relative high survival rate showed in this study in the posterior teeth restored with cast post and core has been noted by Mentink et al. [7] who reported high survival rated among posterior teeth. The relative high failure rates observed among teeth treated by residents can be due to the wrong case selection and treatment planning errors as shown in Sarkis et al. [23] who concluded that dentists without post-graduate training used cast post and core more frequently as their first choice.

Although it was not statistically significant, smoking was more associated with higher failure rates, this can be explained by Tomar et al. [24] and Jang Ay et al. [25] where they found that smoking constitutes a risk factor for periodontal disease which may affect the longevity and survival of affected teeth. All teeth-related and patient-related factors addressed in this study such as type of tooth, final restoration, type of cement used, oral hygiene status and the ASA classification of the patients showed no influence on the success and survival rates. This can be explained in one way or another by the small sample size of the study which was the result of our restricted inclusion criteria requiring meticulous details in the documentation of each case.

When comparing the failure rates between the different cements included in this study, GIC had the most failure rates which contemplates what was mentioned in Zheng et al. [26] where he concluded that using GIC cement significantly aggravates coronal microleakage. The low success rate can be attributed to the fact that teeth requiring intracranial retention are usually severely destructed with little or no coronal structures which further compromises their long term prognosis as shown in Ferrari et al. [19]. In fact, most of our sample had fair to poor oral hygiene and reported that there were no follow up appointments which indicates that there weren’t any kind of maintenance that is recommended in complex treatments involving multidisciplinary interventions.

All teeth-related and patient-related factors addressed in this study such as type of tooth, final restoration, type of cement used, oral hygiene status and the ASA classification of the patients showed no influence on the success and survival rates. This can be explained in one way or another by the small sample size of the study which was the result of our restricted inclusion criteria requiring meticulous details in the documentation of each case. The resultant success and survival rates were influenced by the fact that different treatment phases were done by different providers from the endodontic treatment through prosthodontic procedures and restorations. However, the sample included only teeth treated according to standards protocol which were illustrated in the patient file. Nevertheless retrospective nature of study caution us to conclude our findings as there are many factors that could have resulted in endodontic failure. As survival rates depend upon tooth structure, cause of RCT, operator technique, sourced of contamination, type and quality of post and coronal restoration. Many of these factors are not studied in this present study.

Moreover the method in which this study was conducted limits us in matters of sampling and insurance of optimum dental management throughout the different phases subsequent to and after cementation of the cast post and cores. So, a randomized clinical trial raising the same question with better sampling techniques and more involvement in all treatment steps would carry out highly reliable results and interpretations which can be of benefits in understanding the value of this treatment modality in relation to all alternatives and how it can be provided in high quality manner.

Conclusion

Numerous complications and high failure rate were noted among endodontically treated teeth restored with cast post and core. This raise a question about the validity of selecting cast post and core to restore endodontically treated teeth in the presence of other advanced and recent alternative intraradicular retention system. However, retrospective nature and small sample size caution us to conclude our findings. Many other factors are needed to be explore as failure rates are highly dependent on many vital factors related to the tooth structure, reason for RCT, time span, type of techniques used by clinician and many other factors that can confound study results. Nevertheless Further randomized clinical trials are needed with long term follow up period to build upon the findings of this study.

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The Effect of Various Classes of Malocclusions on the Maxillary Arch Forms and Dimensions in Jordanian Population- Juniper Publishers

Authored by Raghda Al Shammout

Abstract

Aim: The objective of this study was to determine the differences of clinical maxillary arch forms in Angle Class I, II, and III using arch dimension parameters.

Materials and method: A total of 124 (76 females and 48 males) fully dentate Jordanian subjects (mean age=18.34±4.26; range=14-22 years) were clinically examined and divided into 3 groups according to Angle’s classifications (Class I, II and III). Study casts were made and measured for 4 linear measurements of maxillary cast dimensions were taken (Inter-canine and inter-molar widths; and canine and molar depths). Canine W/D and molar W/D ratios were calculated. Arch form was determined according to measurements and related to occlusal pattern. The commonest malocclusion was class I (54.8%), followed by class II (37.9%) and class III (7.3%). Statistically significant differences were recorded in arch widths (p<0.05); Class III maxillary dental arches (W=37.8mm) were narrower than Class I (W=38.9 mm) and Class II dental arches (W=40.6mm) were the widest. In Class I: 55% of arches were ovoid, 40% tapered and 5% square. In Class II: 73% tapered 24% ovoid, and 3% square. In Class III: 45% tapered, 35% ovoid and 20% square. Measurements were significantly (p<0.05) higher in males than in females. No gender differences in canine and molar W/D ratios were recorded. Although more males had Class III, more females had Class II arches but the differences were not significant.

Conclusion: Before orthodontic treatment, the arch form should be determined in relation with patients’ occlusal pattern to achieve best esthetic, functional and stable arch form out-come.

Keywords: Arch form; Angle’s classification; Malocclusion; Maxillary Arch; Orthodontics

Introduction

The dental arch form is defined as the curving shape formed by the configuration of the bony ridge [1]. Arch form, dimension and variations obtained by orthodontic treatment has been studied for many years by several authors [2-4]. Consideration of the arch form is of paramount importance, because it is imperative that the arch form should be examined before embarking upon the treatment as this gives valuable information about the position into which teeth can be moved if they are to be stable following treatment [5].

Different methods have been developed to describe the dental arch morphology ranging from simple classification of arch shape [6] through combinations of linear dimensions [7,8] to complex mathematical equations [9,10].

In 1932, Chuck [11] classified the arch forms as tapered, ovoid and square for the first time. These arch forms can also be expressed as narrow, normal and wide [6]. Especially in determining the arch wire forms utilized at the initial phase of the treatment, he advocates that making a choice between these three forms would be better than using a single arch form [7]. The arch form should be determined in relation with each patients’ pre-treatment dental model and especially in relation with each patients’ ethnic group in order to achieve an esthetic, functional and stable arch form out-come [5,7].

Several researchers recognize that there is variability in the size and shape of arch form in relation to Angle’s classes of malocclusion [5,7,8,12-18]. In addition, the width, length and depth of dental arches have had considerable implications in orthodontic diagnosis and treatment planning in a modern dentistry based on prevention and early diagnosis of oral disease [4,19-22].

Several researchers studied the mandibular arch [5-8,14,18,22-25] while some others studied the maxillary arch [2,13,21,26] however, many others studied both arches [1,3,4, 9-11,12,15-20,27-31].

With the availability of different preformed shapes and sizes of arch wires, different studies highlighted the importance of selection of patients clinical arch form and customization of arch wire [5,8] in addition, determination of arch shape may be used as a guide to fabricate customized arch wires, or even an entire fixed orthodontic appliance system [29].

The importance of this study comes from the fact that studies investigating the differences in the maxillary arch forms in various types of Angle’s classes are scarce. Therefore, the present study may serve as population study and a database for future comparisons and to obtain baseline information on the morphological arch dimensions of the fully dentate population since these variations highly influence orthodontic and prosthetic rehabilitation of patients.

The differences in various types of Angle’s classification (Class I, II, and III) may cause changes in relation to the clinical maxillary arch forms and variations in its dimension. Therefore, it was hypothized that maxillary arch dimensions and morphology is not affected by different types of Angle’s classes and between genders.

Although there have been studies one on the evaluation of arch forms in various groups, to the authors’ knowledge, no such research has been performed on the Jordanian population; thus this study aimed to determine the differences of clinical maxillary arch forms in Angle Class I, II, and III in the Jordanian population by identifying its morphological variations and to evaluate gender differences with respect to arch dimension parameters.

Materials and Method

A cross-sectional study of Jordanian males and females who are fully dentate with different arch skeletal patterns, in the City of Amman who attended the Orthodontic Clinic, Outpatients Clinics, Department of Dentistry, Al-Hassan Hospital, King Hussein Medical Center, Royal Medical Services. A random sample for the study were selected from the general population, who fulfilled objective diagnostic criteria and exposed to clinical oral and dental examinations.

Ethical approval

FThe study was conducted for all patients who provided verbal informed consent after it was approved by Head of the Dental Specialities of the Department of Dentistry and The Human Research Ethics Committee (No.1/2014 dated 6th January 2014) at the Royal Medical services.

Inclusion/exclusion criteria

Subjects with different age groups who accepted to participate were fully dentate with no dental anomaly and with no history of congenital abnormality, those who were not exposed to any orthognathic surgical procedure, no missing tooth/teeth and with no extensive restorative procedure (i.e. crown and bridge work); and accepted to undergo clinical oral and dental examination, were able to understand and agreed with procedures carried out and used (such as taking alginate maxillary impressions) in the study and who were willing to accept the protocol and gave informed consent were included. Exclusion criteria were subjects with history of orthognathic surgery, missing teeth, crown and bridge work, removable partial denture prostheses, as well as those who did not agree to participate.

Participants

A total of 124 (76 females and 48 males) fully dentate Jordanian subjects with mean age of 18.3±4.3 (ranged between 14 and 22) years; were clinically examined and divided into 3 groups according to Angle’s classifications (Class I, II and III).

All recruited patients were subjected to clinical examination, a specially designed form concerning the patient’s demographic data including age, gender, medical insurance number, occupation and residence was filled by one of the authors.

Measurements

For each participant, alginate impression of the maxillary arch was taken, and poured in dental stone to form a stone cast (positive replica).

A stone cast was then made and marked with five reproducible reference points (with a 2H pencil), these were: mid-mesioincisal edges of central incisors, canine tips, mesiobuccal cusp tips of the first permanent molars used to perform measuring four linear measurements (Figure 1).

   Inter-canine width (ICW):The distance between right and left canines, measured from the tip of the canine tooth.

        Inter-molar width (IMW):The distance between the right and left first molars, measured from the highest point on the mesiobuccal cups of upper first molar tooth.

Canine depth (CD):The shortest distance from a line connecting the canines to the origin between the central incisors.

Molar depth (MD):The shortest distance from a line connecting the first molars to the origin between the central incisors.

Two proportional ratios were calculated:

   Canine Width/Depth (Wc/Dc) ratio:the ratio of the inter-canine width and the canine depth.

        Molar Width/Depth (Wm/Dm) ratio:the ratio of the inter-molar width and the molar depth.

All measurements were performed using Fowler electronic digital caliper (Figure 2), the accuracy of the measurements was set at ±0.01 mm.

Arch form was determined mathematically according to a formula [(Wc/Wm) / (Dc/Dm)] using the values obtained from the measurements. The mean measured data on the maxillary arch was used to determine the arch form and related to occlusal pattern (Figure 3).

When the Wc/Wm ratio increases or the Dc/Dm ratio decreases, the arch becomes squarer. On the contrary, when Wc/ Wm ratio decreases or Dc/Dm ratio increases, the arch gets a more tapered form. Therefore, the formula is used to describe the arch form.

When this ratio of a dental arch is within the range of mean±1 SD, we can assume the arch form is ovoid. However, when this ratio for an arch form is more than mean+1 SD, we can consider the arch form as square. Finally, when the ratio is less than mean +1 SD, we can consider the arch form as tapered [9].

Methods error

Reliability of examiners was assessed by examining internal consistency and reproducibility. Clinical examinations and measurements were performed by two independent examiners (66 subjects from one examiner and 58 from another examiner). They used the same orthodontic evaluation in the clinical examination for classifying occlusal relationship and standard method in the measurements. Inter-examiner variability and bias in evaluation were assessed by performing clinical examination 15 (12.1%) randomly selected subjects and re-measuring their casts by each examiner. Student’s t-test were performed for inter-examiner reliability evaluation.

Statistical analysis

Statistical analysis was performed using SPSS Statistic Version 17 (SPSS Corporation, Chicago, IL, USA). Chi square and Student’s t-test were used to compare the means of dimension measured on the casts between different age groups and in both genders. In addition, one-way ANOVA was used for the comparisons between different arch forms and the skeletal patterns. Ninety-five percent confidence intervals about the mean were constructed for differences. Level of significance was set at 0.05.

Results

Paired t-test revealed no statistically significant deviation between the examiners’ clinical examination evaluation at a 5% significance level (in 100%). Paired t-test revealed no statistically significant deviation between the examiners’ measurements at a 5% significance level (mean difference 1.98±0.15; p=0.942). As there was strong association and small mean difference between the two examiners, it was assumed that the other data collected from clinical examinations and measurement evaluations would be reliable.

A total of 124 fully dentate Jordanian subjects with mean age of 18.3±4.3 years (ranged between14 and 22) years. There were 48 (38.7%) males with mean age 18.7±4.7 (ranged 15-22) and 76 (61.3%) females with mean age 18.0±4.1 (ranged 14- 21) years. Females were slightly younger than males, but the difference were not significant (t-test=0.47; p=0.95).

The commonest class was class I (54.8%), followed by class II (37.9%) and class III (7.3%). Significantly, more females had Class I (p<0.01) and Class II (p<0.05) occlusal relationship compared with males. On the contrary, more males had Class III relation compared with females but the differences were not statistically significant (Table 1).

(Table 2) shows the gender differences in the mean canine and molar width and depth measurements and width: depth ratios. The mean values of all width and depth measurements were significantly (p<0.05) higher in males than in females. However, no gender differences in canine and molar W/D ratios were recorded. (Figure 4) shows the relationship between the mean values of inter-canine and inter-molar widths, canine and molar depths and W:D ratios with age. All width and depth measurements increased with age, inter-molar measurements recorded the steepest increase with age.

Statistically significant differences were recorded in arch width measurements (p<0.05). Class III arches, (Wc=33.7±2.7mm and Wm=49.5±4.1) are narrower than Class I (Wc=34.3±2.1mm and Wm=50.2±3.6) (p<0.01) and Class II dental arches (Wc=34.8±2.5mm and Wm=52.1±2.8) are the widest (p<0.05). However, there were no statistical significant differences between different classes in depth and width: depth ratios. (Table 3).

NS: Not Significant; *p<0.05; **p<0.01, aand b denotes sig. category from the mean (Bonferroni test, ANOVA).

SD: Standard Deviation; IC: Inter-Canine; IM: Inter-Molar; Wc/Dc: canine width:depth ratio; Wm/Dm: molar width:depth ratio

(Table 4) shows the distribution of participants’ arch form (square, tapered and ovoid) according to Angle’s classification.

Analyses of data according to the mathematical formula show that 52.4% of subjects have tapered maxillary arches and 41.1% ovoid. However, the least common arch form is the square which is recorded in only 6.5%. The commonest arch form in class I was the ovoid followed by tapered, however, in class II and class III subjects, the commonest arches were tapered.

Discussion

This study was conducted to determine the differences of clinical maxillary arch forms in Angle Class I, II, and III using arch dimension parameters, the sample was representative of a group of Jordanian population of dental patients that attended conservative and orthodontic dental clinics for a period of 6 months.

The size and shape of the dental arches have considerable implications for orthodontic diagnosis and treatment planning. These have an effect on the space availability, stability of dentition, esthetics and health of the periodontium [5].

In this study, more than 60% of the participants were women, although there was no statistically significant difference in the mean age between genders, women were slightly younger than men. In addition, the age distribution was limited with 14-22 in order to eliminate the variations in arch dimensions related with age. In addition, the age-related changes in the mean values of inter-canine and inter-molar width and depth measurements and W: D ratios shows a little gradual increase with age, however, the inter-molar measurements recorded the steepest increase with age.

After examining the differences in arch width in relationship with age, Bishara et al. [32] stated that although they had observed a reduction in canine width between 13-26 and 26- 45 in men and women, only the reduction detected in women between 26-45 was statistically important. Even though there is an increase in mandibular canine width until 13 years; this increase is found to be statistically important in boys until 8 and in girls until 13 years of age. After 13 years of age, the canine width shows a reduction in 25 and 45 years. In Bishara’s study the inter-molar width did not show a significant change between 13-26 and 26-45 years.

In the present study, gender-related differences were recorded in all arch width and depth measurements. When comparing arch dimensions with regard to gender, it was found that they are remarkably higher in males than females. These findings are in accordance with a previous study [33]. In an evaluation of arch width and depth measurements, it has been reported that these values are 3%-5% higher in boys [27]. It has been stated that the arch depth decreases in canine, first and second premolar and first molar teeth area in both genders [34].

The results that showed no differences in boys and girls were reported previously [18]. In most of the studies, although the values are less in girls, there is a relationship with the gender and arch dimension of the samples. It was postulated that there were significant differences related with gender only in the transversal dimensions [35]. In present study even though there are significant differences with respect to gender and canine/ molar width, both of the measurements are found to be higher in boys. Although boys possess a wider arch form than girls, there is an overall agreement that there is no gender variance with respect to arch form [36]. As it can be derived from these results, no statistically significant variances were found between gender and arch form.

The results of this study demonstrated that 54.8% of subjects were class I, 37.9% class II and the least (7.3%) were class III. In addition, significantly, more females had Class I and Class II occlusal relationship compared with males. On the contrary, more males had Class III relation compared with females but the differences were insignificant.

Similar findings were reported by Murshid [8] who found that class I was most prevalent (58.2%), followed by class II (32.7%) and class III (5.7%), in addition, it was reported that 58% were class I, 40% were class II and only 2% were class III [18]. However, Tajic et al. [5] reported that class II was the most prevalent (47.5%) followed by class I (45.8%) and the least was class III (6.7%). These differences could be attributed to racial variation in study samples.

Upon examination of the arch dimension differences between Angle classes, this study revealed statistically significant differences between classes in terms of arch width measurements (p<0.05). Class III arches were significantly narrower than Class I (p<0.01) and Class II dental arches were significantly the widest (p<0.05). However, the differences between different classes in depth and width: depth ratios were insignificant.

The molar width increase in Class II arches can be explained by buccal tipping of the anterior teeth in Class II development and flattening of the anterior area besides the lateral growth of the tongue due to the decrease of the molar depth [13,14]. In our study, when maxillary canine and molar depths were considered, no difference could be detected between Class I, II and Class III, also, upon comparison of these groups together in terms of width-depth ratios, no statistically significant differences were observed.

Arch shapes may also define characteristics of a particular occlusion group. Othman et al. [31] used tapered, square and ovoid arch form templates to evaluate the arch forms of angle class I, II and III. In this study, analyses of data according to the mathematical formula show that 52.4% of subjects have tapered maxillary arches and 41.1% ovoid. However, the least common arch form is the square which is recorded in only 6.5%. The findings of this study were similar to that reported in previous studies [7,12].

When comparing the arch form (square, tapered and ovoid) according to different classes, the commonest arch form in class I was the ovoid followed by tapered, however, in class II and class III subjects, the commonest arches were tapered. These findings strongly suggested that ovoid form should be considered when dealing with Class I cases and tapered form when Class II and III. The findings of this study are supported by the following previous studies [8,13,18].

The aim in specification of the arch form was to evaluate the final arch form which will be obtained by the use of fixed orthodontic appliances in patients who have referred to orthodontic clinic due to orthodontic malocclusion. In recent studies this arch form which is thought to be more realistic is preferred in determining the individual arch form [9,14].

Several studies used arch form templates for the evaluation of photo-copies of dental models, these are the 3 type of (narrow, normal and wide) arch forms specified by Paranhos et al. [6] and used by Chuck [11] for the first time in 1932. In this study, however, the maxillary arch form was determined mathematically using the values of width and depth obtained from the measurements [9,13].

The importance of this study is that determination of arch form in relation to different occlusal pattern is a prerequisite to orthodontic treatment in order to obtain the best outcome. As far as, esthetics is concerned, tapered arch form presents a better smile arc than square arch form which tends to provide a flatter smile arc which is not esthetically pleasing [37]. Space availability and stability of dentition are the factors of particular significance especially in a tapered arch group as the intercanine width is the shortest comparing the ovoid and square variety. Any arch expansion in the tapered arch group is deleterious for proper alignment of the lower labial segment since this region is constrained by circumoral musculature [5].

The differences in the various types of malocclusions (Angle Class I, II and III) may affect the maxillary arch form and in the distribution of morphological arch dimension. The present study that provides information concerning the differences of clinical maxillary arch forms in Angle Class I, II, and III demonstrates a baseline knowledge by identifying its morphological variations and evaluating gender differences with respect to arch dimension parameters Jordan refutes the null hypothesis./p>

Although many researchers studied the differences in the maxillary arch forms in various types of occlusal patterns, but it was difficult to compare their results with ours due to variations in the variables incorporated and racial differences.

One of the limitation of this study was small sample size and limited participation rate, thus it does not represent Jordanian population as a whole. In addition, the method used gives information about arch form mathematically ignored the perceived personal judgment, thus other methods to determine arch form was not considered. Another disadvantage was that the mandibular arch form was not considered.

Therefore, further research is still needed to overcome the limitations of this study which includes studying a larger sample and including other methods of arch form determination, different age groups and incorporation of mandibular arch form may be needed before the results of this study can be applied on the general population.

Conclusion

Within the limitations of this study and due to the lack of studies aimed at maxillary arch form variances in Jordan, the following conclusions can be withdrawn:

   The commonest class was class I (54.8%), followed by class II (37.9%) and class III (7.3%). Significantly, more females had Class I (p<0.01) and Class II (p<0.05) occlusal relationship compared with males.

        The mean values of all width and depth measurements increased with age and were significantly (p<0.05) higher in males than in females.

Significantly, class III arches are narrower than class I (p<0.01) and class II arches are the widest (p<0.05).

The most frequently seen arch form was the tapered (52.4%) and ovoid (41.1%)., the least frequent one was the quare one which is recorded in only 6.5%.

The commonest arch form in class I was the ovoid followed by tapered, however, in class II and class III subjects, the commonest arches were tapered.

With this study, it is foreseen that the arch form should be determined in relation with each patients’ pre-treatment maxillary dental model in order to achieve the best esthetic, functional and stable arch form out-come.

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[bluejay--way]

(via https://www.youtube.com/watch?v=NQ1qDnmyEtY)

This video presentation from demonstrates how to analyze and close diastema present in the maxillary teeth with resin composite. Use of instruments, materials and polishing method is demonstrated in detail.